Richards 137NP Instruction Manual

Network Protector Instruction

Manual

Type 137NP

800 to 3500 Amperes

ichards

MANUFACTURING COMPANY, SALES, INC.
517 LYONS AVENUE, IRVINGTON, NJ 07111
Phone [phone] Fax [phone]

IM 1224-001B

DISCLAIMER OF WARRANTIES AND LIMITATION OF LIABILITY

All equipment or component parts manufactured or distributed by Richards Mfg. Co.,
Sales Inc. are expressly warranted by Richards to be free from defect in workmanship or material
when subjected to normal and proper use. Said warrant y shall be for a period of one (1) year
from the date of installation of such equipment no t to ex ceed ei ghteen (18) m onths from the dat e
of shipment of such equipment. Notice of any claim arising out of this warranty shall be made in
writing within the warranty period. Richards’ sole liability and buyer’s sole remedy under this
warranty shall be limited to the repair or replacement, FOB factory, of any equipment or part
determined to be defective in either material or workmanship. This warranty does not appl y to
any equipment, part or component requiring repair or replacement due to improper use or when
determined to have been subjected to abnormal operating conditions or in the event of buyer’s
failure to follow normal maintenance procedures.

No warranty or guarantee expressed or im plied, including any warranty or representation as to
the design, operation, merchantability or fitness for any purpose is made other than those
expressly set forth above which are made in lieu of any and all warranties or guarantees.
Richards Mfg. Co. shall not be liable for any loss or damage, directly or indirectly, arising out of
the use of equipment or parts (including software) or for any consequential damages, including
but not limited to, any claims for buyer’s lost profits or for any claim or demand against the
buyer by a third party.

Richards Mfg. Co. assumes no responsibility for any damage or loss resulting from the use of
this manual. Information in this document is subject to change without notice.

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SAFETY INFORMATION

This manual is intended for use by qualified individuals responsible for the installation,
maintenance and operation of network protectors. Potentially unsafe conditions exist when
installing, maintaining or operating network protectors.

All applicable safety procedures should be adher ed to when installing, maintaining, or operating
network protectors.

Only qualified electrical personnel should be permitted to work on 137NP Network Protectors.

De-energized and rack out the network protector mechanism before any maintenance procedure.

Never defeat safety interlocks on the network protector.

Never energize a partially assembled network protector.

Use extreme caution when installing or working on an energized protector.

Use insulated tools and gloves when working on energized network protectors.

Perform all appropriate electrical tests before any installation or operation of the network
protectors.

WARNING

Before unpacking, installing, servicing, or operating 137NP network protectors read this manual
thoroughly.

For additional information, contact Richards Mfg. Co. directly.

For application information, consult Richards Mfg. Co. or see appropriate ANSI Standards.

Do not operate 137NP network protectors under load except in appropriate enclosures.

The Richards 137NP Network Protectors are designed for secondary network application at
125/216 volt and 277/480 volt wye connected systems. Do not exceed design ratings.

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Submersible Transformer Mounted

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TABLE OF CONTENTS

PAGE

I. OVERVIEW 1

A. Introduction 1
B. 137NP Submersible Network Protector 1
C. 137NP Non-Submersible Network Protector 2

II. INSTALLATION 2

A. Receiving, Handling and Storage 2
B. Transformer Mounted 3
C. Separately Mounted 3
D. Opening Enclosures 4
E. Removing the Breaker Unit 4
F. Connections 7

G. Relay Installation 7

III. MAINTENANCE 8

A. Schedule 8

IV. INSPECTION AND TESTING 10

A. Phasing 11
B. Manual Operation 11
C. Electro-mechanical Relays 11
D. ETI MNPR® Microprocessor Relays 12
E. Electrical Testing 12

F. Checking the Minimum Tripping Voltage 13

G. Checking the Minimum Motor Closing Voltage 13

H. Checking the Motor Control Device 14

I. Mechanical Checks 14

J. Return to Service 14

V. THE REMOVABLE UNIT 15

A. Arc Quenchers 15

B. Contact Construction 800 through 1875 Ampere Protectors 18

C. Contact Construction 2000 through 3500 Ampere Protectors 19

D. Assembly of 2000 through 3500 Ampere Contact Head 20
E. Current Transformers 22
F. Auxiliary Switch 22
G. Mechanical Indicator 24

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H. Operating Mechanism 24
I. Motor Control Device 26
J. Trip Mechanism 27

K. Operating Motor 31

L. Torque Brake 32

M. Gear Assembly 33

N. Manual Operation 33

O. Manual Cutoff Switch 34

P. Closing Linkage 34

VI. THE ENCLOSURE 34

A. Cover Gasket Replacement 35

B. Changing Location of Operating Handle 36

C. Packing 37

VII. DIAGRAMS

Wiring Diagram, 125/216 Volt, 800-1875 Amp Protectors 38

Schematic Diagram, 125/216 Volt, 800-1875 Amp Protectors 39

Wiring Diagram, 277/480 Volt, 800-1875 Amp Protectors 40

Wiring Diagram, 277/480 Volt, 800-1875 Amp Protectors 41

Wiring Diagram, 125/216 Volt, 2000-3500 Amp Protectors 42

Schematic Diagram, 125/216 Volt, 2000-3500 Amp Protectors 43

Wiring Diagram, 277/480 Volt, 2000-3500 Amp Protectors 44

Schematic Diagram, 277/480 Volt, 2000-3500 Amp Protectors 45

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I. OVERVIEW

A. Introduction

The automatic network protectors covered by this instruction book are of the heavy duty,

motor-operated types for application in second ar y AC netwo rk s ystems an d are designated as

submersible and non-submersible.

The Richards 137NP Network Protector consists of a circuit breaker, a motor operated

mechanism, and an ETI Microprocessor Network Protector Relay that combines the

functions of a network master relay, and a network-phasing relay. The ETI MNPR®

provides all modes of operation, including sensitive, insensitive, time delay, instant, watt-var,

and inverse watt-var.

B. 137NP Submersible Network Protector

The 137NP network protectors consist essentially of a circuit breaker, a motor operated

mechanism, the necessary controlling relays, and auxiliary apparatus. These are all enclosed

in a water-tight case, for use in locations subject to submersion.

The breaker unit is an integral unit which is removable from the enclosure. The breaker

forms the rear portion of the unit with the operating mechanism and relay equipment in front.

The cover of the enclosure may be hinged from either side. Clear glass inspection windows

permit reading the operation counter and inspection of the fuses without opening the cover.

The enclosure is provided with an external handl e for manual operation of the breaker unit.

This handle may be mounted on either side of the case as desired. A pressure test valve is

provided so that the enclosure may be tested for air tightness. Convenient pipe plugs are also

located on the side of the enclosure to permit installation of external auxiliary circuits, if so

desired. Lifting eyes are provided on all enclosures. Temporary and permanent mounting

supports are additional provisions. The cover is sealed to the cas e with gaskets compressed

by clamping strips and bolts.

