78 • Motor and Soft Starter Protection
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8.
MOTOR AND SOFT STARTER PROTECTION
Protection functions are distinguished between adjustable protection functions and non-adjustable protection
functions.
Upon fault – motor stops,
Fault
LED lights and Fault Relay chances position.
The LCD shows TRIP: < fault description>. (for example: TRIP: UNDER CURRENT).
WARNING!
Upon any fault read carefully the
COMMISSIONING AND OPERATION
chapters in this manual before you try to identify the cause.
8.1
Adjustable Protection Functions
8.1.1
UNDER CURRENT
Trips the HRVS-DN when line current drops below the preset level for the preset time.
Check UNDERCURR. TRIP and UNDERCURR. DELAY settings; check line currents through L1, L2, L3.
For protection parameter settings refer to section
7.8.2 page 55.
8.1.2
O/C –SHEAR PIN
Trips the HRVS-DN when:
Instantaneously when current exceeds 850% of HRVS-DN FLC
While starting when current exceeds 850% of Motor FLA
While running when current exceeds 100-850% of Motor FLA with a programmable delay of 0-5 seconds.
Delay is overridden when current reaches 850% of HRVS-DN FLC.
Check that the motor is not stalled or jammed.
Check FLA, FLC settings.
Check motor and cable connections.
Perform a “Megger” test to check the condition of the motor and cables.
For protection parameter settings refer to section
7.8.2 page 55.
8.1.3
OVERLOAD
Trips the HRVS-DN when current exceeds the OVERLOAD TRIP level and the thermal register has filled up.
Check FLA, FLC and overload settings and check motor current, then wait at least 15 minutes to let the motor
and HRVS-DN cool down before restarting.
You may want to check motor THERMAL CAPACITY as displayed in the data page refer to section
7.8.1
page 54.
For protection parameter settings refer to section
7.8.2 page 55.
8.1.4
UNBALANCE CURRENT
Current Unbalance is the difference between the maximum and minimum values of the motor’s three line
currents divided by the motor’s maximum current or motor FLA, whichever is greater. A fault occurs when the
actual Unbalance is greater than the setpoint for a delay that exceeds the UNBALANCE DELAY.
For protection parameter settings refer to section
7.8.2 page 55.
8.1.5
GROUND FAULT
Trips the motor when Ground Current exceeds the preset GND FAULT TRIP for more than
GND FAULT DLY.
Check motor and cable connections.
Perform a “Megger” test to verify motor and cables condition.
For protection parameter settings refer to section
7.8.2 page 55.
