Where do I ground my compressor at the pressure switch and motor?

I have a 1970 Sears Utility Air Compressor Model# 106.153780.


It is a 2HP, 150psi, twin cylinder, high pressure commercial capacity, 7.8cfm @ 40psi.

I bought it second hand, it is in great condition, except that the line and motor wiring was dry rotted and needed replaced.

The motor wire has 2 legs only, black and white. The line wire has 3 legs, black, white, and green. This is where I got lost. When I took the cover plate off the motor, the diagram on back shows 2 wires only but notes that motor must be grounded. The replacement wire I am using has all 3 legs. I dont know where the grounds need to be connected at the motor and at the pressure switch.

Also the motor tag says 230 volts and 10.6 amps. Should I use a 2-pole 15amp, 20amp breaker, or something else?
Thanks in advance, gary

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Mar 25, 2014
wiring power
by: Doug in s.d.ca

What your a/c guy said makes perfect sense - for an a/c guy.

a/c is more than just a compressor - you usually have a fan or two starting up along with the compressor(s), so a higher load.

There may be an electric code involved, too.

It really depends. search for "ampacity voltage drop" and you'll likely find "advanced voltage drop calcaultor - Electrician2.com"

Use the calculator, and you'll see what you need. use say double the current (22A) and double the length to see that either a 15 or 20A breaker with 12 gage wire will be plenty, unless you have a very long run from your breaker panel to the compressor. voltage drop should be less than 3%.

Bear in mind that a typical breaker can carry 100% load for years, and 150% for maybe an hour or so, and probably 200% for a minute or so, so that isn't usually a problem. Voltage drop (and reduced power available to the motor) IS.

You probably should call your local government entity and get an inspector's recommendation, especially if you do this right and get a permit and inspection (recommended).

Have fun.

Mar 25, 2014
Amps and Oil Capacity
by: Gary

Sorry for the add on questions but I just don't have a manual for this so hopefully this should get me up and running. Could you tell me what the engine oil capacity is? Not doubting your knowledge, but I may as well tell you what a htg/ac tech that was here the other day said. He told me to use a twin 30A breaker with 10/2 wire. Does that make any sense to you? Its a 1970 Sears single stage 230V, 2HP, 10.6A, 60 cycle, 150psi, and 7.8cfm @ 40psi. And since I don't have it in front of me, you told me to use a twin 15 or 20A breaker and 12/2 w/grd? What he said sounds like overkill and taking a chance of burning it up, but again, im no electrician.
Again, thanks for your help and I will let you know how it goes. Gary

Mar 24, 2014
amps
by: Doug in s.d.ca

That is about right - for 120V mains.

At 240, it's closer to half that.

15 should hold, but again, you can go 20 if it makes you more comfortable.

Personally, I'd go 15, because I'd rather have the motor cut out sooner than later if something goes weird.

And your tag says 11A, right?

Let us know when you're done, would you?

Good luck and have fun!

Mar 22, 2014
Breaker Size
by: Gary

I had previously read and forgot that breaker size should be about 4amps per 1/3 HP. Mine being 2HP that would put it at about 24amps. If that is truly the case, should I use a twin 30amp breaker?
Thanks, Gary

Mar 17, 2014
ground and AC supply
by: Doug in s.d.ca

Depending on distance, at least 12Ga wire from a twin 15A breaker should hold, but you might want to go 20A.

The ground can go to any part of the motor base or other convenient location. They sometimes go to a frame screw on the motor.

The ground need not go to the pressure switch,

You may want to run the power cord to a box, then on to the pressure switch using 2-wire cable, and the ground separately to the motor, depending on your layout and aesthetics.

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What is the compressor motor rpm supposed to be on Model 106.153540

by Bill
(Seattle)

I have a Sears 1 hp Model 106.153540 twin cylinder compressor. What is the motor rpm supposed to be?

1750rpm or 3450rpm.?

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Mar 17, 2014
motor speed
by: Doug in s.d.ca

If you can't find a spec (I had no luck) you can't go too wrong with the 1750. It has more torque to start than the 3450.

If it is supposed to be 3450, then all you lose is pump speed, and you can ramp that up with a smaller pulley on the motor, if need be.

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sears model 919.156780 rpm of motor and direction of rotation

My old sears model 919.156780 2h.p. compressor motor grounded. I need to get a new motor the nameplate from the motor is missing. Could you tell me the correct rpm and rotation???? I have the owners manual since I bought this new in 1978 but does not give this info . THANKS

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Dec 22, 2013
Manual for this same compressor
by: David

I've searched through the internet for the manual for this model. PLEASE, would you mind scanning the complete manual for me or something? I can't find this anywhere!

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manual and info for Sears model #106-171941

by Steve
(RI)

Sears model# 106.171941

Sears model# 106.171941

Sears model# 106.171941
Sears model# 106.171941
Sears model# 106.171941

Just acquired a Sears model# 106.171941 vintage air compressor that looks almost new, and runs perfectly. Looking for any manuals, parts lists, any kind of support for user info as well as planning for the future, possibly by buying parts before they are no longer available. This unit is 4 hp, 240 volt, 20 gallon horizontal tank, cast iron 2-cylinder pump. Any and all help appreciated.

___________________
Update from Steve:

An update on this unit- I was able to determine that it was made by Campbell-Hausfeld (by the 106 prefix) and emailed C-H to ask if they had any info. They sent me the attached owner's manual which you may want to post. There are also some parts available thru Sears. I couldn't find out how old it is, but I would guess maybe 30 or more years old.

This compressor seems in excellent shape, with almost no use, apparently it lived in a basement and the original owner just ran a hose up to his garage to pump up his car tires. To my mind, it's much more substantial than anything of comparable size on the market now- two of us strained to lift it into my Blazer. The frosting on the cake was the cost- $100. I think the 240 volt requirement was a drawback for possible buyers.

Regards,
Steve

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Mar 29, 2014
Manual
by: Dave

I'm in need of this manual/parts list/any info also. If you could forward to me, it would be greatly appreciated!
petey@olypen.com

Mar 22, 2014
Manual
by: Anonymous

Could you send me the manual? I just received a compressor just like this and can't seem to find a manual anywhere.

thanks, Dan
dobrien40@hotmail.com

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