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Transformer spec parameter - what is working voltage?

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AlienCircuits

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Is this the voltage that can exist across a single winding of the transformer, where it would be dependent on the lacquer or winding insulation? This is different than isolation voltage between primary and secondary windings.
 

brushhead

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A transformer will be designed to operate at an AC voltage and Frequency. This has a direct influence on the magnetic parameters in the transformer core. If you start to drop your frequency, or raise your voltage you can 'saturate' the core whereby it is operating past a safe level and then all bets are off.

For a sine wave V = 4.4*B*A*N*F

Where:

V is operating voltage RMS
B is core flux density
A is area of core in m^2
N is number of turns
F is frequency

That's from memory and I think it's right. Anyone else, please jump in.

Rob.
 

AlienCircuits

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A transformer will be designed to operate at an AC voltage and Frequency. This has a direct influence on the magnetic parameters in the transformer core. If you start to drop your frequency, or raise your voltage you can 'saturate' the core whereby it is operating past a safe level and then all bets are off.

For a sine wave V = 4.4*B*A*N*F

Where:

V is operating voltage RMS
B is core flux density
A is area of core in m^2
N is number of turns
F is frequency

That's from memory and I think it's right. Anyone else, please jump in.

Rob.

The transformer I'm asking about has a 150 VDC working voltage, and so it is rated at 0 frequency. I should have specified the working voltage was DC, and maybe that changes my question for you?
 

schmitt trigger

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I agree with brushead.

Either it is not a transformer or the specification is incorrect or incomplete.

Would you kindly share the web link, file, or paper document where the specification is actually written?
 

AlienCircuits

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FvM

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In this case, 150 VDC is actually the insulation working voltage, the voltage that's expected to be applied permanently, in constrast to the isolation voltage which is only tested for 1 minute. You find resepctive specifications in safety standards like IEC1010.

The "working voltage" of a mains transformer would usually specify the rated primary voltage.
 

schmitt trigger

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It is a small world. I actually worked for Triad in 1991.

At the time, we also built a "Blue Spec" line, which was sold to the US Navy.

But to FvM's point: many people misunderstand the whitstanding (or isolation) voltage with long term working voltage.
Higher voltages cause breakdown due to corona effects and other, and are only short term applications. As FvM mentions, they are rated for a short period, as established by regulatory and safety Agencies like IEC or UL.
 

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