Can I use a larger HP Variable Speed Drive to run a smaller HP motor?

Issue:
Motor is smaller than the available drive.

Product Line:
All Altivar (ATV) drives

Environment:
All Environments

Cause:
Motor and drive sizing does not match.  Motor is smaller HP than Drive.

Resolution:
YES.
In most cases a drive can control a motor with lower HP (and current) rating.

The motor nameplate information will have to be entered correctly to ensure proper control of the motor and that the overload protection is enabled.
In most cases the Overload protection adjustment range is the limiting factor.  If this parameter can not be set down to the motor FLA, an external overload relay will have to be provided.
When using small motors on a larger drive the Sensorless Flux Vector motor control modes may not work well.  Changing the motor control type to linear Voltage/Frequency is usually best.
Consult the programming manual for the drive being used for details on these parameter adjustments.
If working with an enclosed drive that has full voltage bypass, the Overload Relay in the bypass circuit may need to be changed if it's OL settings can not be adjusted down to the motor FLA.

NOTE that this does not pertain to Softstarts.   Softstarts will not work well with motors that are less than 40% of their continuous current rating.

Udgivet til:Schneider Electric Danmark