ABB ACS880-17 - Protecting the Motor against Thermal Overload

Guidelines for planning the electrical installation 81
 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, eg. Klixon
• motor sizes IEC200…250 and larger: PTC or Pt100.
See the firmware manual for more information on the motor thermal protection, and the
connection and use of the temperature sensors.
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 in TN (grounded) networks. This is not
a personnel safety or a fire protection feature. The ground fault protective function can be
disabled with a parameter, refer to the firmware manual.
An optional ground fault monitoring device (option +Q954) is available for IT (ungrounded)
systems. The option includes a ground fault indicator on the drive cabinet door.
 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.
Implementing the emergency stop function
The drive can be equipped with a category 0 and 1 emergency stop function (option
+Q951, +Q952, +Q963, +Q964, +Q978 or +Q979). For safety reasons, install the
emergency stop devices at each operator control station and at other operating stations
where emergency stop may be needed.
Note: Pressing the stop key on the control panel of the drive, or turning the operating
switch of the drive from position “1” to “0” does not generate an emergency stop of the
motor or separate the drive from dangerous potential.
See the appropriate user’s manual for the wiring, start-up and operation instructions.
Option
code
User’s manual
Manual code
(English)
+Q951 Emergency stop, stop category 0 (using main contactor/breaker) 3AUA0000119895
+Q952 Emergency stop, stop category 1 (using main contactor/breaker) 3AUA0000119896
+Q963 Emergency stop, stop category 0 (using Safe torque off) 3AUA0000119908
+Q964 Emergency stop, stop category 1 (using Safe torque off) 3AUA0000119909
+Q978 Emergency stop, stop category 0 or 1 (using main contactor/breaker and Safe
torque off)
3AUA0000145920
+Q979 Emergency stop, stop category 0 or 1 (using Safe torque off) 3AUA0000145921