V.us rating of pulse transformers is ambiguous?

[opampsmoker]

Please assist with V.us rating of pulse transformers?

The PA2002NL pulse transformer datasheet states that the V.us rating is for unipolar pulses. It states that when bipolar pulsing is being done, then the V.us rating is actually double the stated V.us rating. This makes good sense.

However, the Murata 78602/16C pulse transformer datasheet makes no statement about whether the V.us rating is for unipolar or bipolar pulsing……….Do you know which it is?

PA2002NL pulse transformer datasheet:
**broken link removed**

Murata 78602/16C pulse transformer datasheet

http://www.murata-ps.com/datasheet?/data/magnetics/kmp_786.pdf

 

[KlausST]

Hi,

for a single unipolar pulse the magnetic field goes from zero to max_gauss. Then it needs enough time to go back to zero.

but for a symmetric bipolar pulse it goes from -max_gauss to +max_gauss. Thus you have twice the time...

Klaus

 

[opampsmoker]

Thankyou , yes i agree with you. For the Murata transformer, are they referring to unipolar or bipolar pulsing with the V.us rating stated?

 

[KlausST]

Hi,

I´d say "single pulse" --> unipolar
But I´m not sure. Didn´t read the datasheet ... but I remember I have used similar ones.

Klaus

 

[mtwieg]

I've actually never seen a v*t product specified as unipolar or bipolar. When I see a v*t product I always assume it's for a single unipolar pulse, meaning it takes the core flux density from 0 to Bmax.

 

[Easy peasy]

that is a bit of an assumption - magnetics companies are famous for "specmanship"

easy to email and ask them though ...

 

[opampsmoker]

wey hey...
official answer from Murata....

The Et rating of our transformers is tested with a single pulse starting with a completely demagnetised core.
As with all pulse transformers, high pulse repetition frequencies may cause a build-up of remanence and could lead to saturation of the transformer. If this is the case, measures should be taken to sufficiently demagnetise the core through 1) bipolar operation, 2) reduced prf (increased ‘off’ period), 3) use of a Zener diode in series with a flywheel diode on the primary winding.