Convert compressor motor from 110 to 220 volt (a/k/a/ 115/230v)

Old 06-05-13, 02:30 PM
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Convert compressor motor from 110 to 220 volt (a/k/a/ 115/230v or 120/240v)

This applies to air compressors equipped with a small GE air compressor motor.

The 110/220 conversion is Very Easy to do, but locating all of the information below was difficult and time consuming, so I'm posting it here for others' benefit.

I suspect the instructions below apply to any air compressor equipped with what apparently is known as a "small GE compressor motor," although I can only be certain with respect to my own compressor's motor, on which is pasted a white label marked "GE Motors" at the top left (next to the GE logo), over a red line, which is over a blue-lined chart stating: "MOD 5KCR49TN2235X", "V 115/230", "RPM 3450", "PART #MO-9062", and the words "AIR COMPRESSOR MOTOR".

On the right side of that same label is a schematic diagram showing how the wires are configured for both 115 and for 230 volt use. If you can "read" that schematic, it's essentially all the information you need to set up the motor itself.


In case you can't clearly understand the steps from the schematic, the "instructions" for converting the motor for 220 (or 230) volt use are:

--- Move the brown (P2) wire from Terminal 1 to Terminal 7.
--- Move the white (T2) wire from Terminal 3 to Terminal 1.
--- You're done!

In case you prefer it, a more detailed "step by step" follows:

1. Make sure there is no power to the compressor/motor (be sure the compressor is unplugged from the wall).

2. Remove the motor's access plate (you'll find this at the end of the motor nearest the compressor's On/Off switch). To remove it, just loosen the two screws holding it in place and then pivot the access plate off.

3. Look over what's exposed so you'll be able to perform the next steps. [You'll see that there are a number of wires plugged into Terminals on a black plastic wiring block and that at least one Terminal (#7) has no wire plugged into it at all. You also should see that there is a number embossed in the black plastic of the wiring block adjacent to most (though not all) of these Terminals. Each embossed number is used to identify the specific Terminal adjacent to it. However, these embossed numbers can be hard to see/read, so I've also tried to describe the location of each affected Terminal below.]

4. Find the brown wire marked "P2". [You should find it plugged into Terminal 1 (Terminal 1 is located on the LEFT side of the MIDDLE ROW of the wiring block). Note that Terminal 1 has two prongs (side by side), each of which probably has a wire plugged into it. The wire on the RIGHT prong of Terminal 1 should be the brown P2 wire.]

5. Unplug the brown (P2) wire from Terminal 1 and plug it onto the prong of Terminal 7 (Terminal 7 is located at the far RIGHT side of the MIDDLE ROW of the wiring block and should not already have anything plugged in to it).

6. Find the white wire (marked "T2"). [You should find it plugged into Terminal 3, which is located at the left side of the TOP ROW of the wiring block (this is above and just to the right of Terminal 1).]

7. Unplug the white (T2) wire from Terminal 3 and plug it onto the (now) open prong of Terminal 1 (where the brown P2 wire previously was located).

8. Replace the access plate on the motor and tighten the two screws that hold it in place.


1. Do NOT used the existing power cord (or, at least, not the existing plug on the end of it). This is a critically important safety point. (Apparently, some people use the existing cord/plug and wallow out the socket on the 220/230V outlet so the prongs of the plug will fit into it. Please don't try to do this -- You do not want the power cord configured such that it inadvertently could be plugged into a 110/120V outlet, and you do not want to have an outlet "carved up" so that a 110/120 device might inadvertently gets plugged into it.) If you're not going to get (or create) and install a new 220/230V power cord and want to just replace the plug on your existing power cord, be SURE the replacement plug is a 220/230V plug. Home Depot & Lowe's both sell replacement plugs for 220/230V use. Read the package carefully, though, as a 20A 110/120V plug looks almost like one variety of a 220/230V plug -- they each have one vertical and one horizontal flat prong, but the horizontal flat prong on the 220/230V plug is in the opposite side (R, facing end) of where it is on the 110/120V plug (L, facing end). They also have a 220/230V plug on which both flat prongs are horizontal. Whichever 220/230V plug you choose, make sure it matches the configuration of the 220/230V outlet you will be using.

