
Functions
5.10 Technological functions
Frequency inverter
134
Operating Instructions, 08.10. 2008, t.b.d.
5.10.1.4
Parameterizing a motor holding brake
The motor holding braking prevents the motor from rotating when the frequency inverter is
powered-down, e.g. when a load is lowered in a hoisting gear application. The frequency
inverter has internal logic to control a motor holding brake.
Commissioning the control logic of a motor holding brake
1.
Before commissioning, secure any dangerous loads (e.g. suspended loads for crane
applications)
–
Lower the load to the ground
–
Suppress the motor holding brake control, e.g. by disconnecting the control cables
2.
For hoisting gear applications, set the starting torque
Before the motor holding brake is opened, a torque must be established that prevents the
load from briefly sagging.
–
Check the magnetizing time P0346; the magnetizing time is pre-assigned when
calculating the motor data and must be greater than zero.
–
The minimum frequency P1080 should approximately correspond to the rated motor
slip r0330
3.
For hoisting gear applications, adapt the voltage boost to the load
–
Boost parameters P1310, P1311 - for V/f operation (P1300 = 0 to 3)
–
The mechanical brake is controlled using bit 12 ("Brake active") of status signal r0052
of the brake control. This signal is available at terminals A and B of the Power Module.
It is not sufficient to simply select status signal r0052 bit 12 in P0731 to P0733 (relay
outputs). To activate the motor holding brake, parameter P1215 must be additionally
set to 1.
4.
Parameterize the opening and closing times of the motor holding brake
It is extremely important that electromechanical braking is controlled with the correct
timing (brake release time, brake closing time, release time) to protect the brakes against
long-term damage. The exact values are provided in the motor catalog. Typical values:
–
Brake release times are between 35 ms and 500 ms
–
Brake closing times are between 15 ms and 300 ms
–
Release times are between 25 ms and 230 ms
When a motor with a built-in holding brake is commissioned, a "clicking" sound in the motor
indicates that the brake has been properly released.