Eaton LBS Series Installation, Operation And Maintenance Manual

I.B. 48030

Cutler-Hammer

Instructions for Installation, Operation, and Maintenance of
Type LBS Medium-Voltage Disconnect Switch rated 7.2kV

Fig. 1 Typical LBS Switch with Auxiliary Fuse Compartment

Read and understand these instructions before attempting any
Installation, Operation or Maintenance of an LBS switch.

Cutler-Hammer

Power Distribution and Assemblies Division
Arden NC 28704

Effective February 2001

PURPOSE

This instruction book is expressly intended to cover the
operation and maintenance of LBS load interrupter
switches. It does not purport to cover all possible
contingencies, variations, and details that may arise
during operation or maintenance of this equipment.

If further information is desired regarding this product,
contact the local Cutler-Hammer sales office.

TABLE OF CONTENTS Page
Section 1 - Introduction.

1.1 Basic Description and Application 3

1.2 Switch Identification 3

1.3 Safety Features 3

1.4 Safe Practices 4

Section 2 - Receiving, Handling and Storage

2.1 Receiving 4

2.2 Handling 4

2.3 Storage 4

Section 3 – Inspection Before Startup 4

Section 4 - Operation

4.1 Mechanical Safety Interlocks 5

4.2 Switch Operation 6

4.3 Fuse Replacement 7

Section 5 - Maintenance

5.1 Inspection Procedure 7

5.2 Alignment Procedures 8

5.3 Replacement Procedures 9

5.4 Lubrication 10

Section 6 Hardware Torque Chart 11

For the location of your nearest Cutler-Hammer
distributor, call toll free 1-800-525-2000

Page 2

SECTION 1 - INTRODUCTION

1.1 Basic Description and Application

The Type LBS switch is a three-pole, manually
operated, quick-make, quick-break switch available in
both 600 ampere and 1200 ampere continuous ratings.
This device is used primarily as a disconnect switch in
AC power systems with maximum voltages up to 7200
volts and may be supplied with or without fuses.

A Type LBS switch without fuses is capable of closing
under fault conditions and interrupting magnetizing and
load currents, but is not intended to interrupt fault
currents. When supplied with fuses, a Type LBS switch
may be used to provide fault protection up to the
interrupting rating of the fuses. Refer to Table 1 for
ratings.

LBS Switch Ratings

Description

Switch with internal
fuses (450E max
@5kV, 350E
max @ 7.2kV)

Switch with 600E
and 750E fuses
(5kV max)
Switch with 1100E
and 1350E fuses
(5kV max)
Unfused (7.2kV
max) 1200A 61kA 38kA N/A

*1200A rating is for NEMA 1 enclosure with vented covers.
NEMA 3/12 rating (without vents) is 1000A.

Cont. and
Break
Current

600A 40kA 25kA 50kA

1200A 61kA 38kA 40kA

1200A* 61kA 38kA 31.5kA

Fault­Close
(un­fused)

Short­time (2
sec)
Current

Fused
Interrupting
Rating
(Symm)

Table 1 Ratings

Each Type LBS switch is designed for operation in an
enclosure and should not be operated under load with
the enclosure door open.

1.2 Switch Identification
A rating nameplate is located on the handle coverplate

(behind the handle access door) of each type LBS
switch. Contained on this nameplate are the switch
type and ratings as required by industry standards. A
unit nameplate located near the upper left corner of the
medium voltage door contains the factory’s general
order number. This number should be given to the
Cutler-Hammer Sales Office if a question should arise
concerning the switch or if renewal parts are required.

DANGER!

Exceeding the nameplate ratings of an LBS sw itch
may cause property damage, severe injury, or
death.

Do not apply an LBS switch beyond its nameplate
ratings.

