Motor Rotation 5

[joan271273]

Usually I swap any two leads to correct a motor rotation issue during start up process.
In the case of a VFD I can only do this correction between the VFD and the motor, is this correct.

 

[gordonl]

For a typical drive this would be correct because the incomming AC is converted to DC before being inverted back to the VF AC out to the motor. So to change what the motor sees from the inverter the cables between the drive and motor need to swap.

 

[buzzp]

Typical, thats where you would change to get the correct phase rotation.
Some drives have this feature built in so no cable swapping would be necessary.

 

[Danfossegypt]

it is absolutely correct
in your VFD you can activate the reverse key
or you can have a switch to change direction for you

 

[ozmosis]

Addition to previous post:It is usually advisable for the output cables to be swapped than to change direction with a parameter or DI on the VFD. This prevents problems if somebody in the future should happen to do a factory reset on the drive and omit to record that phase rotation has been selected. It just makes it foolproof.

 

[davidbeach]

Watch out for VFDs with maintenance bypass contactors, the AC circuit on both sides of the drive needs to rotate in the same direction.

 

[jraef]

I agree wholeheartedly with sed2developer. Resetting to factory defaults is a common service tool when someone gets in trouble programming, and that is something easilly missed. Swap the wires on the VFD output cables (but see below).

I too would have brought up davidbeach's comment had he not beat me to it. I can't tell you how many trouble calls I have fielded because the user swapped the VFD output leads, but then the motor ran backwards when the bypass contactor was turned on! If you drive has them, you need to swap both the VFD output AND the line input cables. As gordonl said, the VFD does not know or care, but the bypass contactor does.

"Venditori de oleum-vipera non vigere excordis populi"

 

[edison123]

sed2 and davidb'd posts have good common sense for which they get stars.

sorry, jraef you were a mite late.

 

[jbartos]

Suggestion: I concur with postings suggesting an interchange of motor feeder leads between the VFD and motor.
Many VFDs have AC-DC-AC conversion that mandates it. In some AC-AC power electronic converters without the bypass switch, it would be possible to interchange the input leads.

 

[jraef]

Comment on the above post:
" In some AC-AC power electronic converters without the bypass switch, it would be possible to interchange the input leads." If by "power converter" you mean a current source inverter, I agree, but don't think that enough of those are still sold new to risk the possible confusion. 99.99999% of inverters sold now are PWM, and swaping input leads will do nothing for the motor.

"Venditori de oleum-vipera non vigere excordis populi"