I need to change a 240/120 motor from its current 240 configuration to 120 volts. The instruction plate for making this change is long gone. The motor voltage switching method is not the standard/general set-up.

The present 240 wiring is:

1) L2 is connected to T4.
2) T3 is connected to T2.
3) T1 is permanently connected to T5 (soldered) and both are connected to the back of the reset button.
4) L1 is connected to P1, which is connected to the reset button.
5) P2 from the reset button is not hooked up at all.

The biggest part of this puzzle that has me confused is that T1 and T5 are together. Does this mean that the motor cannot be switched to 120v (only reversed)? If anyone can help, I'd really appreciate it. Thanks

This may help you. However if you know the motor manufacture you could possible get the information off the internet or by phone to be sure.
http://www.elevatorconcepts.com/PDF_Bulletins/PPDFSB013.pdf

The schematics on that site don't match my situation. I'm not sure I can get any info from the motor manufacturer. There is virtually no information left on this old motor so it would be very hard to let the representative know which model we were dealing with. Thanks for the response though.

From your current connection description, it appears that "T2" and "T3" will be the ends of the Split Run Windings. Notice that "T2" and "T3" are jumpered together - such as in a Series Connected fashion.

"T4" would be the end of the 2nd Split Run Winding (this Coil having ends labeled "T3" and "T4").

"T1" would be the end of the 1st Split Run Winding (ends labeled as "T1" and "T2").

"T5" looks to be the Aux. / Start Winding's end.

If all this is correct, then changing the Configuration from Series (High Line Voltage, or 240 VAC) to Parallel (Low Line Voltage, or 120 VAC) would be done via "T2" and "T3", as described below:

<OL TYPE=1>

[*] Remove the Jumper between "T2" and "T3",

[*] Connect a suitable sized Jumper between "T1" and "T3",

[*] Connect a suitable sized Jumper between "T2" and "T4".
</OL>

All other connections remain the same.

If you want to check the continuity of windings to find out which is which, that may be very helpful for connection determinations (now and in the future). You would be looking to find ends of each coil, and which coil is the Aux. / Start Winding (it will be in series with the Start Switch, and - if used, the Start Capacitor).

Again, this is just an observation, so maybe additional info from others should be taken into consideration first (if anyone sees problems with my posted data, please chime in).

Good luck.

Scott35

P.S. Don't know what to say about the "P2" connection from the Reset Button!
Also, are you sure it's a 120/240 VAC Motor? Is this indicated (in whatever "remaining" text) on the Nameplate?

S.E.T.

No, I am not sure that this is a 240/120 motor. There is just enough information left on the casing to make me dangerous! With T1 and T5 together at all times, I am starting to think that this is a 240 volt only motor that can be reversed. It is on an old, portable air compressor though so I don't know why an easily reversible motor would have been utilized. It appears to be the original motor since all components of the compressor seem to be factory painted the same color. Why would a company pick an easily reversible motor for this duty? I don't understand ... my head is starting to hurt.

I should have mentioned a little more in that last reply!
<homersimpson>DOHH!!!</homersimpson>

This Motor appears to allow for 120 VAC or 240 VAC input - due to the (possible) Split Windings.

It also appears to be (meant) for only one direction of rotation, being that it's used for a Compressor's Pump, and the "T1" + "T5" leads are soldered together.
Reversing the Motor's rotation would be done with "T5" and "T6".

Hope this helps!

Scott35

Thanks Scott35, I'll be checking this motor out again this weekend and see if I can make sense of things.

triple;

Contact me directly via E-Mail. I may have some drawings that will help out with the Motor's connections.

Click on the "E-Mail Icon" above this message, and send mail as usual.

Scott35

p.s. If you prefer, I can post them on-line.

S.E.T.

I don't know if it is much help but....

I was taught that P terminals are named after 'pyro' in Greek, meaning heat or fire. They should be your 'normally closed' internal temperature shut down. P1 and P2 should be closed, when the motor gets hot they should open. They should be in series with either L1 or L2. I think T5 should connect to P2. It was probably changed because the thermal reset was burnt out.

[This message has been edited by Pinemarten (edited 09-23-2003).]

Eureka!

I got it figured out. You were right Scott35. I took your advise and ohmed everything out to be sure. The only deviation I made from your instructions was to hook T3 to P2 rather than directly to T1. T1 is connected to P2 through a normally closed contact of the reset button. I figured that P2 must have been there for a reason and it wasn't being used in the 240-volt configuration. Also, the supplied terminations did not allow a direct connection of T1 and T3. Therefore, an indirect connection seemed to be the next most probable scenario. Thanks allot for your help Scott35.

BTW, can you elaborate more on what type of changes would need to be made in order to reverse the rotation of a motor? I don't have to do it for the current situation, of course, but it may come up in the future.