1.3 Safety Features
The Type LBS load interrupter switch is manufactured

with several built-in interlock provisions and safety
features to reduce hazards and provide proper
operating sequences:

1. A mechanical interlock prevents opening the
main door when the switch is in the closed
position.

2. An additional interlock prevents inadvertent
closing of the switch when the front enclosure
door is open.

3. The switch design includes provisions for
padlocking the switch in the open or closed
position.

4. Mechanical indicators with labels show
whether the switch is open or closed.

5. Optional key interlock provisions may be
provided for Main-Tie-Main and other
configurations. Refer to the specific order
drawings to determine if key interlocks have
been provided.

6. A grounded metal safety screen is located
behind the medium voltage door. The screen
prevents inadvertent contact with live parts yet
allows full-view inspection of the switch blade
position.

Danger!

Type LBS switches are often energized by a back-fed
condition that allows the blades to be energized with the
switch in the open position. The line-side break jaws
are also likely to be energized with the switch open.

All power sources must be isolated and locked out
before removing the safety screen.

1.4 Safe Practices

Only qualified electrical workers with training and
experience on medium voltage circuits should be
permitted to work on this equipment. They should be

familiar with the work to be performed, the safety
equipment required, and hazards involved.

Read and understand these instructions before
attempting any assembly, operation, or maintenance of
an LBS switch.

Disconnect all power sources before making any
adjustments or performing maintenance.

WARNING!

Defeating or disengaging safety interlocks on an
LBS switch that is properly installed and connected
to a power source may result in property damage,
bodily injury or death.

Do not defeat or disengage any safety interlocks when
the switch is connected to any power source.

Never energize an LBS switch without the arc chutes
and phase barriers installed.

Always be sure that all hardware is in place and
properly tightened before putting an LBS switch into
operation after any maintenance operation. The contact
and blade hardware must be tightened as described in
Section 5 to provide the correct contact pressure while
maintaining free operation of the blades.

SECTION 2 – RECEIVING, HANDLING AND
STORAGE

2.1 Receiving

When receiving an LBS switch, a visual inspection
should be performed immediately upon receipt of the
switch and before removing it from the truck. Shipping
papers should be checked to be sure that all boxes or
other accompanying pieces have been received. If any
damage or shortages are evident, a claim should be
filed at once with the carrier and the nearest Cutler­Hammer sales office should be notified.

2.2 Handling
An LBS switch is insulated for high voltages and must

be protected at all times against damage during
handling.

2.3 Storage
If it is necessary to store an LBS switch before

installation, keep it in a clean, dry location with ample air
circulation and heat to prevent condensation. Like all
electrical apparatus, an LBS switch contains insulation
that must be protected against dirt and moisture.

Page 3

SECTION 3 – Inspection Before Initial Energizing
of an LBS Switch

NOTE!

Each switch is properly adjusted at the factory before
shipment. However, vibration and mechanical stresses
imposed by transit and installation can adversely affect
switch adjustment; therefore, a final inspection is
essential before energizing. If this inspection reveals
the switch has come out of adjustment, the switch
should be re-adjusted according to alignment
procedures in Section 5.2.

Inspection procedures require closing and opening the
switch with the main door open. This requires override
of the switch safety interlock as described in Section

5.3.1 and must be accomplished before energizing.

6-5/8”
gap

d. With the switch closed, the upper spacers of

the main blades should rest 3/16"+/-1/16"
above the bottom of the depression of the
stationary break jaw (see Fig. 4).

e. With the switch closed, each main blade

assembly should engage the break jaw such
that the back of the blades is between flush
and 1/8” from flush with the top of the vertical
surface of the break jaw (see Fig. 10).

1/16” to
1/8” gap

Fig. 3 Drive Rod Links and Shaft Ears Alignment

Fig. 2 Main Blade Adjustment

Inspection Procedure:
a. With the switch in the open position (see Fig.

2) the distance between the edge of the main
blade and the closest point of the break jaw
should be 6-5/8"+/- 1/8".

b. Main and flicker blades must be in proper

alignment with break jaws and arc chute
openings respectively. This can be checked
by closing the switch and then partially
opening it using the maintenance hub as
described in Section 5.1.3.

c. In the closed position the drive rod links and

shaft ears must be 1/16" to 1/8" over toggle
when checked with a straight edge (see Fig.

