Frequently asked questions
On a new S-Flex installation, why does the motor run correctly in bypass and incorrectly in AFC?
FA170932
15 June 2022
Issue:
The motor runs forward in bypass but reverse in AFC.
Product Line:
S-Flex
Environment:
S-Flex with BYPASS feature
Cause:
None
Resolution:
In BYPASS mode, the power supply phase rotation passes straight through to the motor. In AFC mode, the VFD chops the AC power to DC and then creates an independent phase rotation on the Pulse Width Modulation output to the motor. Therefore, a new installation can initially result in various combinations of forward/reverse motor rotation in BYP/AFC modes. The Instruction Bulletin provides the preferred method to correct the motor rotation in both BYP and AFC modes. See the attached file.