There are two general styles of 137NP network protectors; one with the protector arranged

for wall or framework mounting independently of the network transformer, “Separately

Mounted”, and the other for bolting on to a three phase network transformer, “Transformer

Mounted”. Separately mounted protectors are arranged for connection of t he cables from the

network transformers at the bottom of the enclosure and those to the network at the top. In

the transformer mounted style the connection to the transformer is made by bolting the

protector buses directly to the transformer secondary terminals.

Standard terminal facilities consist of various configurations of tangs, studs and quick

disconnect terminals surrounded by an insulator. Limiter and non-limiter terminals are also

available.

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C. 137NP Non-Submersible Network Protectors

The non-submersible 137NP network protectors are generally similar to the submersible

except that non-submersible enclosures are provided. These protector units are for

applications in clear dry vaults. Equipment mounted enclosures (open framework) prot ectors

are also available.

As in the case of submersible protectors the non- submersible type may be arranged for wall

or framework mounting, or for bolting directly to the network transformers. Terminal

facilities may be arranged for connection of one to four cables per phase, or for bus bar

connections.

All protectors are arranged to permit the ready removal of the breaker unit without disturbing

the cable connections.

II. INSTALLATION

CAUTION: ALL NETWORK PROTECTORS MUST BE MOUNTED VERTICALLY.

It may be well for original users of this device to set one up temporarily in a service shop, so as
to become familiar with its characteristics and construction before installation on the system.
See section on Opening Enclosures.

A. Receiving, Handling and Storage

Care should be exercised when unpacking a protector so that no damage is caused in any

way, and a careful inspection made to see that no parts are damaged, missing or destroyed

with the packing material. Mounting hardware (transformer mounted protectors) is shipped

in separate cartons. Relays are shipped in separate cartons.

In handling or storing network protectors, always keep top up as marked on packaging.

Unsupported network protectors are unstable. Before removing shipping packaging, it is

recommended that a protector be supported from a sling or other suitable means to keep it

from falling over when the crating is removed.

Lift and handle the uncrated protector by the lifting eyes at the top of the case.

NOTE: Do not use the lifting eyes provided on the breaker unit for handling the complete

equipment mounted protector. These lifting eyes are provided for handling the breaker unit

only. Slings with spreaders are recom mended to prevent damage to th e upper terminals and

barriers of the protectors.

Transformer-mounted, top-connected, submersible and non-submersible protectors are

provided with permanent feet so that these protectors will rest upright on the floor.

Separately mounted submersible protectors are provided with temporary feet to protect the

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lower terminals when these protectors are set upright on the floor. These feet may be

removed, when these protectors are bolted in position, to provide cle arance for makin g cable

connections.

Equipment-mounted protectors will not stand unsupported on the floo r. When handling or

resting these protectors on the floor, be car eful not to damage the lowe r barriers or terminals

and, if necessary, place a block under the channel framework

If the protectors are not to be used for some time, store in the packaging in which received.

B. Transformer Mounted Protectors

Submersible and Non-Submersible Units

Remove the breaker unit before mounting the enclosure of transformer mounted protectors

on the transformer. Then remove the throat plate from the rear of the enclosure. The t hroat

gasket is supplied with the network transformer. Mounting hardware is shipped in a separate

bag including the lower supporting feet and the necessary hardware for securing the protector

to the transformer.

The transformer throat gasket supplied with the network transformer should be treated with

Glyptal and assembled to the clean surface of transformer throat flange. This gasket will be

held in position by the dowel pins on this flange.

Lift the protector enclosure and guide it into position using the dowel pins provided on the

transformer throat flange. Then tighten all t hroat bol ts down evenl y so that the throat gasket

is compressed from about 40 percent to 50 percent of its thickness. Add the feet at the

bottom of the enclosure using the proper number of spacers between the bottom of these feet

and the transformer.

Just before placing the unit into the prot ector, clean the transformer terminals with the back

of the bus bar of the protector. Use a brass wire brush and then wipe with a clean cloth.

C. Separately Mounted Protectors

Separately mounted network protectors may be mounted on a suitable framework or against

the wall. The submersible protectors are secured in place by the two lugs at the bot tom back

of the enclosure. The non-submersible protectors are secu red in place b y mounting either in

a pipe framework or placing bolts through the holes provided in the back of the channel

framework

After submersible, separately mounted, protector enclosures are permanently mounted the

feet at the bottom of the case may be removed for better access to the term inals.

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D. Opening Enclosures

Before opening the enclosure, submersible and non-submersible protectors should be

mounted in their final locations or if to be temporarily supported they must be securely

anchored by the lifting eyes to a firm post or part of a building to keep the protector from

tipping forward. To make inspection easier, the protector may be set up on some blocks, but

if this is done, make sure the bottom of the protector cannot move when the breaker unit is

rolled forward.

Most equipment mounted protectors may be rested upright on the floor without removing the

lower barriers or lower terminals. However, when the lower barriers or terminals extend

below the bottom of the channel frame the protector will have to be rested on blocks placed

under the channels. Firmly secure these protect ors to a post or a part of the building so that

they will remain upright.

If the relays are to be tested on a temporarily mounted protector, the protector must be in a

vertical position.

After temporarily supporting or permanently mounting the protector, the enclosure ma y be

opened by unscrewing the cover bolts. If necessary, pry the cover open but do not dam age

the gasket with the instrument used to pry the cover loose.

E. Removing the Breaker Unit (see Figure 1 and 2)

Submersible and Non-Submersible Protectors

Remove the fuses and disconnects as outlined below for the different arrangements of

protectors. Then lift the folding rails up and forward and lower them to the horizontal

position so that they form a continuous surface with the rail in the enclosure. The unit may

be rolled forward, after removing the four mounting screws.

WARNING: The manual operating handle must always be in the OPEN position

before the breaker unit can be rolled forward or back into position for remounting in

the enclosure.

1. Transformer Mounted Protectors

Top connected protectors. Warning, the following sequence must be followed. First
remove the fuses without disturbing the fuse connecting blocks, then remove the fuse
connecting blocks and the screws securing the protector unit to the low voltage
transformer bushing. Reverse above procedure for replacing the protector unit.

2. Separately Mounted Protectors

Remove the fuses at the top of the protector and the disconnecting links at the bottom of
the protector.

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3. Equipment Mounted Protectors

The breaker units for the various arrangements of equipment mounted protectors may be
removed in a manner similar to which the breaker units are removed from submersible
and non-submersible protectors.

Figure 1 - Removable Unit Rolled Out On Rails

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Figure 2 – Removable Unit Supported From Lifting Eyes

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F. Connections

Cable connections should not be made until after fuses have been removed from protector.

Do not replace fuses until all tests and checks outlined under INSPECTION AND

TESTING have been made.

G. Relay Installation

After the protector has been installed either permanently or temporarily for testing, the

network protector relay may be installed in the protector.

To install the relay, unscrew the knurled thumbscrew, move the claw-shaped cam

counterclockwise and then place the relay in position, making sure that the contact blades on

the relay line up with the stationary contacts. Move the cam clockwise to jack the relay into

position. Screw knurled thumbscrews down to secure the relay. The relay is now free to

swing through a large angle. To fasten the relay in its operating position, move the relay

clockwise and pull latch forward.