3).

Special
Torque
setting per
Sec 5.2.6

3/16”
gap

Fig. 4 Main Blade Spacer Adjustment

f. When LBS fuse mountings are supplied,

check to ensure the fuse mountings are
securely fastened and fuses are properly
clamped in place. Ensure all threaded
fasteners are torqued to the appropriate value
in section 6.0.

h. Wipe away any dust or dirt that may have

accumulated in the switch or fuse
compartments, paying particular attention to
insulators and insulating material.

Page 4

i. A final thorough inspection should be made to

ensure that no tools or other objects have
been accidentally left inside the enclosure.

SECTION 4 - OPERATION

4.1 MECHANICAL SAFETY INTERLOCKS

WARNING!

Defeating or disengaging safety interlocks on an
LBS switch that is connected to a power source
may result in property damage, bodily injury or
death.

Do not defeat or disengage any safety interlocks unless
all power sources have been disconnected and locked
out.

The LBS switch is equipped with switch interlocks and
door interlocks as described in section 1.2.

Shaft
Intlk

Mechanism
Intlk

Fig. 5 Door/Switch Interlocks

4.1.1 Door/Switch Mechanism Interlock

This mechanical interlock prevents inadvertent closure
of the switch if the enclosure door is open. When the
door is closed, a bracket fastened to the inside of the
enclosure door causes the interlock latch to move out of
the blocking position (see Fig. 5).

4.1.2 Door/Switch Shaft Interlock

This interlock prevents the door of the enclosure from
being opened when the switch is closed. If the switch is
closed, a hook welded to the operating shaft engages a
bracket fastened to the inside of the switch enclosure
door, thus preventing the door from being opened. (See
Fig. 5.)

4.1.3 Key Interlocking, LBS Switch

Key interlocks for one or two key, Kirk brand type “F”
locks (or other manufacturers’ equal) with one-inch bolt

Page 5

projection are optionally available on the LBS switch.
Refer to the specific order drawings for a description of
operation for these interlock schemes, when provided.

4.2. Switch Operation

CAUTION!

Attempting to operate an LBS Switch with a key
interlock bolt extended will result in equipment
damage and may also expose a person to bodily
injury or death.

The key must be inserted into the interlock and rotated
to retract the locking bolt before operating an LBS
switch.

Make certain that the switch door is fully
closed and the ¼-turn latches fully engaged
before operating the switch.

Operating the switch without the main door and ¼­turn latches fully closed could result in damage to
the door or door interlock.

To close or open an LBS switch, the operating handle is
inserted into the handle casting and rotated up or down
as appropriate. This charges the compression spring,
and as the spring lever goes over-toggle, the stored
energy of the spring is transferred to the shaft which
snaps the switch open or closed. The blades thus
move at a predetermined speed that is independent of
the operator.

When the LBS in mounted in the bottom compartment
of an Ampgard structure, care should be taken to insure
that the operator’s hand is not located between the
handle end and the floor. Grasp the operating handle as
shown in Figure 6 to insure safe, reliable operation of
the switch. The operator should stand clear of the
handle while opening or closing the switch. Care
should be exercised to avoid dropping the handle.

Store the handle in the clips provided on the handle
coverplate (see Fig 6).

CAUTION!

Handle
Storage
Clips

Fig. 6 Handle Operation

The quick-make mechanism provides power to
overcome blowout forces that occur if the switch is
closed into a fault. These forces are not transmitted to
the operating handle since it is not rigidly connected to
the blades. The switch can therefore be safely closed
under short circuit conditions within its fault-close rating.

Load interruption is accomplished by flicker blades and
contact fingers located inside a DE-ION arc chute. On
opening the switch, the main blades open first and all
current is shunted through the spring-loaded flicker
blades. Further travel of the main blades cause the
flicker blades to snap out of their contact fingers. Arcing
takes place within the arc chutes between the contact
fingers and flicker blades.

