Question:
Why can there be a short start delay after controller enable when using the 8400SL, 8400HL and 8400TL in conjunction with asynchronous motors operated in 'Servo control ASM'?
Answer:
When operating asynchronous motors (ASM) in the 'Servo control ASM' motor control mode, after controller enable, the magnetising current has to reach a certain minimum value. Only after reaching the threshold, motor rotation will actually be started.
In connection with the brake control, this may erroneously lead to the impression that the time settings of the brake logic do not have any influence.
Depending on the electrical characteristics of the motors, the magnetisation phase of ASM can take several hundred milliseconds (small ASM) or up to some seconds (large ASM). The magnetisation time constant is determined by motor-specific parameters: (mutual inductance + leakage inductance) / rotor resistance.
Background:
Without appropriate magnetisation, the motor cannot generate the required torque.
As a result, hoists (active loads) could be sagging and translatory drives could not follow the drive quickly enough; if necessary, the following error monitoring function would respond.
Possible remedy:
For the 8400 TopLine and the 8400SL and 8400HL V10.0 and higher, the motor magnetising current threshold from which on, when reached, the motor will be actually started can be selected under the parameter C00918.
To start as soon as possible, the percentage threshold can, if necessary, be reduced under C00918, in extreme cases to 0%. In this case, you will, however, have to accept that the motor as a matter of principle cannot immediately provide its full torque with the above-described potential consequences (sagging, response of the following error monitoring function).
The parameter C00918 has not yet been implemented for 8400SL and 8400HL <= V6.x.
Search terms: Magnetising current; magnetisation; magnetising; delayed start; starting performance
