Re: Re: LF: Microwave oven transformers

["Alan Melia" <alan.melia@btinternet.com>]

 Hi all, I am very please to see not everyone sticks to a 12 volt maximum
supply voltage
:-))

One though that occurs to me is that if one side of the MO transformer is
grounded in oven service........one ought to check that the winding as a
whole is sufficiently well insulated from ground to stand floating 2kV above
ground. There may not be the same clearance /insulation on the grounded end
of the secondary as the intended high-voltage end?? On the other hand it
might be quite OK. I have a certain cynicism about "consumer designs".

Alan G3NYK


----- Original Message -----
From: <dl4yhf@freenet.de>
To: <rsgb_lf_group@blacksheep.org>
Sent: Wednesday, July 15, 2009 2:34 PM
Subject: Re: Re: LF: Microwave oven transformers


These special transformers need the magnetic bypass because a magnetron
looks (as a load) like a Z diode.
So they are powered, more or less, with a constant current source rather
than a constant voltage source.

In other words, the "generator" (transformer) must have a large source
impedance, and that's what the magnetic bypass in the 'former does.

Cheers,
  Wolf .