Marv,
Did you check to see if one of the windings was connected to the core, and if
the core had a shunt in it? That is what most have that I've seen. Another
thing that really ticks me about their manufacture, and a few other
transformers too, is they weld the lams together. They put a weld right down
one side of the lams, front to back, one bead about 1/4" wide. That makes them
a bit*h to use for a rewind. A person with a mill, or be good with a disc
grinder can remove the weld. Also, the shunt needs to be driven out with a
hammer. This is really good though as it gives you more vertical window area
for a new coil. What gets me though is why weld them and still use screws to
hold the lams together?
Best,
Will
*********** REPLY SEPARATOR ***********
On 3/12/06 at 11:57 PM wc6w@juno.com wrote:
>QST
> Yesterday, I acquired a 2004 vintage Sharp microwave oven, from the
>"alley exchange", which was light (weightwise) enough that I thought it
>might contain a switching power supply.
>
> Upon examining the unit, I found that the incredible lightness was due
>to its construction with frame metal of soda can thickness, and that it
>contained a conventional transformer manufactured by one Digital Power
>Communications Co, Ltd.
>
> There was an article in QEX about 10 years ago that discussed the use of
>these microwave oven transformers in plate power supplies. It advised
>against using them in a conventional full wave bridge but, rather used
>them in an unorthodox half wave connection.
>
> Examining the transformer at hand, it appeared that the insulation was
>uniform over the full length of the secondary.
>
> I disconnected the "low side" secondary lead from the frame and
>hi-potted the secondary (also the primary just for science...) up to 4KV,
>referenced to the frame, with zero leakage.
>
> This suggests that one of these transformers might be employed in a
>"normal" connection for a low voltage (2500V) KW input amplifier. Or a
>pair of identical units in parallel for a 2KW input amp.
>
> Caution, this suggestion MAY NOT hold true for other makers of this
>style of transformer.
>
>73 & Good afternoon,
> Marv WC6W
>
>
>P.S. -- The magnets from the magnetron assembly make great refrigerator
>magnets!
>
>
>
>
>
>*
>
>
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