Torque Reduction During Stopping
During stopping when the motor brake closes and the motor current is immediately removed a noise can sometimes be heard in the lift cabin, to help solve this problem parameter P4-17 can be adjusted so that the current is ramped down rather than switching the current sharply off, this is used in Gearless Permanent Magnet motor applications.
Increasing this value reduces audible noise, setting too high can result in reduced torque and rollback during stopping.
If the value of P4-17 is set to 0 then the function is disabled.
The image below shows where the Torque Reduction during stopping takes place on the travel curve for a Gearless Permanent Magnet Motor.
Important
When operating with an Induction motor the drive uses an internal value of 0.1seconds and P4-17 has no effect.
Parameter Number | Parameter Name | Units | Default | Available Settings | Access | Change During Run | Scaling | Size (Bytes) | CAN Register | CAN Sub Index | Modbus Register |
|---|---|---|---|---|---|---|---|---|---|---|---|
P4-17 | Torque Reduction time during stopping | sec | 1.0s | 0.0 ... 10.0s | RW | Y | 1 = 0.1 s | 1 | 21A1h | 0 | 417 |
Setting 0 means function is disabled. This parameter helps in reducing the noise in the lift car when the motor brake is applied due to the immediate removal of current. Increasing this value reduces audible noise, setting too high can result in reduced torque and rollback during stopping.
This parameter has no effect when operating in an IM control mode (P4-01 = 0 or 1) and the torque reduction time is fixed at 100ms.