Now I believe

[ELA]

100405-2026 EST

ELA:
Do you have access to any test equipment to perform more controlled experiments than random switching of an inductive load?

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Gar,
In a previous job I used to have access to many kinds of EMC test equipment as I was tasked with precompliance testing for CE marking of the equipment we built.

Manufacturers of GFCI's for the average market often talk about their ability to pass a Ring-Wave test. This is a high voltage spike with a limited rise time. Many pieces of equipment can pass this test with only an MOV at the input.

For CE marking we also had to withstand an EFT (Electric Fast Transient) test. This test applies high voltage spikes with a fast rise time and also has a "burst requirement". In the burst mode the device under test must withstand a burst of many pulses one right after the other.
This is an excellent test to shake out weaknesses in an EMC design.
If equipment fails this test an MOV alone is not enough. It must be followed by a filter as well.

The advantage of having an EFT generator is adjustability of the test level, repeatability as well as ability to apply the burst.
It is one of my favorite pieces of test equipment and I miss it dearly.
Unfortunately I no longer have access to any of that EMC test equipment.

Every time we talk about suspected EMI issues I long to have access to that equipment once again.

If one were interested you can build an inexpensive transient generator by cross coupling a number of relays in a configuration known as the NEMA Chattering Relay test. This was NEMAs early attempt - prior to introduction of EFT generators.
This can be pretty effective but it may take some time to select the best relays and to characterize the output.

I know you like to use your Fluorescent fixture to generate transients. Have you considered trying oscillating relays to ramdonly open and close the ballast circuit?
I am sure it would be hard on the bulb but might produce the desired output?

 

[gar]

100406-1302 EST

ELA:

From my most recent test it appears the #2 motor starter was a better transient generator than the ballast. This may result from the change of inductance as the contactor solenoid is opening. The amount of inductance in the motor starter is probably less than in the ballast or the 175 VA transformer that I also used.

If I built something it would probably use a step up transformer with solid state control of the primary. For a very fast rise probably capacitor discharge into the primary, did this in the 50s on the development of an ignition system to fire fouled plugs. Otherwise open the primary to produce an inductive kick, an ordinary ignition system, that has a much slower rise.

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[fondini]

This freezer sits adjacent to the " not a basin". I have already had more than one GC sit on it with their feet in the water. Whatever you want to call the room is purely academic. The problem is with the gfci. The reason for switch replacement is to eliminate any noise generated by it during its action.

lol! Took me a minute to realize "gc" was grandchild and not general contractor, and if it is the latter.......