contactor sizing

[arnettda]

I am installing a 3ph contactor on a motor load. It is used as an auxilary control to shut down a car wash. it will not be used under load or to start and stop the car wash. All normal disconects and starters are allready in place. It will be used for conveince so the single employee does not have to leave the store to turn off the carwash when temps drop. How do I size this contactor? As a disconect? Just off the nameplate?
Thanks

 

[james_mcquade]

I'm curious, if the contactor isn't going to have a load on it, just exactly how do you plan to turn the power
off to the carwash?

regards,
james

 

[arnettda]

I'm curious, if the contactor isn't going to have a load on it, just exactly how do you plan to turn the power
off to the carwash?

regards,
james

Maybe I should say the contactor will not be opened under load. The contactor will only be turned off when the car wash is not in use.

 

[ptonsparky]

Have open the control circuits and an El cheapo 15 amp will probably work. Line side of all motors will require a HP rating equal to or above you total motor load.

 

[hurk27]

Something does not sound to great with this idea, unless there is a camera system or other means to detect that a car is not in the middle of a wash cycle I can see a problem with this, now designing a simple interlock with this so that the car wash will keep running until the last car finishes might be something to add? most car washes around here incorperate a shut down in the customer controler where a customer inputs the code or money, this controler will also display that the car wash is out of service. this will not trap a customer in the car wash.

 

[nollij]

Have open the control circuits and an El cheapo 15 amp will probably work. Line side of all motors will require a HP rating equal to or above you total motor load.

This is the correct answer. I am not sure why you would want an entirely new contactor when this is an easy, cheap, and simple install. You could do this with a switch or button.