4.3 Fuse Replacement

WARNING!

When accessing fuses, failure to assure that the
fuses are de-energized may result in equipment
damage, bodily injury, or death.

Make sure that all power sources are de-energized
before attempting to access the fuses.

When specified, the Type LBS switch is supplied with
Cutler-Hammer Type CLE or HLE current limiting power
fuses. Fuse puller, part number 6391D55G01, is
supplied with fuses rated 450 amps or less to aid in the
insertion and removal of the fuses. Instructions for
using the fuse puller are mounted on the inside of the
switch enclosure door. Fuses rated 600E to 1350E are
of the bolted type and are mounted in auxiliary
compartments.

SECTION 5 - MAINTENANCE

An LBS switch should be thoroughly inspected prior to
initial energizing. Every 100 operations or yearly
thereafter a cursory inspection to clean, lubricate, and
check for signs of wear and tear, damage, etc., is
recommended as described in section 5.1. If any
problems are discovered they should be corrected by
following procedures in sections 5.2 and 5.3. After 30
interruptions at the rated current or after the switch has
been exposed to fault currents, the switch should be
thoroughly inspected at the first opportunity. If the
switch has been moved or otherwise subjected to
mechanical strain, inspection procedures described in
Section 3 should be performed.

The rated mechanical life of the LBS is 500
operations.

5.1 Inspection Procedure

WARNING!

Failure to completely disconnect the switch from all
power sources prior to inspection or maintenance
may result in severe injury or death.

An LBS switch must be completely disconnected from
all power sources before performing inspection.

5.1.1 Main Blade and Flicker Blade Contact
Inspection

Check main blades and flicker blades for arc erosion.
Severely damaged blade assemblies should be
replaced as described in Sections 5.3.1 and 5.3.2.

If flicker blades become rough from arc erosion, they
may be smoothed with a few light strokes of a fine file.
No attempt should be made to file out pit marks. Do not
use any abrasive material for cleaning. If questionable,
don’t file the flicker blades.

The main blade current carrying contact surfaces must
not be filed. Opening and closing the switch will keep
them clean. If main blade current carrying contact
surfaces are burned, they must be replaced.

5.1.2 Arc Chute Inspection

Page 6

Inspect arc chute sides for cracks or erosion and
replace if damaged. Use a flashlight to examine the
arcing contacts inside the arc chute. If contacts are
found to be burned or pitted over half of their surface, or
if the contacts are out of alignment, the arc chute
should be replaced.

CAUTION!

Slow closing or slow opening the switch using the
maintenance hub may result in bodily injury if care
is not taken to hold the operating handle firmly.

Be sure to hold the handle firmly while performing slow
closing or slow opening operations.

5.1.3 Flicker Blade Engagement Check

First, close the switch. Next, insert the removable
handle in the pipe-like maintenance hub welded to the
switch shaft (see Fig. 7) and slowly open the switch.
The flicker blades should remain engaged in their
contact fingers while the main blades open. When the
main blades clear the break jaws, they will hit a stop on
the flicker blade brackets and start the flicker blades out
of their contact fingers. The flicker blades will then snap
open from the forces in their charged torsion springs.

Inspect the tightness of the bolts securing the flicker
blades to their mounting brackets. Inspect the flicker
blade mounting bracket to insure that does not pivot up
and down on its mounting bolt. Tighten the bolt if
pivoting is observed. Do not overtighten. To verify that
the mounting bracket bolt has not been overtightened,
push the flicker blade to the rear. It should rebound
smoothly.

Check interphase barriers for carbon or metallic
deposits. Replace if deposits are present.

5.1.5 Cleanliness check
Wipe away any dust or dirt that may have accumulated

on the switch parts, paying close attention to insulators
and insulating material.

5.1.6 Mechanical Operation Check
Close and open the de-energized switch at least three

times to check the performance of the operating
mechanism.

5.2 Alignment Procedures

Check each of the following items for adjustment and
alignment. If out of adjustment and alignment, follow
the instructions given.

