AuCom MVE series User Manual page 42

Motor Protection
Motor, System and Soft Starter Protection Mechanisms
•
The MVE incorporates extensive protection features to ensure safe operation of the motor, system and soft starter. Most protection
features can be customised to suit the installation. Use parameter group 4 Protection Settings to control the situation where the
protections will activate and parameter group 16 Protection Action to select the soft starter's response. The default response is to
trip the soft starter.
Protection Coordination

Check protection settings on the supply side of the starter to ensure correct coordination with the parameters of the soft starter.
When using fuse and main contactors, set the upstream circuit breaker protection parameters according to the ratings for fuse
and contactor. The contactor must not open if the current is above its maximum breaking current value. The fuse must act first or
the upstream breakers instantaneous trip level must be less than the contactor's maximum breaking current level.
If using circuit breakers only, set the soft starter's maximum instantaneous trip time < 150 ms. Always use a suitable external
protection relay with a circuit breaker to ensure instantaneous overcurrent trip functionality.
Voltage must not be continuously maintained on the phase arms while the motor is off. Short circuit protective equipment must be
installed in all cases.
Motor Overload Protection

The MVE offers thermal model motor overload protection which monitors the performance of the motor and calculates its
temperature in all states. This protection is based on the motor information programmed in parameter groups 1 and 9, and the
thermal model adjusts itself according to the motor's recent operating history (including temperature rise from previous
operation).
1
Motor Thermal Model Protection Set-up
•
To enable motor and starter protection using the motor thermal model, the soft starter must be programmed with accurate
information on the motor's characteristics.
1. Set parameters 1B
datasheet.
2. Use instantaneous overcurrent protection (parameters 4E, 4F) to provide protection for locked rotor situations. Refer to
individual parameters for details.
3. Use instantaneous overcurrent protection stage 2 (parameters 4U, 4V) to trip circuit breaker or main contactor in the
event of extreme overcurrent situations.
3
4
5
2
Current
Locked Rotor Time Locked Rotor Current
, 1C
1 Motor service factor
2 Locked rotor current
3 Motor failure curve
4 Motor thermal model protection curve
5 Typical motor operating current
Motor Service Factor
and 1D
MVE User Manual (710-17074-00G) |
CONTROLLER
according to the motor
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