New network protectors are wired for microprocessor type relays unless otherwise specified.

1. Closing In On Dead Networks

a. Electromechanical Relay

Network protectors with electromechanical relays may not close on a dead network to
which there is no connected load. To be sure protectors will always pick up a dead
network, particularly on a new system, or on spot networks for power only, it is
recommended that a resistor load of 500 watts be connected between phase to which
the phasing relay is connected and ground. Or on delta-connected systems, connected
250 watts between each phase (750 watts total). A 5.0uf capacitor may be used in
place of the 500 watt resistor and 2.0uf capacitor in place of the 250 watt resistors.
When the load on the secondary network grid reaches a point where all of the load
will never be disconnected, the above mentioned resistors or capacitors may be
removed from the grid.

b. ETI MNPR® Microprocessor Relay

Network protectors with ETI MNPR® microprocessor relays will close on a dead
network with or without connected load.

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III. MAINTENANCE

A regular inspection and maintenance schedule for network protectors is recommended. While
experience will best indicate the frequency with which inspections should be made, the following
routine is suggested.

In all cases open the protector manually and lock in the open position first, then remove fuses
and the test caps before working on or inspecting or testing protector.

A. Schedule

1. At Installation
Complete inspection and test. See INSPECTION AND TESTING.

2. After First 24 Hours of Automatic operation

Read operation counter to make sure that the protector is not operating excessively.
Twenty-five operations or less are not excessive for initial installations, and even fifty
operations are not too many if the network load is to be inc reased soon. Additional load
will eliminate a large percentage of the operations. If the number of operations during
the first 24 hours is considered excessive, a check should be made to see that the
mechanism operates positively. If it does, the protector is being operated by numerous
power reversals. To correct this, the programming of the relay may need to be revised.

3. After First 48 Hours

Again read operation counter. If the number of operations is normal, daily readin g may
be discontinued.

4. After First Week

Read operation counter.

5. After First Month

Read operation counter.

6. After First Six Months

Complete inspection and test.

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7. Yearly

Fully inspect and test protectors including relays and perform the following preventive
maintenance.

a. Remove breaker from the enclosure and inspect and clean the contacts.
b. Check wiring terminals for tightness.
c. Remove trip mechanism and inspect and clean mechanism if necessary. The

protector mechanism is thoroughly lubricated at the factory and this lubrication
should last for some time. However, if it appears that the mechanism requires
lubrication, use SAE-30 machine oil on bearings. Wipe off all excess as the
excess will collect dirt and nullify the effect of the lubricant.

d. The bearings of the secondary latch shaft, Figure 15, should have just a drop of

SAE-30 machine oil added if necessary and the latch surface should be coated
very thinly with high grade petroleum jelly, to prevent rust.

e. Check the level of the lubricant in the gearbox, Figure 17. If necessary add

sufficient #4 hydraulic oil

f. Remove one brush holder and brush from motor and inspect commutator surface

with flashlight. If necessary, remove and disassemble motor and clean
commutator.

g. Lubrication of the motor bearings should not be necessary during the life of the

motor. However, if lubrication is found necessary after a number of years,
remove the motor, dismantle it, wash the bearings out thoroughly and repack them

with a small quantity of grease.
h. Clean torque brake when motor is removed.
i. Check auxiliary switch contacts and clean if necessary.
j. Check motor control device contacts and clean if necessary.
k. Check mechanical indicator.

8. After Heavy Primary Short Circuits

Inspect protectors which have interrupted short circuits, cleaning the devices and
resurfacing the breaker contacts.

9. De-en e rgize Primary Feeders

Each feeder should clear completely, as indicated by the feeder voltmeter, if all the
protectors are set to trip on transformer exciting current. On re-energizing the feeder,
each protector should reclose as the load increases.

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IV. INSPECTION AND TESTING

CAUTION: DO NOT OPERATE THE PROTECTOR, EITHER MANUALLY OR
ELECTRICALLY, UNLESS IT IS IN A VERTICAL POSITION.

Before placing the protector in service it should be tested. Tests may be made with protector in
its final location or with the protector in a temporary location in the service shop. If temporarily
located be sure to secure the protector as des cribed under Receiving, Handling and Storage.
The breaker unit of submersible protectors may be either bolted in place in the housing or rolled
out of the rails.

Always open the protector manually first; second, open the enclosure cover; third, remove fuses,
and fourth remove all test caps before testing, working on, or inspecting the protector.

Test caps, Figure 3, located on the auxiliary panel below the breaker mechanism, provide a
means of disconnecting control wiring from the main circuit . This is accomplished b y removing
insulated test caps to de-energize control wiring and tightening these test caps to energize control
wiring. With the insulted test caps removed, provision is made on the projecting studs for the
attachment of test clips so that control wiring may be energized from a separate source.

On new installations the fuses should be removed before the cables ar e con nected and should not
be replaced until the following tests are completed.

The protectors are shipped with the manual operating handle wired in the open position, the trip
latch tied up and the folding rails wired down. Remove these ties before starting tests.

Figure 3 – Auxiliary Panel, Potential and Test Switches

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A. Phasing

Phase out connections to protector to insure that “cross-phase” connection will not be made
when the breaker is closed. Network voltage is available on network side of fuse mounting.
Transformer voltage is available on opposite end of fuse mounting when the protector is
closed.

B. Manual Operation

Close and open the breaker several times by hand. To do this swing the manual operating
handle from the “open” to the “closed” position and when the breaker is c losed return to the
“open” position. The breaker should close with considerable pressure. If the hand -wheel of
the motor is turned the motor cam ma y be advanced to a position where it will prevent the
normal resetting of the mechanism after tripping. If this happens, turn the hand-wheel
clockwise until the mechanism resets. Then turn two more revolutions. Now close the
breaker manually and trip by lifting the extended lever above the trip coil. Repeat this
operation, returning the manual handle to the “automatic” position. The trip mechanism and
operating mechanism should reset.

C. Electro-mechanical Relays

The correct operation of the electromechanical type network master relay depends upon the
application to the relay coils of currents and voltages of the proper phase s equence. For this
reason the phase sequence of the network should be ch ecked before putting a protector into
service. This can be done by making a temporary reconnection of the phasing relay and
observing its operation as follows:

1. Make the temporary change in the wiring of the phasing relay as indicated on the
wiring diagram for the network protector.

2. Replace test caps B, C, and F only.

3. Trip protector open and move operating handle to “open” position. Do not close
protector during this test.

4. Connect the network side of the protector to the network.

5. Observe the op eration of the phasing rela y contacts. If the relay contacts close with a
strong torque toward the right, the phase sequence is 1, 2, 3. If the relay contacts
open or move to the left, the phase sequence is 3, 2, 1.

The phase sequence of the protector is determined by the lead connections as shown on
the wiring diagram. In general, network protectors are wired for 1, 2, 3 phase sequence at
the factory. Protectors may be obtained which are wired 3, 2, 1 phase sequence if
desired. (Note: Protectors wired for 1, 2, 3 phase sequen ce may be used with a 3, 2, 1

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phase sequence provided four leads are interchanged in accordance with the wiring
diagram).

