Transformer from overseas

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Ponchik

Ponchik

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Location
CA
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Electronologist
I have a medical equipment that was purchased from Middle East and it came with a separate transformer that is not part of the equipment but it was used with the equipment to step down the line voltage to 200V. The transformer does not have any information on it. It does have primary taps with voltage marking and one of them is 480V.

My question, the voltage rating of the equipment is 200V at 50HZ. Can the supplied transformer work with our voltages such as 480 V?

Or I am better off to get a new transformer that is designed for our voltages and is rated at 60HZ?
 
The transformer will operate at whatever frequency it is supplied.

The bigger concern is whether the equipment will run on 60 Hz.
 
LarryFine said:
The transformer will operate at whatever frequency it is supplied.

The bigger concern is whether the equipment will run on 60 Hz.
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Because of the 60Hz, manufacturer suggested that I supply the equipment with 208V instead of 200V.

So any transformer will operate at 50 or 60 Hz? Am I understanding you correctly?
 
edward said:
I have a medical equipment that was purchased from Middle East and it came with a separate transformer that is not part of the equipment but it was used with the equipment to step down the line voltage to 200V. The transformer does not have any information on it. It does have primary taps with voltage marking and one of them is 480V.
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Is there a tap on the primary for about 462V (i.e., 4% less than 480V) ? That would be necessary to get a 208V output from the transformer when driven with 480V.
 
In the other direction, a transformer designed for 60 Hz may or may not work properly on 50 Hz. The increased magnetizing current into the transformer inductance at the lower voltage may cause the core to saturate if it was not designed with sufficient reserve. One way to avoid saturation would be to reduce the primary voltage by a factor of 5/6 from the nominal, keeping the volt/Hz ratio the same.
 
I agree with HHSINSP.

I am guessing this is for a place where OSHA applies. OSHA requires that all electrical devices be listed or labeled by an OSHA-approved NRTL (nationally recognized testing laboratory).

There is no way I would install an unmarked power transformer in a medical application.

Is the piece of medical equipment itself so listed or labeled? If not, there is no way I would want to take on the liability for this.

I don't know where in California you live or what the legal requirements are there, but you may need a licenced electrician do do this install and an electrical permit and inspections. If I were the electrical inspector there is no way I would approve using non-listed equipment in a medical setting.
 
HHSINSP said:
Is the transformer even listed?
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is the equipment it is supposed to supply listed?

does article 450 actually require transformers to be listed?

realistically, the level of liability a contractor takes on for installing unlisted equipment is no greater than if it is listed. if it fails in some way that kills someone, everyone that was involved in the installation will be sued, regardless of listing or not. that is why you have liability insurance.
 
200V 50Hz? isn't that a standard supply voltage in Japan?

Japan is a little unique since 50Hz is common in the east of the Country & 60Hz in the West, but both 100V & 200V are standard voltages there.
 
GoldDigger said:
In the other direction, a transformer designed for 60 Hz may or may not work properly on 50 Hz. The increased magnetizing current into the transformer inductance at the lower voltage may cause the core to saturate if it was not designed with sufficient reserve. One way to avoid saturation would be to reduce the primary voltage by a factor of 5/6 from the nominal, keeping the volt/Hz ratio the same.
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This is what I've always been told.
 
petersonra said:
is the equipment it is supposed to supply listed?

does article 450 actually require transformers to be listed?

realistically, the level of liability a contractor takes on for installing unlisted equipment is no greater than if it is listed. if it fails in some way that kills someone, everyone that was involved in the installation will be sued, regardless of listing or not. that is why you have liability insurance.
Click to expand...
I don't know if the equipment has any testing laboratory tags on it. I know that transformer that came with it has NOTHING on it. Just the voltage markings on the primary and secondary.
 
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