ABB ACS480, Hardware Manual, Page: 49 / 180

As an alternative, you can connect the sensor with basic insulation to the analog/digital
input(s) of the drive, if you do not connect any other external control circuits to the drive
digital and analog inputs.
3. You can connect a sensor to a digital input of the drive via an external relay. The sensor
and the relay must form a double or reinforced insulation between the motor live parts
and the digital input of the drive.
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 function is not a personnel safety
or a fire protection feature. See the firmware manual for more information.
￭ Residual current device compatibility
The drive is suitable to be used with residual current devices of Type B.
Note: As standard, the drive contains capacitors connected between the main circuit and
the frame. These capacitors and long motor cables increase the ground leakage current
and may cause nuisance faults in residual current devices.
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 the applicable standards.
You can use the Safe torque off function of the drive to implement the Emergency stop
function.
Note: Pressing the stop (off) 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 (page 147) .
Using a safety switch between the drive and the motor
ABB recommends to install a safety switch between the permanent magnet motor and the
drive output. The switch is needed to isolate the motor during any maintenance work on the
drive.
Implementing the control of a contactor between drive and
motor
The control of the output contactor depends on how you use the drive, that is, which motor
control mode and which motor stop mode you select.
When you select the vector motor control mode and the motor ramp stop mode, use this
operation sequence to open the contactor:
1. Give a stop command to the drive.
2. Wait until the drive decelerates the motor to zero speed.
3. Open the contactor.
Guidelines for planning the electrical installation 49