ABB ACS380 Series, Hardware Manual

Page: 57 / 186

Planning the electrical installation 57
Implementing thermal overload protection
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Protecting the drive, and the input power and motor cables against
thermal overload
If the cables have the correct size for the nominal current, the drive protects itself and
the input and motor cables against thermal overload.
WARNING! If the drive is connected to several motors, use a separate circuit
breaker or fuses to protect each motor cable and motor against overload. The
drive overload 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 the regulations, the motor must be protected against thermal overload
and the current must be switched off when an overload is detected. The drive has 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 or an actual temperature indication given by motor
temperature sensors. The user can tune the thermal model by feeding in additional
motor and load data.
The most common temperature sensors are:
• For motor sizes IEC180…225: a thermal switch, for example, a Klixon.
• For motor sizes IEC200…250 and larger: a PTC or Pt100 sensor.
Protecting the drive against ground faults
The drive has a ground fault protection function that protects the unit against ground
faults in the motor and motor cable. It is not a personnel safety or a fire protection
feature.

Residual current device compatibility
The drive can be used with residual current devices of Type B.
Note: The EMC filter of the drive has capacitors between the main circuit and the
frame. These capacitors and long motor cables increase the ground leakage current
and can cause the fault current circuit breakers to function.
Implementing the emergency stop function
For safety reasons, install the emergency stop devices at each operator control
station and at other operating stations where an emergency stop may be needed.
Design the emergency stop according to the applicable standards.