40 M OT O R CO N T R O L A N D P R O T E C T I O N U N I T M 1 0X U S E R G U I D E
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05. Protection functions
The module provides full protection for motors
by supervising three voltage phases, three
current phases, earth fault current, PTC sensor,
startup time, the state of contactors and the
state of the main switch.
Response of protection functions is based on the
parameters given by the user. The operation of
separate functions is independent, thus
protection functions can be active at the same
time but the one which indicates the situation
first will give a trip for the motor.
According to the application, all kinds of
protection can be enabled, disabled by the upper
level system or MCU setup tool, and the
protection characteristics can be adjusted.
Protection module offers the following
protection and supervisory functions:
Protection type
Overload protection √ √
Stall protection √ √
Long start protection √ √
Phase failure protection √ √
Unbalance protection √ √
Underload protection √ √
Noload protection √ √
Earth fault protection √ √
PTC protection √
Undervoltage protection √
Start limitation protection √ √
Phase sequence Protection √ √
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Overload protection
Thermal overload protection (TOL) protects the
motor against overheating.The motor thermal
condition is simulated by a calculation. The result
of the calculation is stored in a thermal register
and can be reported via operator panel or
fieldbus interface.
Calculation is accomplished in a different motor
operation conditions, principle presented below.
Thermal increase and decrease are simulated by
TOL protection function for running and stopped
motor.