WARNING!

Failure to completely disconnect the switch from all
power sources prior to inspection may result in
severe injury or death.

The switch must be completely disconnected from all
power sources before performing inspection.

5.2.1 Override of Door / Switch Mechanism
Interlock

To close the switch with the door open, the interlock
must be disengaged. To close the switch, insert the
handle into the handle casting and push upward, at the
same time push the latch that is accessible through a
slot in the handle cover inward until the handle casting
clears the interlocking bolt. (See Fig. 8) To open the
switch, reverse this procedure, making sure that the
door interlock is fully depressed.

Maintenance
Hub

Fig. 7 Use of Maintenance Hub

5.1.4 Interphase Barrier Inspection

Page 7

Fig. 8 Override of Switch Interlock Safety Latch

5.2.2 Close-Open Stop Adjustment

t

Remove the handle mechanism cover by removing the
bolts securing the cover to the switch frame. Remove
the casting with the switch position indicators by
loosening 2 bolts. The adjusting bolts are now
accessible as shown in Fig 9. Adjustment is made by
loosening the lock nut and turning the bolt.

The bottom stop bolt adjusts the closed position. When
properly closed, the shaft rod ends should be slightly
over-toggle. Verify the adjustment by laying a straight
edge on top of the drive rod so that its end extends over
the shaft (see Fig. 3). If a 1/16" to 1/8" gap appears
between straight edge and drive rod, adjustment is
correct.

Upper
Stop Bolt

Lower
Stop Bolt

Fig. 9 Close-Open Stop Adjustment Bolts

Check to see that the blades are closing fully. To do
this, measure the distance from the upper switch
terminal pad to the outer edge of the main blade (See
Fig. 10). This dimension should be 3-5/16" to 3-7/16".
Should adjustment be required, loosen the bolt holding
the drive rod to the main shaft clevis and adjust the
blade travel. Re-tighten the bolt to 25 foot pounds.

3-5/16”
to
3-7/16”

Fig. 10 Proper Main Blade Engagement

Page 8

In the open position, clearance between the edge of the
main blade and the break jaw should be 6-5/8” as
described in Section 3 and Figure 2. The top stop bolt
adjusts this dimension (see Fig. 9).

If the switch is equipped with key interlocking, care must
be taken when replacing the switch mechanism cover to
ensure that it is properly repositioned. The key interlock
bolt must clear the open-closed indicating cam handle
casting when retracted.

5.2.3 Main Blade Alignment
It is important that the main blades be properly aligned

with the upper break jaw to insure smooth operation of
the switch. To align the blades and jaw after one or
both have been replaced, follow the procedure below:

Loosen the four hinge bolts and the two break jaw bolts.
Insert the removable handle in the maintenance hub on
the shaft and close the switch. (For safety purposes, the
switch will not fully close and will revert to the open
position if pressure on the handle is released). Hold the
switch in the closed position with the handle and tighten
the bolts on both the hinge and jaw to 25 foot-pounds.
Hold handle firmly throughout alignment process.

5.2.4 Arc Chute Alignment

Loosen the two arc chute mounting bolts. Adjust the
arc chute so that its opening is parallel to the main
blade. Tighten the mounting bolts enough to prevent
movement. Using the maintenance hub located on the
switch shaft (see fig. 7), slowly close the switch and
check that the flicker blade is in line with the arc chute
opening. If necessary, move the arc chute left or right
until it lines up with the flicker blade. Completely tighten
the arc chute mounting bolts and recheck the
alignment.

5.2.5 Vertical Position of Break Jaw
Close the switch. Check that the upper spacers of the

main blades are between 1/8”and 7/32” above the tops
of the break jaws. If they are not, loosen the bolts
holding the break jaw. Adjust as necessary. When
setting is correct, tighten bolts to 25 foot-pounds (see
Fig. 4).