2. If you do not have an existing 220/230V circuit AND want to install one, it's really not very difficult to do, IF you have some prior experience and are comfortable with installing/replacing/wiring breakers (If not, please hire an electrician!). Of course, the prime directive is you must be very careful working around an electrical panel.

2a. As far as the 220/230V outlet is concerned, if you've ever installed a 110/120V outlet, then installing a 220/230V outlet is essentially an identical process . . . up until you get to the point of connecting the wires to the electrical service in the panel. The 220/230V outlet will have 3 screws (like a grounded 110/120V outlet); the green screw is for the ground wire and gets the ground wire (bare copper or sometimes green insulated) from your 3-wire cable; a screw (usually gold color) on one side of the outlet gets the black "hot" wire from your cable; and a screw (usually silver-colored) on the opposite side of the outlet gets the white wire from your cable. The difference in 110/220V wiring and 220/230V wiring is that -- for 110/120V -- the white wire is not really "hot" and, instead, is a "common" wire that ultimately gets attached to the common or ground lug bar in the wiring panel, while -- for 220/230V -- the white wire in the cable is truly "hot" and ultimately gets attached to a circuit breaker in the wiring panel that is separate from the circuit breaker to which the black "hot" wire in the cable gets attached.

2b. Creating a 220/230V circuit in the panel requires using two separate breakers (these can be 15A or 20A breakers - I chose 20A breakers, so the wire in the cable to the outlet had to be at least 12 gauge; as I understand it, if your cable's wire is only 14ga, you're limited to using only 15A breakers). The 3-wire cable from the outlet gets connected in the panel as follows: Ground wire (bare copper or green) gets attached to the ground lug bar. Black ("hot") wire gets attached to one circuit breaker in the panel; and the White (other "hot") wire gets attached to a different circuit breaker in the panel. IMPORTANT NOTE -- these two breakers comprising this 220/230V circuit must not be on the same "side" in the panel: One of these breakers must be on the left side of the panel and the other breaker must be on the right side of the panel. By "side", I'm referring to the two vertical rows of breakers in your panel. If you attach the black and white wires to 2 breakers that are on the same side in the panel, you will not be creating 220/230V power and the 220/230V motor will not run.

More background info: Mine is a Sears Craftsman Compressor Model # 919.152940, but I learned during my research that it uses an OEM motor made for DeVilbiss by GE Motors, which must have been the supplier of these compressors to Sears, and probably others. So there could have been a number of various brands whose compressors were OEM'd by DeVilbiss and therefore are likely to have this same (or a later generation) motor.

My compressor's manual contains no specific instructions for accomplishing the conversion (so don't bother looking). Instead, there is only a reference that the customer needs to buy Sears' Conversion Kit # K-0191 (which supposedly contains the instructions along with a 220V cord and plug).

However, Sears no longer supplies this Kit and a call to the Sears parts people yielded no specific information about accomplishing the conversion, other than that at least some of these GE motors included a folded up instruction sheet inside the access plate (however, I now believe these "instructions" are just a copy the same diagram that is marked on the motor's label). SO LOOK INSIDE YOUR COMPRESSOR'S MOTOR'S ACCESS PLATE!

Mine didn't have the "instructions", so, I called GE Motors and learned that GE sold its small motor division (which made these air compressor motors) several years ago to Regal Beliot. When I called them, I learned that they were placed in Regal Beliot's Monarch division or subsidiary. From the Regal Beloit representative, I learned that this model GE motor was an OEM product made by GE for DeVilbiss, and that subsequent generations of these motors were made with slight variations in Model numbers (that's why I suspect the instructions above may be more broadly applicable than just to my, or even Sears', compressors ).

I hope some or all of this information is useful to others and I'm glad to have it recorded somewhere so I can get it all out of my head. <g>

Last edited by pdalton; 06-05-13 at 03:16 PM.
Old 06-06-13, 02:53 AM
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Welcome to the forums.

I see your first post is a novel. Thanks for the information.

Every motor is different when it comes to converting between voltages. Like you said..... be sure to check wiring plate or label for info.

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