Using a contactor between the drive and the motor
Implementing the control of the output contactor depends on how you select the drive to
operate. See also section Implementing a bypass connection (page 84).
When you have selected to use
• vector control mode and motor ramp stop,
open the contactor as follows:
1. Give a stop command to the drive.
2. Wait until the drive decelerates the motor to zero speed.
3. Open the contactor.
When you have selected to use
• vector control mode and motor coast stop; or scalar control mode,
open the contactor as follows:
1. Give a stop command to the drive.
2. Open the contactor.
WARNING!
When the vector control mode is in use, never open the output contactor while the
drive controls the motor. The vector control operates extremely fast, much faster
than it takes for the contactor to open its contacts. When the contactor starts
opening while the drive controls the motor, the vector control will try to maintain
the load current by immediately increasing the drive output voltage to the maximum.
This will damage, or even burn the contactor completely.
Implementing a bypass connection
If bypassing is required, employ mechanically or electrically interlocked contactors between
the motor and the drive and between the motor and the power line. Make sure with
interlocking that the contactors cannot be closed simultaneously. The installation must be
clearly marked as defined in IEC/EN 61800-5-1, subclause 6.5.3, for example, "THIS
MACHINE STARTS AUTOMATICALLY".
WARNING!
Never connect the drive output to the electrical power network. The connection
can damage the drive.
Protecting the contacts of relay outputs
Inductive loads (relays, contactors, motors) cause voltage transients when switched off.
ABB highly recommends to equip inductive loads with noise attenuating circuits (varistors,
RC filters [AC] or diodes [DC]) in order 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.
84 Guidelines for planning the electrical installation
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