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Old 03-02-2017, 02:58 PM   #1
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Default Control transformer

Hey all. My customer purchased a Timesaver model 50-19m. Its set up for 208 but he wants to run it at 480. There are two, 9 lead motors which I rewired for 480. The mag coils are 120. I cannot figure out the control transformer. The secondary side has 2 whites and 2 blues. Easy enough, that's two 120v coils. The primary side has 6 leads, no diagram and no identification of any kind on the wires or transformer itself. Anyone run into this before??
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Old 03-02-2017, 03:40 PM   #2
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Pump it with some low voltage AC ... from another control transformer.

Have all of the leads anchored into mechanical lugs -- which are screwed into a dry plank of wood. You don't want them flopping around.

Now you can take your readings, as a transformer is a transformer, using a DMM.

You won't let the smoke out, either.
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Old 03-02-2017, 04:11 PM   #3
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I heard from the manufacturer. Here is the diagram, never seen a transformer like this. Are these common??
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Old 03-02-2017, 04:19 PM   #4
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Quote:
Originally Posted by TRurak View Post
I heard from the manufacturer. Here is the diagram, never seen a transformer like this. Are these common??
It looks like it's engineered for the world market.

Multi taps for low voltage and conventional control power, both.

This project is just another example of why you don't want customers blindly purchasing elements for you to field engineer. ( for free, too, in practical terms )
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Old 03-02-2017, 04:37 PM   #5
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This isn't an aftermarket part. The strange part about it besides the 6 lead primary is the dual voltage of the 2 secondary coils. 120 on one coil and 10 on the other. Normally you have two 120 coils which you could series for 240 correct?
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Old 03-02-2017, 05:24 PM   #6
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Originally Posted by TRurak View Post
This isn't an aftermarket part. The strange part about it besides the 6 lead primary is the dual voltage of the 2 secondary coils. 120 on one coil and 10 on the other. Normally you have two 120 coils which you could series for 240 correct?
It would be odd... as their is no demand for 240 VAC control power.

For all kinds of reasons, control circuits are either low voltage (24 VAC) or L-N. ( 120 VAC )

Such transformers are commonly purchased as an OEM item. (ie from an outside source that really cranks them out in volume. This relationship is usually obscured.)
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Old 03-02-2017, 09:07 PM   #7
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Transformers similar to this are common on older machine tools. They have a sort of universal line side and two, three, or four different voltage outputs on the secondary for different uses on the same machine. Some secondary combinations that I have seen: 200, 110, 24; 110, 48, 24; 60, 24; 110, 48, 40, 20; and 48, 24, 10.

When they go bad, be prepared to improvise.
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Old 03-02-2017, 09:40 PM   #8
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As mentioned in previous reply....feed secondary side with 24 vac and measure the output from the various primary leads....white should be common on the primary. Then you ll know the ratios.
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Old 03-02-2017, 10:42 PM   #9
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As mentioned in previous reply....feed secondary side with 24 vac and measure the output from the various primary leads....white should be common on the primary. Then you ll know the ratios.
don't you mean 10 or 120?there really is no 24 volt side, at least what i'm seeing. any way feed the two white's with 120.then check the primary. it will give you ball parks . but proably not exact, because it's not loaded.
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Old 03-02-2017, 11:28 PM   #10
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I got to be an old electrician by being careful about electrical equipment ...and learning from the mistake of a few co-workers who didn't go home to their families afterwards .
If I'm checking "unknown" control transformers I like to use a extra low safe voltage ...it's all about ratios anyway....you know 120 to 24 =5:1 ratio . So the primary winding is going to be a ratio of the secondary ...so just incase there's a 600 normally...you'll get 120 instead with the 24.
Or you can use an ohmmeter and get the ratios ....very safely !
As an aside ...that's why if some homeowner "hots up" his panel with 230/120 during a power outage it'll bump back to the power company transformer ; if he doesn't isolate the main breaker....and hot up their primary ....maybe back to 14.4Kv....even for an instant ....some lineman might end up dead !
You only get points for having toys....not for being dead .
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Old 03-03-2017, 06:51 AM   #11
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Thank you all for the advice. I've done some minor machine control work but not enough to be confident. It amazes me that there is always something new to learn in this trade.
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