ABB ACS180-04S-03A7-1, Hardware Manual, Page: 59 / 192

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 161) .
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 from the drive
during maintenance work on the drive.
Implementing the control of a contactor between drive and
motor
Implementing the control of the output contactor depends on the motor control
mode and stopping method selected.
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.
WARNING!
If vector motor control mode is in use, do not open the output contactor
while the drive controls the motor. The motor control operates faster than
the contactor, and tries to maintain the load current. This can cause damage
to the contactor.
When you select the vector motor control mode and the motor coast stop mode,
you can open the contactor immediately after the drive has received the stop
command. This is the case also if you use the scalar motor control mode.
Protecting the contacts of relay outputs
Inductive loads (relays, contactors, motors) cause voltage transients when switched
off.
It is highly recommended that inductive loads are equipped with noise attenuating
circuits (varistors, RC filters [AC] or diodes [DC]) to minimize the EMC emission at
switch-off. If not suppressed, the disturbances can connect capacitively or
Guidelines for planning the electrical installation 59