Do you consider a VFD a motor controller?

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rich000

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In trying to meet the requirements for motor disconnect in sight of motor, would you consider a VFD to be a controller?

In our installation, the 480V VFD is in site of the motor. The VFD is fed from a breaker in another location. This is a regular molded case breaker.

After reading and re-reading 430.103, it does not seem to meet the intent.

- The disconnecting means is not in site of the controller.
- It is not over 600V
- The breaker serving the VFD is a regular molded case breaker (i.e. it does not have a permanent lockable means).

Again, if the VFD is not a controller and only a disconnect, then this would be a moot point. But I interpret the VFD to be a controller.

Any thoughts?
 
I think I found my answer. The "controller/VFD" has the disconnect built in. Since it is insight of the motor, we are okay. I guess I was just thinking that the disconnect was part of the controller and would still require an external disconnect.
 
A VFD is not a disconnect, but is a controller. If you have a disconnect as part of a controller it is probably a disconnect and controller in one cabinet just like a combination starter has a disconnect and controller all in one package.

The start stop controls are not a disconnecting means but simply controls. A disconnect must physically open the circuit and not be able to be automatically operated to reclose the circuit. I say this because it could automatically open the circuit in cases like a shunt trip breaker used as the disconnect. May be a little more to it than that for the really technical people, but that is good place to start.
 
I was going to say ABB has a pretty slick setup with an integral rotary disconnect and VFD all-in-one. But it looks like that's what you got. Carry on....:D
 
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