Ampcontrol Pty Ltd
– ABN 28 000 915 542
IPD USER MANUAL
IPDB014 Version 14
– SEP/2020
Uncontrolled Copy - Refer to Ampcontrol Website for Latest Version
Page 49 of 96
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A selection of 50 times effectively disables the thermal memory. With this selection, as soon as the
main contactor opens, the thermal model resets quickly so that a cold restart is achieved.
CAUTION!
Repeated restart attempts in this condition may damage the motor.
Typical fan cooled motor protection is based on a cooling multiplier setting of 0.4, however, for the best
protection consult your motor manufacturer.
The thermal model continues to simulate the motor’s thermal behaviour even if the power is removed
from the relay. When power is restored the thermal memory would be at the same level had there been
no loss of power.
The “OC Trip” Accumulator shows the state of the thermal model: 0% = Cold, 100% = Trip.
When a trip occurs the IPD Relay cannot be reset using the reset button until the accumulator is less
than 80%. For the purposes of an emergency restart on a hot motor, the thermal memory can be reset
by selecting Level 5, Position 3 on the Remote Display Module. The display shows:
ZERO THERM MEM?
RESET + LOCK[100]
The [100] indicates the current value of the trip accumulator. Operating the lock and reset buttons
simultaneously while the above display is being shown will zero the OC Trip Accumulator after 1.5
seconds.
Indication of the trip condition for motor overload is the same that occurs for an over-current trip.
10.3 Short Circuit Protection
The short circuit function has a definite time characteristic. If the current exceeds the selected level for
the pre-set time then a trip occurs.
The “SC” LED on the Remote Display Module is illuminated and the open collector output on the relay is
switched on to provide monitoring if required.
To reset the relay following a short circuit trip it is necessary to operate and hold the lock button closed
and then close the reset button.
The relay can be programmed so that a short circuit condition can trip either the “CBR” relay or the
“MCR relay. This can be achieved by selecting either relay at the “SC Relay” selection in the non-volatile
memory (Level 8, Position 5) on the Remote Display Module. Normally the “CBR” selection would be
used. If “MCR” is selected then the user must ensure that the interrupting device that is operated by the
short circuit trip output of the relay has sufficient current interrupting capacity at the system voltage for
the situation in which it is installed.
The short circuit trip level is adjustable from 3 to 10 times (full load current) in 0.5 increments. The trip
time is selectable from 20ms to 160ms.
CAUTION!
When “CBR” is selected for the Short Circuit trip it is important to
consider the S/C trip time in relation to the trip times for faults that trip
the “MCR” and could occur at the same time as the S/C (e.g. Earth
Leakage and Earth Continuity).