Implementing the Power-loss ride-through
Implement the power-loss ride-through function as follows:
• Check that the power-loss ride-through function of the drive (inverter unit) is enabled.
See the drive firmware manual.
• Make sure that the control of the main contactor/breaker either keeps the contactor
closed over the short power break, or closes it after the break automatically.
WARNING!
Make sure that the automatic re-connection of the input power does not cause
any danger. If you are in doubt, do not implement the Power-loss ride-through
function.
WARNING!
Make sure that the flying restart of the motor will not cause any danger. If you are
in doubt, do not implement the Power-loss ride-through function.
￭ Cabinet-installed drives with main contactor (option +F250)
With external uninterruptible control voltage (option +G307), the main contactor remains
closed in power-loss situations. If the power-loss situation lasts so long that the drive trips
on undervoltage, it must be reset and started again to continue operation.
Implementing the control of a contactor between drive and
motor
The control of the output contactor depends on how use the drive, ie: which motor control
mode you select, and which motor stop mode you select.
When you use the DTC or vector motor 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 use the DTC or vector motor control mode and motor coast stop, or the scalar
motor control mode, open the contactor as follows:
1. Give a stop command to the drive.
2. Open the contactor.
WARNING!
In the DTC or vector motor control mode do not open the output contactor while
the drive controls the motor. The DTC and vector motor control operate faster than
the contactor opens its contacts. If the contactor starts to open when the drive
controls the motor, the DTC or vector control tries to maintain the load current and
increases the drive output voltage to the maximum. This can cause damage to
the contactor.
38 Electrical planning guidelines
To Next Page
Loading...
