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On 2/6/17 2:27 PM, Ronald Reeland wrote:
Hi:
I have a MOT from an old GE oven. One side of the high voltage output is connected to the transformer laminated metal plates or frame. I am guessing that was for some sort of safety reason. Can anyone explain why it is connected to the frame? And if for safety, how exactly that is achieved?
More about saving money, in addition to safety. A microwave oven
operates the tube from a half wave doubler. The anode of the tube is
grounded, and the cathode is at roughly twice the voltage of the
transformer (negative), around 2500-3000V. The filament winding floats
at the negative cathode voltage.
Since the anode is grounded, one winding of the transformer is grounded.
You want the core of the transformer grounded, in case there's a short
from the HV winding.
This saves money, because the inner layers on the transformer (closer to
the core) can have less insulation, since they're at a lower voltage
than the HV end of the winding.
Lastly, is there any harm in disconnecting the wire from the frame? Planning for a vacuum tube tesla coil application.
Well, you need to be aware that the insulation might not be as good from
the "cold" end of the winding. That said, folks have run 4 transformers
in series under oil.. two with the conventional grounded end, and the
next two in series, with the cold end connected to the hot end of the
lower stage.