6. Return the phasing relay connections to normal.

7. Remove test caps B, C, and F for the following tests.

D. ETI MNPR® Microprocessor Network Protector Relays

The relay will not close its contacts on a crossed phase system. It is, also, insensitive to
phase sequence and will function accurately for protectors wired with phase sequence 1-2-3
and installed on systems wired 3-2-1.

E. Electrical Testing

When these observations have been completed the protector may be operated electrically to
check the mechanism operation. These tests should be performed usin g a network protector
test kit. Explicit instructions are included with these test kits. If a test kit is not available the
following method can be used.

1. Remove the electromechanical or solid state relay and insert a jumper across
terminals 1 and 2 (wire No. 6-6A) of the phasing relay plug (if provided).

a. On 120/216V units connect a 216V source to studs K and L to energize the

operating circuits. Connect the closing contact of a control switch to terminals 2
and 3 (wire No. 6-11) of the master relay plus and a tripping contact to terminals
1 and 3 (wire No. 41-11). Activate the “closin g contact” of the control switch. If
the manual operating handle of the protector is in the automatic position the
protector will close.

Activate the “tripping contact” of the control switch. The protector should now
trip.

Turn the manual handle to the “open” position. Activation of the closed contact
of the control switch should not close the protector.

b. On 277/480V units connect a 480V source to studs 11 and 21 for trip circuit test,

and studs 11 and 3A for motor and motor control circuit tests. Repeat test a.
above.

If the mechanism over travels, and goes through a trip-fr ee operation befo re closing, remove
the motor and clean torque brake. If the breaker has been turned upside down or front side
down, oil from the gearbox may run into the torque brake making it ineffective.

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Figure 4 shows a test set up for obtaining the various voltages required for testing the
protector mechanism. The variable auto-transformer should have inputs of 208 and 460 volts
with a 16 amp current rating.

Figure 4 – Single Phase Test Circuit

F. Checking the Minimum Tripping Voltage

Using the auto-transformer test set up as described in Figure 4 apply 16 volts to studs K and
L on 125/216V units and 36 volts to studs 11 and 21 on 277/480V units. Connect the
tripping contact of a control switch across terminals 1 and 3 (wire No. 41-11) of the master
relay plug. Activation of this contact should trip the protector.

G. Checking the Minimum Motor Closing Voltage

Using the auto-transformer test set up as described in Figure 4, appl y 157 volts to studs K
and L on 125/216V units and 200 volts to studs 11 and 3A on 277/480V units. Connect the
closing contact of a control switch to terminals 2 and 3 (wire No. 6-11) of the master rela y
plug. Close the motor relay by hand by lifting up the plunger. Activate the closing contact
of the control switch. The motor should close the protector. There is no adjustment for
minimum closing voltage. This test merely shows that the motor has sufficient torque to
close the protector.

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H. Checking the Motor Control Device

Using the test set ups as previously described apply the following voltage levels to the
protector control circuits.

1. For 125/216V units. The motor control device should never pick up at 166 volts and
should always pick up at 180 volts. With the protector open apply 166 volts to studs
K and L. Activate the closing contact of the contr ol switch. Th e prot ector should not
close. Repeat 10 times. If pickup occurs reset the motor control device by turning
the calibrating nut (see Figure 13) up. Recheck.

Trip protector and apply 180 volts to studs K and L. Activation of the control switch
closing contact should now close the protector. Repeat 10 times. If it does not, turn
the calibrating nut of the motor control device down and recheck at 180 and 166
volts.

2. For 277/480V units the motor control device should never pick up at 212 volts and
should always pick up at 230 volts. Apply these values to studs 11 and 3A and repeat
test 1.

Where laboratory test facilities are not available or for other reasons it may be desirable to
test the network relays in the field on the protector. These tests should be performed using a
network protector test kit. Explicit instructions are included with these test kits.

I. Mechanical Checks

1. Check for resetting on trip-free operation. See instructions under Trip Mechanism.

2. Check the level of the oil in the gearbox. It should be up to the bottom of the ¼ inch

plug on the side of the gearbox. If not, apply a sufficient amount of #4 h ydraulic oil to
bring the level to the proper point.

3. See that the polished part of the secondary latch shaft, Figure 15, is covered with a

very thin coat of high grade petroleum jelly.

J. Return to Service

1. Replace all test caps.

2. Replace relays.

3. Replace fuses.

4. Close cover.

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5. Move manual operating handle to automatic position. If voltage conditions are

proper, the breaker will close.

6. Place air pressure test on enclosure to be sure it is tight. Se e instructions u nder THE

ENCLOSURE.

During the mechanism tests, note the operation of the mechanical indicator and the operation
counter. The indicator should read closed when the breaker is closed and open when the
breaker is open. The operation counter should record each complete protector operation.
Before energizing the cont rol wiring make sure that the contacts of the m otor control device
are latched open.

It should be unnecessary to make high potential tests on protectors, because they are
completely tested before leaving the factory. If, however, it is desired to make such tests a
potential of 2000 volts AC may be applied for 60 seconds from each main conductor to
ground and between any two main conductors.

Caution: During such tests see that the motor leads are disconnected and network
relays, as well as the indicating lamps (if provided) are removed from the protec tor.

The motor may be tested at 900 volts AC 60 cycles, for 60 seconds, and the relays tested
separately at 1500 volts AC for one second. Field hipot test values are 75 percent of factory
test values.

V. THE REMOVABLE UNIT

Figure 5 shows a typical removable unit for the 137NP network protectors. The circuit br eaker
part of this unit is of the air-break type and it utilizes arc quenchers for restricting and
extinguishing the arc.

The details and arrangement of the main conduc tors vary in accordance with the amper e ratings
of the protectors, as well as with the different types of protector mountings. For th e 800 through
1875 ampere ratings these main conductors or contact bars ar e made of solid copper, while for
the 2000 through 3500 ampere ratings they are made of square hollow copper tubing

A. Arc Quenchers (see Figure 5 and 6)

The arc quenchers are held in place by two captive screws at the sides of the assembly.
Loosening these two supporting screws permits tilting the arc quencher forward for
examination of the arcing contacts of t he breaker. For com plete removal o f the arc quencher
it is also necessary to remove the four screws in the front of the assembly which secure the
end of the flexible connection to the terminal plate of the magnetic blowout coil. On
replacing the arc quencher, make sure that this flex ible connection is properly connected an d
all screws are tight.

15

Figure 5 – Removable Unit On Network Protector Stand

16

Figure 6 – Contact 800 to 1875 Amp Units

Figure 7 – Contact 2000 to 3500 Amp Units

17

B. Contact Construction for 800 through 1875 Ampere Protectors

Each breaker pole has a set of main current-carrying contacts and a set of arcing contacts (see
Figure 6). The main current-carr ying contacts consist of pieces of silver-a lloy brazed to the
contact bars and to a bridging block. The silver-alloy pieces on the contact bars are
machined flat and the silver-alloy pieces on the ends of the bridging block are rounded
slightly to obtain line contact. The main cu rrent-carrying contacts open first and the current
is transferred to the arcing contacts which open last. In closing, the arcing contacts make
first and the main current-carrying contacts last.

