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I have 4 box fans in my barn that I want to be wired to a motion sensor. I've decided that I need to wire the motion detector to a relay and the relay from the outlet to the fans. Unfortunately I don't know what relay to get or from where.

I did find this but not sure it would be the right application..

http://www.grainger.com/Grainger/items/5LE35
 

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That relay will work as long as the total HP of the fans doesn't exceed 1/3. The 5LE36 will handle up to 1 HP.

You can also install a switch across the NO contacts to serve as a manual override.

Rob
 

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controlling 4 box fans through mo. sensor & relay!

I have 4 box fans in my barn that I want to be wired to a motion sensor. I've decided that I need to wire the motion detector to a relay and the relay from the outlet to the fans. Unfortunately I don't know what relay to get or from where.

I did find this but not sure it would be the right application..

http://www.grainger.com/Grainger/items/5LE35
If the current draw on the box fans is small (They might not be effective), you don't need a relay. You can hook the motion sensor directly (in series) to the fans. On the other hand, if they're large fans, you can't run the power supply from an outlet. The starting current will trip the breaker!:yes::no:
 

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Do you plug these fans into receptacles or are they hard wired? Box fans? What do you mean? The best way to control any motor loads is with a motor starter. You can get very good quality and very inexpensive motor starters. Try www.wegelectric.com Search for "CW" miniature contactors. Under $50.00 for one.
Just wire the sensor to engage the starter. The starter is just like a switch. If you go with a 3 phase starter you will have three NO contacts assigned for the motor and one NO relay you can also use for a motor under 10 amp. This way you only need one. They are designed to start 3 phase motors, but you can use each individual pole for each individual fan. However, all the fans will come on at one time. If you need independent control, you need a starter for each motor. The neutral does not need to be switched. Someone here with drawing software can post a drawing for you, how to hook it up.

These starters/contactors are just as cheap as relays. Relays work the same way and can be used if you like.
 

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silly34-I'll not second guess what you do with your "stuff" and your business, but why would you want to wire these fans up to a "motion sensor"? I'm just trying to understand what would cross the "motion sensor" to turn the fans on/off? Thanks, David
 

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silly34-I'll not second guess what you do with your "stuff" and your business, but why would you want to wire these fans up to a "motion sensor"? I'm just trying to understand what would cross the "motion sensor" to turn the fans on/off? Thanks, David
Livestock require ventilation just like we do. Especially Hogs and chickens.
 
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