Halcohead
Stainless
- Joined
- Apr 10, 2005
- Location
- Bay Area, Ca
Is there anything wrong with running two different (but identical make/spec) motors off of one VFD?
The VFD will only ever drive one motor at a time, and both motors will always be fully stopped when switching the VFD from driving one motor to the other. The motors and VFD are going on a lathe, which for various reasons would benefit from having separate motors for backgear and open-belt operation.
Assuming this is okay, would there be anything wrong with using solid-state relays (SSRs) to implement the switch between the motors? I've heard some SSRs don't liked to be switched under zero load. Would zero-crossing SSRs work for this application? Do SSRs have a problem with noise in the VFD output or regenerative braking loads?
If it matters, the motors are nominally 7.5hp 1750 rpm, with VFD output frequency from 10-125Hz using sensorless vector control.
The VFD will only ever drive one motor at a time, and both motors will always be fully stopped when switching the VFD from driving one motor to the other. The motors and VFD are going on a lathe, which for various reasons would benefit from having separate motors for backgear and open-belt operation.
Assuming this is okay, would there be anything wrong with using solid-state relays (SSRs) to implement the switch between the motors? I've heard some SSRs don't liked to be switched under zero load. Would zero-crossing SSRs work for this application? Do SSRs have a problem with noise in the VFD output or regenerative braking loads?
If it matters, the motors are nominally 7.5hp 1750 rpm, with VFD output frequency from 10-125Hz using sensorless vector control.