With the breaker open, the arcing contacts should be separated by a gap of one inch
minimum. With the arcing contacts on one pole just touching, the maximum gap on the other
two poles should not exceed 1/32 inch. With the arcing contacts just touching, the gap at the
main current-carrying contacts should be 3/16 inch minimum and 3/8 inch maximum on the
top, and 1/8 inch minimum and 5/16 inch maximum on the bottom. During the closing
operation the crossbar and contact support should continue to move a minimum of 3/32 inch
toward the closed position after the main contacts touch. This compresses the heavy springs
behind the main bridging contact blocks to give the required contact pressure.

The contact surfaces should always be kept clean and smooth. After heavy short circuits they
should be carefully inspected and, if necessary, any rough or high spots should be removed.
Use a fine, clean file and wipe with a clean, dry cloth. When filing contacts remove the high
spots only, do not file to the bottom of deep pits. Care should be taken to maintain a line
contact as much as possible. To check the amount of contact obtained, take contact
impressions by holding, between the contacts, a piece of t hin carbon paper with tissue paper
on the carbon side and closing the breaker. Open the breaker and examine the impressions
on the paper. Good contact is indicated if a well defined impression shows for 75 per cent or
more of the length of the contact. Good contact i s also indicated if a 0.001 inch feeler gage
cannot be inserted between the main silver contacts for more than 25 percent of the length of
the contact.

The movable arcing contacts are held in place b y high-strength hexagon-head screws which
are locked in position with lockin g plates (see Figure 6 and 7). When replacing the arcing
contacts make sure that all screws are tight and that the lockin g plates are bent back around
the screw heads.

The main current-carrying contacts have adequ ate capacity to carry full-load current ev en if
the full line contact has been somewhat reduced, and replacement under normal
circumstances is unnecessary. However, if it sho uld be necess ary to remo ve a main bridgin g
contact, the following procedure is suggested (see Figure 6):

1. Remove the barriers and arc quenchers.

2. Close the breaker

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3. Block the breaker in the closed position to prevent accidental tripping. This can be
done by wedging a block of wood between the cross head and the trip mechanism
frame.

4. Remove the two stop screws with lock washers on the sides of the contact bridging
member.

5. Remove the blocking and trip the protector open.

6. The contact bridging member can now be lifted out.

7. To replace the contact, reverse the above procedure.

C. Contact Construction for the 2000 through 3500 Ampere Protectors

Each breaker pole has a movable-contact unit assembly consisting of several individually
sprung bridging members in parallel. The bottom ends of these bridging members pivot
around a bearing block welded to the lower main contact bar. Contact surfaces should be
lubricated at the joint where they pivot on the bearing block welded to the lower main contact
bar. The parts are silver plated and sepa rate springs hold the bridgin g members in fixed-line
contact with the bearing block. Contact buttons brazed to the top of the bridging members
make point contact with other contacts brazed to the upper main contact b ar. All these top
contacts are low-resistance silv er alloy and each brid ge carries its share of the total current.
Each pole-unit assembly is arranged such that one silver-alloy contact (the arcing contact)
makes first and breaks last, and two silver-alloy contacts (intermediate contacts) make and
break second. The remainder of the bridging members have silver-alloy contacts (main
contacts) and these contacts make last and break first. There are four silv er-allow contacts i n
the 2000 through 3500 ampere assembly.

With the breaker open, the arcing contacts should be separated by a gap of 1-1/16 inches
minimum. With the arcing contacts on one pole just touching, the maximum gap on the other
two poles should not exceed 1/32 inch. With the arcing contacts just touching, the gap at the
intermediate contacts should be 7/32 inch minimum and 9/32 inch maximum. With the
intermediate contacts just touching, the gap at the main contacts should be 3/32 inch
minimum and 5/32 inch maximum. During a closing operation the crossbar and contact
support should continue to move a minimum of 3/32 inch toward the closed position after the
main contacts touch. This compresses the contact springs to give the required contact
pressure.

The surface of the contact buttons should be kept clean and smooth. Any pronounced rough
or high spots resulting from a heavy short circuit should be removed by filing with a fine,
clean file. After filing, wipe with a clean, dry cloth. When filing contacts, remove the high
spots only, do not file to the bottom of deep pits.

The movable arcing contacts are held in place b y high-strength hexagon-head screws which
are locked in position with l ocking plates, (see Figure 6 and 7). When replacing the arcin g

19

contacts make sure that all screws are tight and that the lockin g plates are bent back around
the screw heads.

Replacement of the bridging contact members under normal circumstances should be
unnecessary. However, if required, the following procedure is suggested (see Figure 7):

1. Remove the barriers and arc quenchers.

2. Close the breaker.

3. Block the breaker in the closed position to prevent accidental tripping. This can be
done by wedging a block of wood between the cross head and the trip mechanism
frame.

4. Remove the cam locking screws.

5. Remove the blocking and trip the protector open.

6. Remove the cotter pins and push out pivot pin “A”.

7. Disconnect the small flexible connection at the bottom end of the arcing-contact
bridging member.

8. Loosen pivot screws “B” and the entire contact assembly can be lifted out as a unit.

9. To replace the contact assembly, reverse th e above procedure

D. Assembly of 2000 through 3500 Ampere Contact Head

Refer to Figure 8

1. Stack contacts and insulation with a 3/8 inch diameter pin in the location of Pin “A”.
This temporary pin should have a length less than the inside dimension of the contact
carriage.

2. Assemble into carriage with Pin “B” and “C” using a 0.5 inch diameter rod in Pin
“D” location.

3. Place assembly in a vise to clamp he surfaces indicated by “X”.

4. Compress springs until Pin “A” can be used to push out the temporary 3/8 inch
diameter pin.

5. Removal of Pin “D” makes unit ready for assembl y into protector unit. Be sure and
lubricate contact surfaces at the point where they pivot on bearing block welded to the
lower main contact bar.

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Figure 8 – Contact Head

Refer to Figure 9

1. The contact head is assembled to the cross bar with Pin “E” and to the stationary
copper, hinge contact with pivot 6144209.

2. Add locking plate.

3. Force lockin g plate agains t Pin “B” with some suitabl e lever in contact wi th Pin “A”
to establish spring pressure for the hinge contact.

4. Line up hole for 5/16 inch – 18 hexagonal screw with screw driver in slot used for Pin
“E”.

5. A 5/16 inch – 18 hexagonal screw and locking plate are required on each side.

Figure 9 – Contact Head

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E. Current Transformers

One current transformer, for us e with the network relay, surrounds and is mounted on each
pole of the breaker unit. Each current transformer has two windin gs; the phasing winding
which is energized when the breaker contacts are open by the voltage across the breaker
contacts and a secondary winding which is connected to the network relay current coils.

