# single phase motor controlled by drum switch



## mbednarik (Oct 10, 2011)

I hooked up a single phase baldor motor yesterday and it last for about 30 seconds. The wiring diagram on the motor wanted 3-2-5 connected, 1-8 connected to line, and 4 connected to the other other. Typical switch 5 and 8 for forward and reverse. With this drum switch setup i can only break one side and i have to leave the other line connected. With the drum switch in one position it connects line to 1 & 8, and connects 2-3-5. Runs fine drawing nameplate at 4.4A. switch the drum switch to the other position it connects line to 1 & 5, and connects 2-3-8. So the motor has power from the other leg connected all of the time. I can't think of a reason why it would hurt the motor but with the motor burning up that quick it just has me questioning myself.


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## wildleg (Apr 12, 2009)

http://attachments.temcoindustrialpower.com/product_info/Baldor-L3408.pdf ?


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## micromind (Aug 11, 2007)

I would suspect the motor.

Baldor used to be pretty much top of the line, but in the last year or so, I've had quite a few that didn't last very long, and weren't being abused. 

They were replaced with USEM or Leeson, and those motors still run fine.


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## John Valdes (May 17, 2007)

wildleg said:


> http://attachments.temcoindustrialpower.com/product_info/Baldor-L3408.pdf ?


Reversing leads 5 & 8 on this motor will not reverse it. That motor in your link is not reversible according to the connection diagram.

OP. Find the model number on the motor and go to the Baldor web site.
Find the motor you have and look at the correct connection drawing. 
If the drawing does not state it can be reversed it cannot be reversed.
But you are right, 5 & 8 are the number most always, interchanged for reverse rotation.

Note: Baldor ALWAYS shows/tells the reverse capability on each cad drawing if it is reversible.


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## micromind (Aug 11, 2007)

John Valdes said:


> Reversing leads 5 & 8 on this motor will not reverse it. That motor in your link is not reversible according to the connection diagram.
> 
> OP. Find the model number on the motor and go to the Baldor web site.
> Find the motor you have and look at the correct connection drawing.
> ...


I'm pretty sure the motor listed in the link is reversible. 

Looking at the connection diagram (page 9 of 9), it lists high std., high opp, low std., and low opp.

This would be high voltage (230) standard rotation, high voltage opposite rotation, and the same for low voltage.

It's a basic 6 lead dual voltage single phase motor with no thermal protection. 

Also, on page 2 of 9, it lists rotation as R. This means reversible.


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## wildleg (Apr 12, 2009)

fwiw, the drawing in the link shows 1 to line, and 4 swapped out with the 5/8, whereas you are using 4 as line, and 1 swapping out. don't think it makes any difference but not sure.


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## wendon (Sep 27, 2010)

mbednarik said:


> I hooked up a single phase baldor motor yesterday and it last for about 30 seconds. The wiring diagram on the motor wanted 3-2-5 connected, 1-8 connected to line, and 4 connected to the other other. Typical switch 5 and 8 for forward and reverse. With this drum switch setup i can only break one side and i have to leave the other line connected. With the drum switch in one position it connects line to 1 & 8, and connects 2-3-5. Runs fine drawing nameplate at 4.4A. switch the drum switch to the other position it connects line to 1 & 5, and connects 2-3-8. So the motor has power from the other leg connected all of the time. I can't think of a reason why it would hurt the motor but with the motor burning up that quick it just has me questioning myself.


 I presume it's wired 240?


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## wendon (Sep 27, 2010)

wildleg said:


> http://attachments.temcoindustrialpower.com/product_info/Baldor-L3408.pdf ?


If that's the diagram, it appears there's no thermal protector. Why wouldn't something like this work? It's kind of a crude diagram!!


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## micromind (Aug 11, 2007)

wendon said:


> If that's the diagram, it appears there's no thermal protector. Why wouldn't something like this work? It's kind of a crude diagram!!


If it's a 6 lead 1ø dual voltage motor, there is no thermal protector. If it has 7 leads and two of them are P1 and P2, then there is an O/L built in to it.

The diagram shown is pretty much standard for 1ø dual voltage motors. 

If you study it a bit, you'll find that all 3 windings are in parallel for low voltage, and swapping 5 and 8 will reverse the rotation. 

For high voltage, the two run windings (A Phase in this case) are in series and the start winding (B Phase in this case) is in parallel with the 3-4 winding.

P.S. The diagram you posted will work as intended.


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## wendon (Sep 27, 2010)

Or you could possibly do this and only need three wires and a grounding 
conductor.


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## John Valdes (May 17, 2007)

Are you guys looking at the same drawing I am? (CD0001). 
How would reversing 5 & 8 in drawing CD0001 do anything? Also, Baldor always indicates on their drawings the reverse interchange connection. This drawing does not show one or mention one. 
Like I asked. Are we looking at the right/same drawing? Thanks


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## micromind (Aug 11, 2007)

The drawing I'm looking at is CD0001. It is for a Baldor L3408 1/2HP two pole dual voltage 1ø 6 lead motor with an optional thermostat for thermal protection.

It's obvious to me that on page 9 of 9 the two windings labeled A Phase are both 115 volt main windings, and the winding labeled B Phase is a 115 volt start winding.

As usual, the start winding is in parallel with the 3-4 main winding when connected for 230 volts. Changing the phase relationship of 3-5 and 4-8 will cause it to start in the other direction.

P.S. The reverse interchange is listed on the connection table as STD (standard rotation) and OPP (opposite rotation). The only difference between STD and OPP at each voltage is that 5 & 8 are swapped.


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