# Pressure Switch for compressor



## Wirenuting (Sep 12, 2010)

jmoney9130 said:


> A friend picked up a 10hp 208/240v air compressor. The pressure switch has the wire going to the contactor but there is another wire im not sure where it goes


Single phase, 3 phase? Home or job site? Who made it and what model?
Are you a journeyman?


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## jmoney9130 (Sep 12, 2013)

yes im a journeyman. This is a three phase unit. it is a commercial job, an auto shop. im doing a favor for a friend who is setting up a new shop


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## B4T (Feb 10, 2009)

The pressure switch should be connected to terminals 1&3 on the motor starter...


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## Wirenuting (Sep 12, 2010)

jmoney9130 said:


> yes im a journeyman. This is a three phase unit. it is a commercial job, an auto shop. im doing a favor for a friend who is setting up a new shop


Ok, here is a link to Ingersoll Rand.
You should be able to get an idea for it. 

http://www.ingersollrandproducts.com/am-en/support/manuals-and-technical-publications

With out knowing the model, I would hate to take a guess. But it's basically just a start circuit. They only break one side of the coil. 
Depending on the model, it could be a board controlled unit and then they make it more of a PITA.


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## papaotis (Jun 8, 2013)

B4T said:


> The pressure switch should be connected to terminals 1&3 on the motor starter...


 is that so common that you dont have to check a wiring diagram?:001_huh:


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## jmoney9130 (Sep 12, 2013)

ok. in the contactor i have my line. a load going to the motor which is wired for low volt. also out of the contactor is a load going to the pressure switch. your saying the the other wire out of the pressure switch goes to # 1 and 3 in the motor?


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## Bbsound (Dec 16, 2011)

Some compressors of that size run the control circuit through an oil level switch on the side of the compressors block.


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## B4T (Feb 10, 2009)

papaotis said:


> is that so common that you dont have to check a wiring diagram?:001_huh:


Yes... you can find it listed under "two wire control" in the cut sheets..


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## jmoney9130 (Sep 12, 2013)

i know that its an older speedaire model. 10hp and is rated for 208/240 three phase


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## Wirenuting (Sep 12, 2010)

Like this?


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## B4T (Feb 10, 2009)

jmoney9130 said:


> ok. in the contactor i have my line. a load going to the motor which is wired for low volt. also out of the contactor is a load going to the pressure switch. your saying the the other wire out of the pressure switch goes to # 1 and 3 in the motor?


That is correct.. it is your control circuit..


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## Wirenuting (Sep 12, 2010)

jmoney9130 said:


> i know that its an older speedaire model. 10hp and is rated for 208/240 three phase


Look at the Ingersoll rand link I posted,, you will find the manuals there for it..


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## jmoney9130 (Sep 12, 2013)

hey thanks wirenutt. can i get a link to that


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## Wirenuting (Sep 12, 2010)

jmoney9130 said:


> ok. in the contactor i have my line. a load going to the motor which is wired for low volt. also out of the contactor is a load going to the pressure switch. your saying the the other wire out of the pressure switch goes to # 1 and 3 in the motor?


Do you know the coil voltage?
Don't hook it up if the old one had a transformer or board to control it.. 
If this is something your friend picked up, was it new or a used one from another site?


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## Wirenuting (Sep 12, 2010)

jmoney9130 said:


> hey thanks wirenutt. can i get a link to that


I posted it on the 5th comment. 

But here it is again for ya.

http://www.ingersollrandproducts.com/am-en/support/manuals-and-technical-publications

Better
http://www.irtechpubs.com/index.cfm?fuseaction=view.main&type=Compressed Air&cat=206&sub=933


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## jmoney9130 (Sep 12, 2013)

he picked it up used from some tire shop. its a pretty old unit i couldnt get the model number off it. a large green speedaire, if your familar. i believe the coil voltage is 120v 60hz


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## Wirenuting (Sep 12, 2010)

jmoney9130 said:


> he picked it up used from some tire shop. its a pretty old unit i couldnt get the model number off it. a large green speedaire, if your familar. i believe the coil voltage is 120v 60hz


Ok, if the coil is 120 and the motor is 208 3 phase, then it sounds like you need a transformer, it should be in the unit mounted control box..


Here is a better link,,

http://www.irtechpubs.com/index.cfm?fuseaction=view.main&type=Compressed Air&cat=206&sub=933

They have redone their support site.. I have a better link to the manual sections, but it's on my phone at work.. I'm Ipading it tonight.


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## jmoney9130 (Sep 12, 2013)

I will take a better look first thing. maybe i may have to get a multivolt contactor. My main concern was the second wire on the pressure switch. thanks for your help bro


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## Wirenuting (Sep 12, 2010)

jmoney9130 said:


> I will take a better look first thing. maybe i may have to get a multivolt contactor. My main concern was the second wire on the pressure switch. thanks for your help bro


The contactor can carry many voltages, but the coil voltage is normally not variable.. But most contactors do come apart and you can change the coil.. 
I know the link I posted is a PITA to look thru, but if you can't find a model number, take some time and dig thru the manuals the have.. Yours will pop up.. 
Tomorrow I'll see if my phone has a better link to their manuals.


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## Wirenuting (Sep 12, 2010)

Post a picture tomorrow, lots of smart people are here and might be able to ID it quicker..


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## Wirenuting (Sep 12, 2010)

Just saw that SpeedAir is a Grainger house brand. 
Here is a site that talks about it. 

http://www.about-air-compressors.com/speedaire.html#ixzz0z51YKNQ2

The Ingersol rand site won't help you. 
But here is a Quincy site. Maybe between the 2 you'll find the info you need. 
But post a pictures anyway. 


http://www.revbase.com/TagTeam/Client/UserJump.asp


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## glen1971 (Oct 10, 2012)

jmoney9130 said:


> A friend picked up a 10hp 208/240v air compressor. The pressure switch has the wire going to the contactor but there is another wire im not sure where it goes


So this switch has two wires, and one is connected, and you need to know where the other goes? The one connected, does it go to the coil? Is there an "Off/On" or "Off/Auto" swtich on it? Where is it getting it's control voltage from?


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## Wirenuting (Sep 12, 2010)

glen1971 said:


> So this switch has two wires, and one is connected, and you need to know where the other goes? The one connected, does it go to the coil? Is there an "Off/On" or "Off/Auto" swtich on it? Where is it getting it's control voltage from?


Sounds like he wasn't sure of the coil voltage. 
Hopefully he can grab a model # or a couple of pics for us today.


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## glen1971 (Oct 10, 2012)

Wirenuting said:


> Sounds like he wasn't sure of the coil voltage.
> Hopefully he can grab a model # or a couple of pics for us today.


Gotcha.. A pic is always worth a 1,000 words...


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