Current transformers are mounted directly on the main bus copper and may be removed by
moving the protector unit forward, disconnecting the wiring at the current transformer coil
terminals and removing the screws fastening the mounting brackets to the buses. When
replacing current transformers, care should be ex ercised to insure that they are plac ed on the
bus with the polarity mark H1 facing the network distribution transformer terminals. Also be
sure that all connections are in exact accordan ce with original connections as designated on
the wiring diagram for the particular protector involved.

F. Auxiliary Switch

Immediately below and to the right of the main breaker crosshead is mounted a unit assembly
of auxiliary switches, which are operated by a rack and gear connected to the crosshead.
These switches open and close the necessary control circuits as a function of breaker contact
position.

After approximately every 5000 operations of the protector, the auxiliary switch contacts
should be examined, and, if found to be pitted, they should be dressed with a fine file. It is
not necessary to remove contacts to dress them, however, if necessa ry the movable contacts
of this switch can easily be removed. Remove the stud above the wire connection. With the
contact open, push it towards the stationary contact and lift up. The contact will lift out and
can be repaired or replaced. This operation can be done with the auxiliary switch in position
on the breaker unit.

The complete auxiliary switch assembly may be removed by disconnecting the driving link,
and the control leads, and removing the two screws holding the mounting bracket to the
breaker frame. The disassembly of the auxiliary switches is not recommended due to the
many operating cams arranged in positions easily disturbed when dismantled.

After an auxiliary switch has been installed on the breaker unit, connect the rack and gear to
crosshead, (see Figure 11). Manually operate breaker to insure proper operation before
wiring. Removing screw “A” and slide will permit guide to drop down, so that rack can be
raised to provide a close adjustment on gear for the following sequence of operation.
Operate breaker manually. Contacts 1, 2, 3, and 9 should close when the arcing tips have
between 3/16 inch and 1/16 inch gap. If contacts 1, 3 and 9 should operate oppositely, then
rotate the gear approximately 180 de grees, so that these contacts will be positivel y closed at
the same time in the above mentioned sequence. If the proper sequence cannot be obtained,
the internal cams have been incorrectly assembled and the auxiliary switch must be removed
and the cams relocated. After the auxiliary switch contacts have been properly adjusted, the

22

wired should be connected to their respective locations, circuits checked, and the protector
electrically operated to make sure all circuits are completed by the auxiliary switch.

Figure 10 - Auxiliary Switch

Figure 11 – Rack and Gear Mechanism

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G. Mechanical Indicator

The protector is equipped with a mechani cal indicator to tell whet her the protector is “op en”
or “closed”. This mechanical indicator is operated by a linkage directly connected to the
breaker crosshead. It exposes either the word “OPEN” or the word “CLOS ED”, depending
on the position of the breaker contacts. Provision is made for adjustment o f the length of the
operating link.

H. Operating Mechanism

The mechanism for closing the breaker of the 137NP network prot ectors is of the gear-driven
cam, motor operated type. (see Figure 5). The operating motor is mounted on the worm and
gear housing to the left of the closing linkage. The motor drives the worm through a torque
brake which permits free running of the motor while torque is being transmitted from the
motor to the worm, and serves to stop the motor’s rotation immediately when the motor is
de-energized. The brake assemb ly serves as a coupling between the moto r and worm shaft
and is mounted on the lower end of the motor shaft in the upper part of the gear housing.

Sequence of Operation

The sequence of operation of the 137NP network protectors may be best explained by
consideration of the simplified control diagram by Figure 12.

Assume that the breaker is open. The sequence on closure is as follows:

1. When the proper voltage conditions exist the relay will close its “closing contacts.

2. This action will energize the coil of the motor control device through the “b” and “c”
switches (assuming that the manually operated handle is in the automatic position).

3. The motor device will then close its contacts and energize the operating motor.

4. As the breaker closes, two small cams on the main closing cam shaft will
mechanically open the two contacts independently and the torque brake will stop its
rotation.

If, when the protector closed, a primary feeder fa ult, or other conditions should occur which
would cause sufficient power reversal to operate the network r elay, tripping of the protector
will occur as follows:

1. The network relay will close its tripping contacts, thus completing a circuit through
the trip coil and series “a” switch.

2. The trip coil armature will then pick up (if the impressed voltage is 7-1/2 percent of
normal or over) and release the trip mechanism latch, allowing the breaker to open.

24

3. When this occurs, the “a” switch will open, de-energizing the trip coil, and the “b”
switch will close, restoring the protector to its initial state.

When the breaker is closed or open, an “a” or “b” switch will indicate the breaker position
for customer use. If the manual operating handle is m oved to the “open” position, the “c”
switch will open the closing circuit to prevent closure of the protector.

Figure 12 – Simplified Control Circuit

25

Figure 13 – Motor Control Device

I. Motor Control Device

The motor control device is mounted in the lower left-hand side of the closing mechanism
assembly (see Figure 2). This device (see Figure 13) performs the necessary functions of
energizing the motor when the cl osing contacts on the rela ys close, and of de-energizing the
0motor after the breaker is completely closed. The device consists essentially of two
contacts connected in parallel, an individual latch for latching each contact in the open
position, a coil and plunger for releasing both contact latches when energized, and a lever
arrangement whereby two small cams on the main closing cam shaft will mechanically open
the contacts independently. These two small cam s for opening the contacts are staggered on
the shaft such that either one or the other contact is always free to close. The location of
these cams on the shaft is such that the second contact is not opened until after the breaker is
latched in the closed position. Before either contact is opened during a closing operation the
“b” switch has opened and has de-energized the coil of the control device.

This device should be adjusted to pick up electrically as approximately 80 percent of the
normal motor circuit voltage (see INSPECTION AND TESTING). This must be checked
with an instantaneously applied voltage. To adjust this pickup, secure holding nut and turn
calibrating nut in a clockwise direction to decrease the voltage required to pick up armature.
To increase the pickup voltage, reverse the above procedure. The contacts of this device
must be latched open when in stalling protector in system.

26

No adjustment is required other than that necessary to maintain the pickup value desired.
The contacts, however, should be examined after every 5000 operations; and, if necessary,
dress contacts with a fine file on high spots only, do not file to bottom of pits.

Occasional renewal of contacts m ay be necessary. The stationary contact may be remov ed
and replaced by removing the two screws located on front of cont act. When replacing the
movable contacts, remove screws “a” located on top and screw holding flexible connection to
contact. When installing new contact make sure that all screws are tight and contact is lined
up.

To replace coil, the motor control device must be removed from th e breaker unit and wires
disconnected. Disconnect coil leads from their terminals. Remove screws “b” (s ee Figure

13) and drop armature taking care not to misplace washer located on top of armature.
Remove the tube and pole piece. The coil ma y now be removed from right side of device.
To install, reverse the above procedure.

An adjustment has been provided which permits the position of the motor control device to
be varied, thus controlling the point at which the motor is de-energized (see Figure 13). An
adjusting screw fastened to the mechanism frame will advance the motor cutoff point if
turned counterclockwise. If turned clockwise, the motor cutoff point is ret arded. Before this
adjustment can be changed, the lock screw of the device and the l ock nut on the adjusting
screw must be loosened. This adjustment will control the opening movement of the control
device contacts. The contacts must open far enough to be l atched in the open position, but
must not open so far that they touch the upper member of the control device frame.

