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Re: 1/4 wave TC (metering) (fwd)
---------- Forwarded message ----------
Date: Mon, 30 Jul 2007 08:47:03 +0800
From: Peter Terren <pterren@xxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: 1/4 wave TC (metering)
I wouldn't trust any readings with the TC running. High frequency transients
will capacitatively bypass your HV resistors and give marked errors. It may
well be accurate at 60Hz but may be way out when a TC is running. Sometimes
it is just local fields and the meter reads with only one wire connected.
This is much more likely than ferromagnetic resonance IMO.
> ---------- Forwarded message ----------
> Date: Sat, 28 Jul 2007 11:28:18 -0700
> From: Ed Phillips <evp@xxxxxxxxxxx>
> To: Tesla list <tesla@xxxxxxxxxx>
> Subject: Re: 1/4 wave TC (fwd)
> Bart and all
> I have built a meter that appears to work well in measuring high
> voltages. I use a 1 ma movement and a very long string of resistors in a
> voltage devider. The meter is fed through a bridge retifier. I
> calibrated the unit and it appears accurate to about 5%. When the system
> goes into resonance the voltage jumps to about 20kv with 40v input to
> the NST. I would not have believed it."
> I would have. A number of years ago I blew up the 5 kV scale of a
> Simpson 260 measuring the secondary voltage of a 15 kV, 60 ma transformer
> with 0.006 ufd load. Was ramping up the voltage with a variac and the
> thing obviously went into a ferromagnetic resonance mode at around 25
> volts on the primary. Never again! High leakage reactance transformers
> with capacitive loads are tricky things at best.