Emerson ASCO 336 Operator's Manual
Operator’s Manual ASCO 336 / 337
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Operator’s Manual
336 /337 Generator Paralleling System
DANGER
!
DANGER is used in this manual to warn of a
hazard situation which, if not avoided, will result in
death or serious injury.
WARNING is used in this manual to warn of a
hazardous situation which, if not avoided, could
result death or serious injury.
CAUTION is used in this manual to warn of a
hazardous situation which, if not avoided, could
result in minor or moderate injury.
WARNING
!
CAUTION
!
300 Series Power Control System
Refer to the outline and wiring drawings provided
with the 336 / 337 for all installation and connection
details and accessories.
Refer to the Controller User’s Guide for status
display messages, time delays, pickup and dropout
settin
s, and adjustments.
Rating Label
Each 336/337 PCS contains a rating label to define the loads
and fault circuit withstand/closing ratings. Refer to the label
on the transfer switch for specific values.
In a non-redundant system, that is, the load current is more
than one generator’s full load current and the generators are
being paralleled to provide more power to the load, the CTTS
current rating must be equal to or greater than the sum of the
two generator’s full load amps.
If the application is a redundant system, that is, the load
current is equal to or less than the full load amps of one
generator and the generators are being paralleled for
redundancy, the 336 or 337 rating must be equal to or greater
than the full load current of the biggest generator. In addition,
the output of the CTTS unit must be protected by an over
current device, like a circuit breaker, equal to or less than the
CTTS rating label.
WARNING
!
Do not exceed the values on the rating label.
Exceeding the rating can cause personal injury or
serious equipment damage.
Table of Contents
page
INSTALLATION ............................................... 3
FUNCTIONAL TEST .................................... 5-8
OPERATIONAL TESTING ........................ 9-10
FEATURES & OPTIONS ......................... 11-13
PROTECTIVE RELAY FUNCTIONS ............. 14
TESTING & SERVICE ................................... 15
INDEX ............................................................ 16
381333-427 A
381333-427 A ASCO Power Technologies Page 1
ASCO 336 / 337 Operator’s Manual
300 Series PCS Family of Products
The ASCO 300 Series Power Control System (PCS) is a
family of affordable and feature-rich products for paralleling
generators, controlling loads, and connecting generators to the
utility power system or grid. Transfer switch based or circuit
breaker based power switching options are available to meet
the requirements of all applications. The PCS 300 Series
control system is an integrated platform that provides
sequencing, synchronizing, generator load sharing, protective
functions, power management, and many other industryleading features, all while minimizing costs.
Upper
Customer
Terminal
CTs
CTTS
Transfer
Switch
CTs
Lower
Customer
Terminal
Block
Typical 336 Series PCS H-design 800-1200 ampere
336 / 337 PCS
The ASCO 336 / 337 PCS utilize the ASCO Power
Technologies industry-leading and time-proven Closed
Transition Transfer Switch (CTTS) mechanism to parallel two
generators per CTTS unit. The 336 manages the first two
generators of any system. The 337 can be added to manage
the third and fourth generators of a four generator system.
Due to the fault currents available, usually four generators is
the limit of a 336/337 PCS system. There are alternatives
within the 300 Series for paralleling more generators: co nt act
ASCO Power Technologies for more information.
A 337 may be added later as long as the electrical power
infrastructure is compatible. Options must be the same in a
336 and 337 for proper operation.
Controller
Operator
Interface
Terminal
OIT
Page 2 ASCO Power Technologies 381333-427 A
Operator’s Manual ASCO 336 / 337
E
Automatic Control System
The 336 / 337 is an automatic control system that may start
and/or stop generators and operate the transfer switch at any
time to maintain power to the load.
WARNING
!
NOTIC
Protect the transfer switch from construction grit
and metal chips to prevent malfunction or
shortened life of the transfer switch.
Line Connections
Proper precautions must be taken, including tag out
/ lock out procedures, to ensure personnel safety.
Installation
The system is factory wired and tested. Installation requires
mounting, connecting service cables, and connecting generator
control and generator circuit breaker control circuits.
System installation and startup by ASCO Power
Technologies is recommended.
An experienced licensed electrician must install the system.