J. Trip Mechanism

The trip mechanism in use on 137NP network protectors is sel f-resetting (see Figure 14A, B,
C). Rotation of the latch shaft permits the latch to rotate about its pivot, releasing the latch
roller and allowing the breaker toggle linkage to collapse. Both the breaker mechanism and
the trip mechanism reset through the action of resetting springs. In order for the latch to reset
properly, the breaker mechanism must reset before the trip mechanism. For this reason, the
holding cam on the latch roller link holds the latch out of the reset position as shown in
Figure 14B until the breaker mechanism is fully reset. Resetting of this trip mechanism is
positive and no adjustments are required.

The trip coil should cause the breaker to be tripped open when any voltage from
approximately 7-1/2 to 106 percent is applied to the tripping circuit.

1. Mechanism Adjustment

a. Checking operation for resetting after trip-free operation.

27

It is essential that the breaker mechanism reset properly not only when tripped from
the fully closed position but also after trip-free operation. Resetting of the latches
after trip-free operation should be checked by the following method.

Figures 14A, B, C – Trip Mechanism

28

With the operating handle in the automatic position hold up the hand-trip finger (see
Figure 15) such that the secondary latch is disengaged. Then energize the motor
closing circuit at 230 volts (106 percent) and aft er two or three trip-free operations
release the hand-trip finger. On the next operation the secondary latch should engage
the latch shaft and the motor mechanism should then close the breaker and stop.

Should the above check show that the latch is not resetting properly, the following
possible sources of trouble should be investigated.

i. The motor closing cam may be in such a position that the lower roller on the

bell crank strikes it before resetting. If such is found to be the case, turn the
motor by hand until the cam goes past the roller and the bell crank drops into
the reset position. The motor closing cam could get into such a position to
prevent resetting either by excessive slipping of the motor brake or because of
partial rotation of said cam be turning the motor by hand.

ii. There may be a bind in the main closing mechanism which prevents the bell

crank from dropping into the reset position. This could be caused by dirt or
other foreign material getting into the mechanism, or by incorrect assembly if
for any reason the breaker has been taken apart.

iii. The torsion spring on the main latching toggle may not be turning the main

latch arm back into the reset position. This again could be caused b y binding
or excessive friction resulting from dirt or other foreign material, or by
incorrect assembly if for an y reason the mechanism has been taken apart.

b. Adjustment of Tripping Solenoid

Automatic tripping of the breaker is accomplished by energization of the coi l of the
tripping solenoid which is mounted on the right-hand side of the trip mechanism. The
plunger of this solenoid strikes an arm on the secondary latch shaft, thereby rotating
the shaft and freeing the latch. There should be sufficient over travel of the trip
plunger to insure position tripping at all times. To check this over travel, first loosen
the locking nut (see Figure 15) on the latch adjustment screw and turn the screw
down until it just trips the breaker. Then pick up the trip plunger by hand and
measure the travel of this plunger between the point where it strikes the lat ch arm and
the point where it can be raised no higher. This over travel should be approximately
1/16 to 3/32 inch. If the over travel is less than this the latch arm should be bent
down to obtain the proper over travel. After checking the over travel of th e trip
plunger, the latch adjustment screw must be reset. To do this turn the screw down
until it just trips the breaker and then back it off 1-3/4 minimum to 2 full turns. Lock
the screw in this position with the locking nut.

Protectors have been carefully adjusted in the factory for low voltage tripping limits,
and it should not be necessary to make any readjustments.

29

Figure 15 – Trip Solenoid

Figure 16 – Buffer Assembly

30

c. Replacement of Buffer Washers

The shock of the breaker opening is deadened by two buffer stops, one on either side
of the mechanism assembly. The buffer washer used on these stops are made of a
material which combines the necessary shock-absorbing qualities with long life and
durability, and they should be replaced only by similar washers of the same material
obtained from the factory. These buffer washers are 1/8 inch thick when new. If,
after continued use, the thickness becomes less than 1/16 inch, they should be
replaced with new ones. To replace the buffer washers proceed as follows:

Refer to Figure 16.

Close the protector and tie the latch, or block crosshead so that it cannot be tripped
accidentally. Remove the cotter pins which hold the buffer pins in place and then
remove the buffer pins. Replace the buffer washers with new ones and reassemb le in
the protector. Before putting the cotter pins back, trip the protector and check to see
that the contact supporting frame strikes both buffer pins simultaneously. If not, add
or remove spacer washers under the heads of the buffer pins until it does. The
adjustment is correct when the following conditions exist.

When the breaker open and the contact supporting frame resting on the buffer stops,
the trip resetting plunger should be bearing on the reset cam and holding the
secondary latch in the reset position. When in this position the trip resetting plunger
should be just starting to compress its spring and move relative to the crosshead
frame. In no case should the spring behind the trip-resetting plunger be compressed
solid.

The complete trip mechanism may be removed as a unit by disconnecting the trip coil
leads, and removing the four screws holding the trip mechanism frame to the main
mechanism frame. The trip mechanism may then be lifted and removed completely.

CAUTION: The breaker must be in the “open” position before the trip
mechanism is unbolted from the mechanism.

K. Operating Motor

The operating motor is of the totally enclosed, universal ball-bearing type which requires
minimum maintenance. The motor should be inspected and cleaned periodically to insure
perfect operation. This can best be accomplished b y removing the motor from the protector,
removing small hand wheel from the end of motor shaft by loosening the screws, removing
the brushes located on side of motor fram e and removing the two studs holding the motor
frames together. This will permit complete dismantling of the motor for reconditioning and
inspection.

The motor is rated for intermittent service, and reasonable care should be exercised when
testing network protectors to avoid overheating of the motor by repeated operation.

31

Operating motors may be removed by disconnecting the leads from the terminals provided,
removing the three bolts holding the motor to the gear housing, and lifting the motor
vertically.

Figure 17 – Motor, Torque Brake and Gear Reducer

L. Torque Brake

The torque brake (see Figure 17) applied between the motor and the gear reducer unit serves
as a coupling and controls the over travel of the mot or closing cam when the motor is de­energized. This torque brake assembly consists of three units; (1) brake assembly keyed to
gear reducer, (2) impeller keyed to motor shaft, and (3) brake drum keyed in the gear
housing. When the motor is energized, the impeller releases brake shoe from the brake drum
and transmits torque directly to the gear reducer. When the motor is de-energized, the motor
torque on the impeller is released permitting the brake shoe to engage on brake drum and
stop the mechanism.

The torque brake does not require adjustment other than an occ asional inspection to insure
that no oil or grease is present on the brake shoes or drum surfaces. When replacin g brake be
sure that the brake drum is in position. Before replacing motor make sure that impeller is

32

properly located on brake (see Figure 17) and spacing washers when used between the
impeller and motor, should be replaced. Rotate hand wheel on motor to insure that no
binding is present before operating.

