protection is tuned for the total motor load. It may not trip due to an overload in
one motor circuit only.
Protecting the motor against thermal overload
According to regulations, the motor must be protected against thermal overload and the
current must be switched off when overload is detected. The drive includes a motor thermal
protection function that protects the motor and switches off the current when necessary.
Depending on a drive parameter value, the function either monitors a calculated temperature
value (based on a motor thermal model) or an actual temperature indication given by motor
temperature sensors. The user can tune the thermal model further by feeding in additional
motor and load data.
The most common temperature sensors are:
• motor sizes IEC180…225: thermal switch, for example Klixon
• motor sizes IEC200…250 and larger: PTC or Pt100.
See the firmware manual for more information on the motor thermal protection function.
Protecting the drive against ground faults
The drive is equipped with an internal ground fault protective function to protect the unit
against ground faults in the motor and motor cable. This is not a personnel safety or a fire
protection feature. The ground fault protective function can be reduced with parameter 31.20
Earth fault..
ï¿ Residual current device compatibility
The drive is suitable to be used with residual current devices of Type B.
Note:
The EMC filter of the drive includes capacitors connected between the main circuit and the
frame. These capacitors and long motor cables increase the ground leakage current and
may cause fault current circuit breakers to function.
ï¿ Implementing the Emergency stop function
For safety reasons, install the emergency stop devices at each operator control station and
at other operating stations where emergency stop may be needed. Design the emergency
stop according to relevant standards.
Note:
Pressing the stop key on the control panel of the drive does not generate an emergency
stop of the motor or separate the drive from dangerous potential.
Implementing the Safe torque off function
See chapter The Safe torque off function.
Implementing the undervoltage control (power-loss
ride-through)
See ACQ80-04 standard control program firmware manual (3AXD50000170654 [English].
60 Planning the electrical installation
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