Two motors, one contoller

[eric9822]

I have an existing installation of a 1200 HP 2300V motor. A project manager that likes to think way outside of the box would like to install a backup for this motor but avoid the expense of adding another motor starter. His proposal is to add a "switch" at the location of the motors that would allow the existing starter to feed either motor one at at a time. Section 430.87 specifies that each motor shall have its own controller with a few exceptions, none of which says you have a transfer switch downstream of the controller, I would like to kill this idea quickly. My gut instinct says that by the time I spec out an adequate transfer switch and add the proper interlocking to prevent switching while the motor is running and prevent running both motors from running I will exceed the cost of a starter. The whole thing sounds ridiculous anyway. Is 430.87 enough to kill the idea?

 

[volt101]

I agree that I would want to kill this idea because if the cost is about the same for a transfer mechanism, why not just put in a back up controller, as you would end up with a better redundant system.....

 

[eric9822]

Yes thank you. I was hoping to get some feedback so I could kill it based on the code section. Looks like I am going to have to price it out and then kill it.

 

[mbeatty]

Yes thank you. I was hoping to get some feedback so I could kill it based on the code section. Looks like I am going to have to price it out and then kill it.

Sound like a good plan. :grin:

 

[lakee911]

I ran into a VFD once that had two constant speed starters and two motors attached to it. Each motor could be across the line or one on VFD and one or the other constant speed. Odd beast.