magnetic shunt in uWave oven xformer

[Ray di Tutto]

Hi

I recently took apart an old microwave oven and I found there were two
square pieces of metal between the power transformer core and the windings.
Someone told me it was a magnetic shunt but was unable to tell me what
their use was. I am planning to re-use this transformer for an RF radio
amateur power amplifier. Should I try to take the magnetic shunts away?

I wonder why the oven manufacturer put them there in the first place.

Many thanks

Angel Vilaseca HB9SLV

 

[mike]

Ray di Tutto wrote:

Hi

I recently took apart an old microwave oven and I found there were two
square pieces of metal between the power transformer core and the windings.
Someone told me it was a magnetic shunt but was unable to tell me what
their use was. I am planning to re-use this transformer for an RF radio
amateur power amplifier. Should I try to take the magnetic shunts away?

I wonder why the oven manufacturer put them there in the first place.

Many thanks

Angel Vilaseca HB9SLV

Magnetic shunts increase the output impedance.
If you take 'em out, the coupling goes up and the output impedance goes
down, but it still may be too high for your application. Primary
inductance goes down.
Another thing to worry about is the duty cycle. Microwave ovens don't
run for long periods. Even unloaded, there may be enough loss in the
transformer to heat it up. Core may saturate, etc.
mike

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[Sam Goldwasser]

Ray di Tutto <ray@o-matic.com> writes:

Hi

I recently took apart an old microwave oven and I found there were two
square pieces of metal between the power transformer core and the windings.
Someone told me it was a magnetic shunt but was unable to tell me what
their use was. I am planning to re-use this transformer for an RF radio
amateur power amplifier. Should I try to take the magnetic shunts away?

I wonder why the oven manufacturer put them there in the first place.

A magnetic shunt is normally in a transformer to provide current limiting.

For other applications, it should be removed.

WARNING: EXTREMELY LETHAL with shunt. Even more lethal without the shunt!!!

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