[Collins] You Won't Believe This

[Dr.Gerald Johnson]

Yes it could be static drag from the pointer with 4 KV attached. The meter 
movement is surely connected to one of the terminals because meters 
generally don't have room for that much high voltage insulation between 
the coil and the magnet and other pieces of the works.

Are you SURE it should be connected in the positive lead. Being behind 
glass it ought to be mounted on an insulating panel. Its not like Collins to 
stress a meter that way, most metering circuits I've been around were 
arranged to have the meter close to ground. A few plate voltage meters 
had the multipliers outside at high voltage where high humidity tended to 
make them read high and to blow movements but a couple diodes cured 
the loss of the meters in the 821A-1.

I'd want to put that meter in the negative lead, probably shunted with a 1 
or 2 ohm resistor so surges wouldn't blow the meter open.

I suppose one might mount a circle of wire around the barrel of the meter 
connected to one of the terminals to spread the electrostatic field and 
hide the meter pointer from ground.

73, Jerry, K0CQ, Technical Advisor to the CRA

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Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
Reproduction by permission only.