M. Gear Assembly

The worm and gear are enclosed in a housin g to form a unit assembly which is mounted to
the side of the mechanism frame casting by three bolts.

The complete gear assembly, either with the m otor removed or attached, can be rem oved by
removing the three bolts holding the gear casing to the side of the mechanism frame and
sliding the assembly off the end of the manual operating shaft.

N. Manual Operation

Manual operation of the breaker unit of the 137NP protectors is provided through a shaft
concentric with the worm wheel and main cl osing cam shaft. This shaft carries a cam which
is similar to the main closing cam and acts against the closing bell crank in the same manner
to close the breaker, and is arranged to operate a push rod which lifts the primary latch to trip
the breaker open.

Figure 18 – Manual Cut Off Switch

33

O. Manual Cutoff Switch

The manual cutoff switch (see Figure 18), located on the right side of mechanism and
actuated by a cam on manual operating shaft, opens the “closing” cir cuit when the manual
handle is rotated to the “open” or “closed” position, thus preventing the protector from
attempting to reclose with the handle in either of these positions. When the handle is rotated
to the “closed” position, the breaker will be closed but will trip free from the manual handle
if the trip coil is energized or the trip latch is released. When the handle is in the “automatic”
position, the protector will perform its normal automatic functions.

The contacts of this switch should be examined periodically. If necessary, dress contacts
with a fine file in high spots only, do not file to bottom of pits

P. Closing Linkage

The main closing linkage is contained in the main mechanism frame.

The complete operating mechanism can be removed from the breaker by disconnecting the
control leads, and removing the two bolts on each side of the main mechanis m frame, which
hold this frame to the breaker frame. This operation may be performed either with the motor,
gear assembly and trip mechanism in place, or with any of these parts removed.

CAUTION: Breaker must first be open.

VI. THE ENCLOSURE

The 137NP network protector (see page iii) is provided with a submersible enclosure. All cases
are provided with a cover which may be hinged from either side and an external manual
operating handle which should always be mounted on the side opposite the cover hinges so as to
be accessible when the cover is open. If the enclosure is opened before the protector is mounted
in its final location, be sure to secure the top of the enclosure to a solid support to prevent the
protector from tipping forward when the unit is rolled forward.

The cover is provided with a gasket for making a waterti ght joint wi th the case. Gasket and case
surfaces should be cleaned to insure a tight joint. Before closing the cover, it is advisable to
cover the gasket surfaces with a thorough coatin g of flaked graphite or water pump grease for
cork and flaked graphite or talc for Corprene. On quick opening boxes with rubber gaskets use
talc. This procedure should be followed each time the cover is closed. The cover should be
clamped against the case with the clamping arrangement provided by tightening the bolts
gradually to insure an even distribution of pressure on the gasket.

All pipe thread fittings including pipe plugs, inspection window holders and pressure test valves,
if removed, should be replaced by applying Glyptal or white lead to threads to insure a tight
joint. All wiping sleeve cable bushing nuts, before being replaces, should be coated with a
mixture of graphite and oil so that they can be removed or tightened easily.

34

After sealing the enclosure, all submersible protectors should be given an air pressure test. An y
satisfactory air or nitrogen testing equipment may be used. Inflate the case with gas to not more
than six pounds per square inch leave the pressure in the case for 24 hours. The pressure drop
should not be more than two pounds. If it is, investigate for leaks; leaks may be found by
painting the protector case with a thick solution of Ivory soap, glycerin and water.

The protector cases should be kept well painted in order to prevent corrosion. Particular
attention should be taken to repaint any places where the paint may be marred or scr atched off
during or subsequent to installation. Recommendations for paint to be used will be furnished
upon request.

A. Cover Gasket Replacement

1. Multi-bolt Enclosure

When replacing the gasket on the enclosure, remove the old gasket comp letely and clean
flanges of all foreign material to insure a good bond when cementing new gasket in
position. When gaskets are ordered as a supply part, complete installation instructions,
together with an approved cement, will be shipped with the material.

2. Quick Opening Enclosure

a. Remove cover from box. For flat-spring-type hinge remove four screws which

secure hinge to front of cover. On boxes with sliding bolt-type hinge, remove
cover by removing cotter pins and washers which hold cover to hinge bolt.

b. Place cover in horizontal position with inside of cover facing upward.

c. Remove old gasket material and clean all foreign material from gasket retainer.

d. Select proper length gasket as follows:

Protector Description Gasket Length in Inches

1600 Amp. Transf. Mounted (small box) 133
1600 Amp, Transf. Mounted (large box) 141
1600 Amp, Separate Mounted 139
2000 Amp 159
3000 Amp 162

e. Pl ace gasket in retainer. Start with the gasket ends near the center of one of the

long sides of the cover. Place sections of the gasket in retainer as shown in Figure

19. Use wide nose pliers and soft mallet. Lubricating the gasket with hand cream
will aid in positioning the gasket. Continue placing the gasket in the retainer.
Work towards the gasket joint and be careful not to stretch, twist, or cut the
gasket. When in its final position the gasket should be free from waves or tool

35

marks. Wipe the hand cream from the ex posed gasket surface and apply talc to
keep the gasket from sticking to the housing.

f. Reassemble cover on the housing by following above procedure in the reverse

order.

Figure 19 – Door with Gasket

B. Changing Location of Operating Handle

The manual operating handle is usually located on the right side of the enclosure when facing
the protector, and will be supplied in this location unless otherwise specified. A bearin g is
furnished on both sides of the enclosure so that the location of the operating handle can be
changed to suit requirements. It is the usual procedure to have the air p ressure valve located
on the opposite side of the operating handle.

The breaker unit coupling can also be located on either si de of the manual shaft on the unit.
This coupling is secured to the shaft by means of a t aper pin which can be removed. The
couplings on the case and breaker unit are so arranged that they will not engage when
installing the breaker unit unless the breaker manual shaft and handle on case are in the open
position.

When the handle is to be changed to the opposite side proceed as follows. Remove the
handle and the indicator from the operating shaft, back out the locking screws in the packing
nut, remove the packing nut, remove the coupling from the operating shaft, remove the
operating shaft and remove the index plate.

Remove the sealing nut from the bearing on opposite side of the enclosure and assemble to
the bearing from which handle has been taken. Assemble the handle to the opposite side of
the protector enclosure in opposite sequence to the above.

36

The pin holding coupling to the operating shaft is shown for right side of the enclosure
mounting. When operating handle is mounted on left side of the enclosure the pin is inserted
in the hole of the coupling opposite to that shown.

If the packing removed from original bearing is in good condition, assemble in the new
bearing making sure that packing nut is drawn against the packing securely for proper
pressure seal and that the l ocking screws are se curely fastened to bearing to prev ent packing
nut from turning.

C. Packing

Packing nut is adjusted at the factory to provide an airtight seal, and further adjustment
should not be necessary. If, however, it is found necessary to tighten packing nut, remove
the handle and indicator, back out locking screws of packing nut and turn packing nut in
clockwise direction to improve airtight seal. If packing nut is tightened to within 1/16 inch
from bearing face, additional packing can be added or bearing repacked with recommend ed
packing.

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