Operator's Manual

ASCO 336 / 337 Operator’s Manual
Page 4 ASCO Power Technologies 381333-427 A
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.
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.
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.
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.
Figure 1. A/B USB cable for programming controller.
NOTIC
E
CTBx: x is the generator number.
Gen1 is CTB1, Gen 2 is CTB2.