Latest Discussions : Electrical & Lighting


09:51AM | 09/06/07
Member Since: 09/05/07
2 lifetime posts
Got a very old Sears 2cyl(V) compressor at a garage sale. I have run it in my garage for 4hr+/- with no issues on 115v wall plug.

Now, took it to job site and 4000 wat generator will only run it up to pressure once and then no restart with pressure in tank.

So, want to wire it for 230v. Diagram on motor mostly rubbed away. Currently all that is visible on diagram shows for 115v to have:

Yel on term. 2

Blk on term. 2

Red on term. 4

Yel on term. 4

Took the cover off of motor and found:

yel on term. 1

blk on term. 2

red on term. 4

yel on term. 4

Thought maybe it was already wired for 230, swapped the plug for a 230v version and tried it on generator. Nothing.

Don't really care why it was wired the way it was, just want help in connecting it properly for 230v.

Don't really know much about the rig. Name plate used to show how to wire for 230 but mostly rubbed off and illegible. The unit is brown all over. Motor appears to be about 2hp.

It is not a "capacitor" start type. Motor model # CM240K6. 1750rpm. FLA unknown.

Any help is greatly appreciated.


Tom O

02:55PM | 09/06/07
Member Since: 09/17/02
476 lifetime posts
I really can't give you any advice about rewiring to 240 volts, but it may not be necessary.

Generally speaking, the pressure switch should bleed off any head pressure. Compressor motors trying to start against this pressure have a really tough time of it and it sounds like this is the root cause of your problems.

Also, your 4000 watt generator does not deliver 4000 watts to the receptacle that you're plugged into, 2000 watts would be more likey. Between the high current demand of starting the motor and any possible high head pressure issues, that could easily account for the no start condition.


03:03PM | 09/06/07
Member Since: 09/05/07
2 lifetime posts
No doubt you are right as the bleed is not even connected. Didn't worry about it as it ran ok in garage.

Still would like to run it on 230V though. If not successful, I guess I'll hook up the bleed off.


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