Posted 22 August 2008 - 06:41 AM
Posted 22 August 2008 - 08:59 AM
Welcome to the forum.
Yes, when the voltage is removed from the motor operating at full speed, there will be voltage generated by the rotating rotor field in the stator field.
This voltage will decay exponentially as the rotor field decays.
The duration of the voltage generated is a function of the time constant of the rotor circuit. High efficiency rotors have longer time constants. This could delay the brake for up to half a second under normal situations, but if there is static power factor correction permanently connected to the motor terminals, it could be considerably longer.
I would agree with the recommendation of the use of a "brake" contactor if such a delay is critical.
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