Multidrive Modules; Protecting The Motor Cables Against Thermal Overload; Protecting The Motor Against Thermal Overload; Protecting The Motor Against Overload Without Thermal Model Or Temperature Sensors - ABB ACS880 Electrical Planning Instructions

34 Electrical planning guidelines

Multidrive modules

The drive has an overload protection as standard when the supply unit, inverter units and
other units are sized and installed correctly. See the appropriate hardware manuals.

Protecting the motor cables against thermal overload

￭
The inverter unit protects the motor cables against thermal overload when the cables are
sized according to the nominal output current of the inverter unit. No additional thermal
protection devices are needed.
WARNING!
If the inverter unit is connected to multiple motors, use a separate overload
protection for each motor cable and motor. The drive overload protection is tuned
for the total motor load. It may not detect an overload in one motor circuit only.
North America: The local code (NEC) requires an overload protection and a
short-circuit protection for each motor circuit. Use, for example:
• a manual motor protector
• circuit breaker, contactor and overload relay or
• fuses, contactor and overload relay.

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 motor thermal protection model supports thermal memory retention and speed sensitivity.
The user can tune the thermal model further by feeding in additional motor and load data.
The most common temperature sensor types are PTC or Pt100.
For more information, see the firmware manual.
Protecting the motor against overload without thermal model or
￭
temperature sensors
Motor overload protection protects the motor against overload without using motor thermal
model or temperature sensors.
Motor overload protection is required and specified by multiple standards including the US
National Electric Code (NEC) and the common UL/IEC 61800-5-1 standard in conjunction
with UL/IEC 60947-4-1. The standards allow for motor overload protection without external
temperature sensors.
The protection feature allows the user to specify the class of operation in the same manner
as the overload relays are specified in standards UL/IEC 60947-4-1 and NEMA ICS 2.
The motor overload protection supports thermal memory retention and speed sensitivity.
For more information, see drive firmware manual.