Motor Control

[masterelect1]

Being from the Industrial side of the trade, I saw something recently which I am not familiar with. The elect contractor installed a 3 phase motor contactor w/ OL relay and fusible disconnect switch for a 7.5 hp motor @ 208 volts. He is using the disconnect switch to pull in the contactor, not a push button or selector switch as I am used to seeing. I do not like this method of controlling the motor, but I cannot find a violation in the code. Am I missing something?

Thanks, John

 

[jim dungar]

Being from the Industrial side of the trade, I saw something recently which I am not familiar with. The elect contractor installed a 3 phase motor contactor w/ OL relay and fusible disconnect switch for a 7.5 hp motor @ 208 volts. He is using the disconnect switch to pull in the contactor, not a push button or selector switch as I am used to seeing. I do not like this method of controlling the motor, but I cannot find a violation in the code. Am I missing something?

Thanks, John

There is no code violation in doing this. If the disconnect is HP rated then timing with the starter (which one closes last, which opens first) is not even a concern.

 

[mdshunk]

I do dock fans that way all the time. Saves the unnecessary expense of a pushbutton station or a more expensive combination motor starter. The only one's in the dock area that I have any "control power" pulling in the contactor are the one's the f/a bings on for smoke evac.