w8khk
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This ham got his ticket the old fashioned way.
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« Reply #1 on: December 01, 2021, 09:21:25 PM » |
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I think you have a good plan, Pat. If it still trips the GFCI device, there is another way to resolve the issue.
Place one capacitor from neutral (white) to ground (green). Place the other capacitor from hot (black) to neutral (white). This method should still provide good RFI suppression, but should NOT trip the GFCI device.
The GFCI is measuring the current on the neutral and the hot leads, and trips when there is a difference between the two. It does this by passing both the neutral and the hot (1 turn) through a toroid, and measures for a difference on the sense winding.
The original capacitor from hot to ground may cause enough imbalance to cause the device to trip, but the capacitor from neutral to ground should not cause a measurable current on the neutral lead, since both neutral and ground are very close to the same potential.
I normally use disc ceramic capacitors for the power line input filtering, as they typically have lower inductance and provide better RFI reduction, and they rarely get leaky with moisture. But I still evaluate and replace if necessary when servicing older equipment.
I prefer to place the hot lead capacitor after the line fuse, and I do not fuse the neutral. Grounded polarized line cord plugs eliminate any issues, so long as the hot and neutral are wired to the correct terminal on the receptacle and the line cord plug.
A little-known fact is that the GFCI protection device will perform its duty, even if there is no ground lead wired to the GFCI receptacle. Of course it is always safer to use a properly grounded receptacle and line cord, but it is interesting to note that if there is a ground fault, through a person's body, or otherwise, this current from the hot lead to ground, whatever path it takes, will trip the GFCI device, even if the device has no ground connection. There is no connection from ground to the circuitry in the GFCI device; it does all its magic by detecting a difference between the neutral and the hot, and the cause of this difference is some of the current on the hot is not returning through the neutral lead in the GFCI device.
Hope this helps, 73, Rick
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