Can a contactor installed between the VFD output and the motor be used to start and stop the motor while the VFD remains running?
Resolution:
No. Using a contactor between the VFD and motor for normal Start/Stop control is not recommended.
Opening or closing an output contactor while the VFD is actively supplying the motor can interrupt or reconnect the VFD's pulse-width modulated (PWM) output. This can cause improper operation and may potentially damage the VFD output stage or motor.
For normal operation:
- Use the VFD's Start/Stop commands to control the motor.
- Do not use an output contactor to routinely cycle the motor ON and OFF while the VFD is running.
- A contactor installed between the VFD and motor should be used for motor isolation or other applications specifically permitted by the drive documentation, rather than as the primary Start/Stop control.
- Always refer to the installation and programming documentation for the specific Altivar model when an output contactor is required.
If this article does not answer your question, check out our FAQ database that has answers to more commonly asked questions:
Frequently Asked Questions - Schneider Electric (se.com)
If this FAQ did not solve your issue, you can call us at 1-888-778-2733 Option 2 and then 4 or e-mail us atdrive.products.support@se.comto create a case with our Technical Support Team.
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