Re: Terry RF filter problem solved..heh

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Terry Fritz" <twftesla-at-uswest-dot-net>

Hi Jonathan,

At 04:07 PM 4/28/2001 -0700, you wrote:
>Hi All,
>
>Got my DMM back, and quickly discovered what the problem with my Terry RF
>filter was. The standoffs I put the 1k 100 watt resistors on were insulated!
>It sure *looked* like the brass threaded bit went all the way through... ;-0
>A jumper wire soon solved that!
>

Cool!

>Coil works great with it. BTW, the MOVs tested open (infinite resisuance) is
>this normal? How does one test those suckers?

You would need a current limited HV supply with metering or some other
rather elaborate thing.  Unless they are all cracked and looked "cooked"
they are fine.  You can also measure the capacitance across them and
compare that to a known good one.  However, they don't blow up easily at
all so no worries.  Normally they will look open until the voltage gets to
about 1800 volts when they turn on as a hard short until the voltage drops
back below 1800.  They are perfect for this stuff but a little pricey.

I blow a MOV string once while doing something "creative" :-)  They get
super hot and smoke and their voltage drops way down.  The damage is not
hard to see.  However, they continue to protect even while they are burning
up and will only let the HV through when they actually burn up and fall out
of the circuit.

Cheers,

	Terry


>
>Thanks
>
>Jonathan Peakall
>