The supporting foundation for the enclosure must be level and
straight. Refer to the applicable enclosure outline drawing
included with the system for all mounting details including
door opening space.
If bottom cable entry is used, the foundation must be prepared
so that the conduit stubs are located correctly. Refer to the
enclosure outline drawing for specified area and location.
Provide cable bending space and 1 inch minimum clearance to
live metal parts. When a concrete floor is poured, use
interlocking conduit spacer caps or a wood or metal template
to maintain proper conduit alignment.
Refer to the outline and mounting diagram and mount the
transfer switch according to details and instructions shown on
the diagram. Mount it vertically to a rigid supporting
structure. Level all mounting points by using flat washers
behind the holes to avoid distortion of the transfer switch.
NOTICE
Supporting Foundation
Mounting
Refer to the wiring diagram provided with the transfer switch.
All wiring must be made in accordance with the National
Electrical Code and local codes.
DANGER
!
De-energize the conductors before making any line
or auxiliary circuit connections. Be sure that the
Generator 1 and Generator 2 line connections are
in proper phase rotation. Place the engine
generator starting controls in the OFF position.
Make sure engine generators are not in operation.
Testing Power Conductors
Do not connect the power conductors to the transfer switch
until they are tested. Installing power cables in conduit, cable
troughs, and ceiling-suspended hangers ofte n req ui res
considerable force. The pulling of cables can damage
insulation and stretch or break the conductor’s strands. For
this reason, after the cables are pulled into position, and before
they are connected, they should be tested to verify that they
are not defective or have been damaged during instal l a ti on .
Connecting Power Cables
After the power cables have been tested, connect them to the
appropriate terminal lugs (if provided) on the transfer switch
as shown on the wiring diagram provided with the transfer
switch. Make sure that the lugs are suitable for use with the
cables being installed. Be careful when stripping insulation
from the cables; avoid nicking or ringing the conductor.
Remove surface oxides from cables by cleaning with a wire
brush. When aluminum cable is used, apply joint compound
to conductors. Tighten cable lugs to the torque specified on
rating label.
381333-427 A ASCO Power Technologies Page 3
ASCO 336 / 337 Operator’s Manual
E
Generator Circuit Breaker Control Circuits
The generator circuit breaker control connections are located
on customer terminal block. Connect signal wires to
appropriate terminals as specified on the wiring diagram.
Generator circuit breaker
The generator circuit breaker provides the overcurrent (short
circuit) protection for the system and functions as a back-up to
protect/isolate the system upon a fault during the loss of AC
control power. It does not matter if the generator circuit
breaker is manually operated close or electrically operated
close, but it must have a shunt trip and auxiliary contacts.
The control system has a dry contact (CTBx:19 to CTBx: 20,
rated at 8A, 30VDC or 8A, 250VAC, tripping duty) available
for shunt tripping the generator circuit breaker. This contact
must be connected during installation.
There is an option to have wire break monitoring of this shunt
trip coil. This requires (1) the shunt trip coil to be 24Vdc, (2)
supplied from the same source as the control system (normally
the generator batteries), and (3) not connected to any other
tripping circuit devices. This wire break system functions by
passing a small amount of current thru the breaker trip coil; if
this current gets too low, a wire break is assumed. If any other
devices are connected, for example indicating lights or other
trip devices, the wire break function may not work. The
maximum resistance of the trip coil circuit that this function
will work is 100 ohms. That is, if the circuit resistance exceeds
100 ohms, this function will alarm a wire break. Default from
the factory is this feature is not enabled; ASI may enable it
during startup.
If the generator circuit breaker is open the control system
needs to know that this gen-set is not available. This requires a
normally open dry contact (52/a: closed when the circuit
breaker main contacts are closed) to be wired to the control
system, CTBx:9 to CTBx:10. There should be no other
connections to this circuit. This is a contact input, wetted by
internal 24VDC (interrogation voltage) from the controller
power. If the generator circuit breaker is open, this generator
is not available and the Power Management option will not
include this generator in the gen shed/gen add program.
CTBx: x is the generator number.
Gen1 is CTB1, Gen 2 is CTB2.
Grounding different generator DC controls
Generators paralleled by the 336/337 system do not have to be
the same size or even manufacturer. However, different DC
grounding schemes may not be compatible with each other.
