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 183).
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 inductively to other
conductors in the control cable and form a risk of malfunction in other parts of the system.
Install the protective component as close to the inductive load as possible. Do not install
protective components at the relay outputs.
Guidelines for planning the electrical installation 63
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