| pkjames |
Dear fellow diyers,
I recently acquired a pair of vintage transformer and wanted to use them in my new tube amp project. Just realized that in the input section it states : 1 & 2 PRI 115V 1600~
Does this mean it was from an old high freq. equipment and runs @ 1600HZ or it means something that I don't need to worry about?
Or if there is someway I could test if they runs @ 50-60HZ? I am thinking just plug them into 110v supply and see if it gives me 6.3v output, but if it does runs @ 1600hz, would I burn it?
Regards,
James
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| tubelab.com |
I have not seen a 1600Hz transformer in the US, although 400Hz transformers are common in airborne and shipboard equipment to save weight. A transformer for a higher frequency does not need as much inductance as a 50 - 60 Hz transformer, so far less iron is needed, thus allowing a considerable weight savings. If you were to operate such a transformer on 50 - 60 Hz the lack of primary inductance would cause a large current draw even with no load. This leads to a short unhappy life for the transformer.
If the transformer is considerably smaller and lighter than a 50 - 60 Hz transformer of comparable power ratings, don't even try it. It will fry. If the transformer is about the right size, connect an incandescent light bulb of 50 to 100 watts in series with the primary and apply power with no secondary load. If the bulb lights up brightly, the transformer is bad or unsuitable for the power source. If there is a dim, or no glow, then measure the secondary voltage. If it is OK, then the transformer may be usable.
I use this method to test all unknown, vintage or utherwise questionable transformers. It cuts down on the amount of smoke I generate! This assumes that the transformer, the power source, and the light bulb are all rated for the same operating voltage. That may not be the case in your location.
Operating two 115 volt transformers in series off of a 230 volt line (mains) is not recommended unless the transformers are identical and will see the same load current under ALL operating conditions. |
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| Tom Bavis |
If it is designed for 1600 Hz, it won't work at 115V / 50-60 Hz. The core will saturate before you get to 10V on the primary, let alone 115...
How big and heavy are these? That's a clue - a 200 VA 60 Hz transformer will weigh about 7 pounds - 3 kilos - and will weigh a little more if rated for 50 Hz. |
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| opcom |
| they look like military type units. Maybe ran on an inverter. |
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| pkjames |
these are pretty light units, considerabley smaller than other units I have. I guess they are higher freq. units. Still, I will just probaby hook up a fues in series with the primary to test out. I guess if it blows up then it must be bad.
Thanks for the input,
Regards,
James |
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| Miles Prower |
Looks like old military wierdness. If you have a variac, then try 'em out at about 4.0V at 60Hz, and bring up the voltage slowly. If these are 1600Hz units, they'll saturate pretty quickly, and you won't be able to use 'em at 60Hz.
If it is a 1600Hz model, the core will be way too small for 60Hz. |
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| opcom |
An easy way to test is to apply one of the correct voltages at 1600Hz to it using an audio amp. Then you can, while keeping the exciting voltage constant, monitor the current (magnetizing current) as you reduce frequency. When it increases by about 10%, that is probably the lowest frequency for safe continuous use. It is possible they would take a square wave as well.
Maybe better face it they are for a specific use not assocated with 60Hz! Might make decent small modulation transformers for low power tube type ham radio where fidelity is not as important to some. If you don't want them, send them here!! (shipping might exceed the value!!) |
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