5.2.6 Break Jaw Bolt and Hinge Contact Bolt
Tightness

The disk springs on the main blade assembly must
provide the necessary contact pressure between the
main blades and stationary mating parts when the
switch is closed (see Fig. 4). At the break jaw end, if
the elastic stop nut must be removed a sensitive torque
wrench used to set the proper contact pressure as
tabulated below.

Faul

-Close Rating, kA Inch-pounds of torque

asymmetrical
40
61

20
25

The elastic stop nut at the hinge end must be tightened
to a value of 20 inch-pounds on all switches.

It is critical that the bolts at both ends of the main blade
assembly be properly tightened. If the bolts are over­tightened, the switch may not properly open or close. If
the bolts are under-tightened, the blades will not make
a good electrical connection and the switch will
overheat. A resistance reading across each pole can
be used to verify that the blades are tight enough, but
will not indicate if they have been over-tightened. Ohm
readings between the top terminal pad and the bottom
terminal pad on each pole should not exceed 60 micro­ohms when the bolts are tight.

5.3 Replacement Procedures

WARNING!

Failure to completely disconnect the switch from all
power sources prior to inspection may result in
severe injury or death.

The switch must be completely disconnected from all
power sources before performing inspection.

5.3.1 Main Blade/Hinge Subassembly and Break

Jaw Replacement

Begin with the switch should be in the closed position.
Disconnect the drive rod link from the clevis on the main
shaft. Remove the four bolts holding the hinge
assembly to the lower terminal pad. The hinge, main
blade and flicker blade assembly is now free and may
be removed, along with the lower terminal pad.
Remove the two bolts holding the break jaw to the
upper terminal. Remove the old jaw. Replace the jaw
and finger tighten the two mounting bolts. Replace the
main blade and hinge assembly on top of the lower
terminal pad and finger tighten the four bolts. Align the
blade per paragraph 5.2.3. Tighten the jaw and hinge
mounting bolts. Lubricate per Sec 5.4.

Align flicker blade and arc chute per paragraph 5.2.4.
Check flicker blade function per paragraph 5.1.3. If
satisfactory, re-connect the drive rod link to the main
shaft clevis, being sure to reinstall the clinch spacer in
the large hole in the drive rod. Check the switch for
adjustments per paragraph 5.2.2 and 5.2.5. Perform
the pre-operation check (see Section 3).

5.3.2 Flicker Blade Replacement

Remove the locknut and bolt securing the flicker blade
assembly to the main switch blade. When re-installing,
made certain that the spring is installed against the stop

Page 9

pin. Verify by pushing the assembly back and
observing its return to the original position.

Flicker
Blade

Fig.11 Flicker Blade Assembly

5.3.2 Springs

The main spring is a large horizontally mounted
compression spring along the inside of the switch frame
on the operating handle side. For higher fault-close
ratings, there is also an auxiliary spring vertically
mounted and connected to the main shaft.

The main and auxiliary springs are not field replaceable.

5.3.3 Pre-Use Check
After completing any maintenance, the alignment

should be checked (See Section 5.2.). After completing
any alignment, the switch should be operated at least
three "close-open" operations to check for proper
performance. Insure that the break jaw has been
properly lubricated per Section 5.4.

5.4 Lubrication

Lubrication is critical to the proper operation of the
switch and should be performed every 100 operations
or yearly, during switch maintenance (see Section 5).
C-H conductive grease, part number 7274A48H02,
should be applied moderately to contact surfaces on

each break jaw (Fig 12). Avoid any lubrication on
insulation.

Failure to regularly lubricate the break jaws may result
in the failure of the switch to properly open or close.

Lubricant

Fig. 12 Break Jaw Lubrication

Section 6 - Bolt Tightness for Connections to
Terminal Pads

Use the following torque value for tightening bus joints.

Note: This table is for bus connections only. Use
the special torque values listed in the respective
sections for the main blades.

Torque Values in Foot-pounds for
Bolt Diameter

Diameter, inches .25 .31 .38 .50 .6

2

Nominal Torque 4 8 25 50 65

Page 10