11.1 Main Contactor Fail Protection
11.1.1 Operation
The Main Contactor Fail (MCF) protection operates if the Main Contactor (MC) fails to function by
either:
1. Failing to open when required. This is achieved by comparing the state of the main contactor (via
the Main Contactor Input MCI) against the state of the MCR relay output. This test provides
“Frozen Contactor Protection”.
2. Failing to maintain insulation across the contacts when the contactor is open. The Cable
Connecting Module is used to measure the voltage on the load side of the contactor. If this
exceeds 10% of the rated line voltage, a trip will occur. This test provides “Loss of Vacuum
Protection”.
A main contactor fail trip causes the CBR relay to de-energise, which trips the circuit breaker. An
internal battery backed flag in the IPD Relay is also tripped. A LED on the front panel of the IPD Relay
begins to flash.
The “MCF” LED on the Remote Display Module is illuminated and the open collector output on the
relay is switched on to provide remote monitoring if required.
11.1.2 Back EMF Parameter
Test 2 is inhibited immediately after the main contactor opens to allow for back EMF voltages
generated by some motors to dissipate. The inbuilt time is adjustable from 2 to 20 seconds (See
Section 13, User Adjustable Settings).
11.1.3 Resetting a Trip
To reset the flag, access to the relay is necessary. In the case of flameproof equipment the power has
to be removed in accordance with AS1039. The reset button is accessible through the front fascia of
the relay and must be pressed for 1 second.
11.2 Under-Voltage Trip
Under-voltage protection is enabled as soon as the main contactor is closed (indicated by closing the
MCI input). If any of the phase voltages drop below the selected trip setting of the nominal line voltage
for 800ms then the outlet is stopped. This is recorded in the event log as “uVOLT Trp”.
The trip level is selectable from 20% to 80% in 10% increments (Level 8, Position 4) on the Remote
Display Module.
Line voltages from 415V, 1000V, 3300V or 110V are configured when the appropriate CCMD/CCMA
Cable Connecting Module is selected in the Group 1 Settings (Level 8, Position 4) on the Remote
Display Module.
An Under-Voltage trip does not require a reset operation.
11.3 Voltage Metering
The cable connecting interface module (CCMD/CCMA) is also used to provide line voltage metering.
The outgoing line voltages for each of the 3 phases are displayed as a % of the selected rated line
voltage on the Remote Display Module (Level 4, Position 1). The maximum reading is 120%.
Line voltages from 415V, 1000V, 3300V or 110V are configured when the appropriate CCMD/CCMA
Cable Connecting Module is selected in the Group 1 Settings (Level 8, Position 4) on the Remote
Display Module. This parameter is also used in determining the cable fault leakage levels.
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