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Eaton Control Transformer

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This is a brand new transformer I had a starter given to me and 5the transformer in there didn't have the right primary voltage. the new 1 is 208 primary and 24 volt secondary. When the primary is connected and voltage checked on the secondary it is 28 to 33 volts which is fine without a load on it. when I connect it straight to the starter coil it doesn't do anything abd it shows zero volts across the terminals. Anybody with answer for this
 

tom baker

First Chief Moderator & NEC Expert
Staff member
Location
Bremerton, Washington
Occupation
Master Electrician
What is the supply voltage to the xfmr?
What is the coil voltage?
And what is the resistance of the coil, or do you have a spare coil to compare it to?
 

hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
What is the VA rating of the transformer? Can you post the wiring diagram on the front of it? This is not a doorbell style transformer? If it is, it is probably current limiting, and the starter coil is way over it’s rating, and that’s why it goes to zero.
 

synchro

Senior Member
Location
Chicago, IL
Occupation
EE
I suggest putting a clamp meter around one of the wires feeding the coil to see how much current it's drawing.
What is the actual voltage reading that you're measuring across the coil? If it's actually reading zero volts then you must have a dead short and/or no current flowing.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Time for a little process-of-elimination troubleshooting. I would first see if the transformer will supply a small 24v load.

If you temporarily isolate the contactor from the other wiring, you could even use the contactor coil itself as a test load.
 

tom baker

First Chief Moderator & NEC Expert
Staff member
Location
Bremerton, Washington
Occupation
Master Electrician
Just a comment, we get a lot of interesting posts, give answers, and never hear back. I think the OP is initially reaching out to get it working or done, and then just doesn't have time to come back with followup
 

hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
I have a feeling they were trying to use a power limited transformer such as a doorbell transformer, and it doesn’t have enough va to pull in, but being power limited, it goes to zero. A lot of people have the mistaken thought that because it’s 24 volts, it doesn’t take much power. Just a guess.
 
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