Optional DC to DC isolators can be added to the DC Control
Power circuit to prevent circulating currents and/or
unintentional grounds.
NOTIC
Optional DC to DC isolators are recommended for
all applications.
If all the generators utilize the same type of grounding – for
example, the negative pole of the batteries are all solidly
grounded – and the grounding system installation is good, this
may not be necessary. But, by example, if one generator uses a
solidly grounded DC scheme and the second generator uses a
floating DC system or the integrity of the DC ground
connection(s) is/are not known or reliable, then this option is
required. If the all generators use the same grounding scheme
for the DC control power and the installation is perfect, this
optional feature may not be needed.
Changing settings
Most settings require a password to change. There are 3 levels
of passwords: Customer, Service, and Master. The Customer
password is 1111 and will allow access to the nominal settings
like voltage, frequency, generator KW, etc. The Service level
password is known to authorized ASI service representatives
and is required for startup. The Master level password is
reserved for factory use.
While it is possible to program the controller from the keypad,
most users will find it more efficient to use a laptop computer,
an A/B USB cable (see Figure 1), and the free Utility Software
available from the 336/337 website. In the Designer’s
Reference Handbook are directions for installing the software,
connecting the controller to the laptop, and making changes to
the settings.
If the generator circuit breaker opens for any reason, the CTTS
will open when AC control power is available. The control
system will alarm and not be available until the generator
circuit breaker is closed again and the alarm is reset. If this is
the only generator running and the circuit breaker trips, the
CTTS may be closed. See AC Control Power Circuit
description.
Figure 1. A/B USB cable for programming controller.
Page 4 ASCO Power Technologies 381333-427 A
Operator’s Manual ASCO 336 / 337
Functional Test
The functional test consists of three checks: manual
operation, voltage checks, and electrical operation.
Do these checks in the order presented to avoid
damaging the transfer switch.
A maintenance handle is provided on the transfer switch for
maintenance purposes only. Manual operation of the transfer
switch should be checked before it is energized (before it is
operated electrically). Note the contact position indicators.
Do not manually operate the transfer switch until all
power sources are disconnected: open both
generator circuit breakers and all load circuit
breakers.
NOTICE
1 – Manual Operation
WARNING
!
Left side of the
transfer switch
Maintenance handle
Generator 2
contact shaft hub
Clip
Generator 1
contact shaft hub
Hubs shown with
Generator 1 source
contacts open and
Generator 2 source
contacts closed.
Figure 2. J-design transfer switch maintenance handle.
1. After deenergizing both power sources, open the enclosure
door. Locate and remove the maintenance handle. Select
either H-design or G-design. See Figures 2 and 3.
J & H-design see Figures 2 & 3
The maintenance handle is stored in clips on the left side
of the transfer.
G-design see Figure 4
The maintenance handle, hub, and pin are stored on the
center frame of the transfer.
2. Install the handle into the hole in the molded hub. Move
the handle up or down as shown to manually operate the
transfer switch to close and reopen the contacts. It should
operate smoothly without any binding. If it does not, check
for shipping damage or construction debris.
J & H-design see Figures 2 & 3
The transfer switch has two contact shaft hubs Install the
maintenance handle into the hole in the molded hub. The
upper hub operates the Generator 2 contacts. The lower
hub operates the Generator 1 contacts.
G-design see Figure 4
Install the hub (with pin) onto the shaft. Insert the
maintenance handle into the side hole in the hub. Push in
the shaft to operate the Generator 1 contacts. Pull out the
shaft to operate the Generator 2 contacts.
3. After checking manual operation, return all transfer switch
contacts to the open position. Generator 1 and Generator 2
contacts must be open. Check contact position indicators.
4. Remove the maintenance handle and store it on the transfer
switch in the place provided.
J & H-design see Figures 2 & 3
Store the maintenance handle in the clips on the left side of
the transfer.
G-design see Figure 4
Store the maintenance handle, hub, and pin on the center
frame of the transfer.
Note: If Generator 1 and Generator 2 connecti ons a re reve rsed
this operation is also reversed.
WARNING
!
Verify that the maintenance handle has been
removed and stored properly before electrically
operating the transfer switch.
381333-427 A ASCO Power Technologies Page 5
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