microwave transformer and the ground.

[NR5P]

I've got a microwave transformer.  2300v on the secondary with 120 primary.  I think it is 1300 watts if I remember right.  I've heard that all the microwave transformers have one side of the secondary grounded.  It doesn't appear this way on this transformer.  The transformer doesn't appear to be connected to the secondary at all.  I guess maybe some didn't do this but I'm afraid that maybe there is a bad connection.  I want to be as safe as I can with this.  I'm using it for a single gi-7b amplifier.  It's about the right plate voltage for it. 

[K6IC]

All I know is what I've read ... while you wait for those knowledgeable,  have you seen this thread : ?

http://amfone.net/Amforum/index.php?topic=20293.0

EDIT:  AND,  another thread here had a link to to the Wiki :  (not particularly detailed, tho).

http://wiki.4hv.org/index.php/Microwave_oven_transformer

I,  too,  believe that one end of the secondary was connected to the frame of the trnasformer.  Hope that the sec is not open.

73  GL  Vic

[KE6DF]

I have only one Microwave transformer so my experience is limited.

Both leads of the secondary come out, but one of them comes out near the core and is only about 1/2 inch long and is attached to the core with a small screw.

That lead also has very thin insulation.

The other lead has normal insulation.

Now I could take out the small screw, solder a longer wire on the 1/2 inch lead, and then slip some spaghetti tubing over the connection.

Would this work? I don't know, but the insulation is very thin and I suspect there would be a risk of arc over.

Better to find two identical Microwave transformers, and use the two grounded sides as the center tap in a full wave rectifier circuit.

[NR5P]

I was just inspecting the transformer .  I was looking at the other sec windings I guess for the heater.  I noticed that one side is supposed to be connected to the chassis.  it was connected outside and came unsoldered.  am i in luck that the other side is connected where I can get to it? 

[NR5P]

oh and any tips for driving out these two shunts?  Also I'd like to say this is a great board.  I really like the attitude of amers and love listening to the AM window, the best conversations on ham radio go on there.

[Ed/KB1HYS]

Drive out the shunts with a tool of similar size and shape. A hammer and vice will be very helpful. 
When you drive the shunts out, you may have to put some non-magnetic material back in (hardwood block) if the things HUM from the windings vibrating.  Or you can wind in a low voltage winding if you need another voltage off the secondary. (a bit of work but it's an option).

Isolation between the secondary and frame is poor. The frame is meant to be attached to the 'cold' end of the secondary.  If you use it with the frame floating, mount it on isolation feet, a board, or a polyethylene cutting board.   

Make sure the windings really are copper and not aluminum.  The aluminum wire seems to break if bent around a bit, and is impossible to solder to with normal solder & flux.

I've used 3 of these so far build my HB power supply.  One I cut the secondary out of one and wound in my own for my 866 rectifiers filaments, other filaments, and other low voltages I needed.  The other two are back to back in the usual center tapped configuration. 

Cheaper than plate iron(free usually) but have limitations and require work to use.

[NR5P]

I'm going to use an isolated standoff lug and solder the "supposed to be grounded" part of the secondary to it since the transformer winding is ofcourse flimsy.  Luckily it is copper so that is one problem I don't have.