[Prev][Next][Index][Thread]
NEON AND SHUNTS?
----------
From: Thomas McGahee [SMTP:tom_mcgahee-at-sigmais-dot-com]
Sent: Thursday, January 29, 1998 7:58 AM
To: Tesla List
Subject: Re: NEON AND SHUNTS?
> From: Zuma [SMTP:mwise-at-ns.sosis-dot-com]
> Sent: Wednesday, January 28, 1998 8:40 PM
> To: tesla-at-pupman-dot-com
> Subject: NEON AND SHUNTS?
>
> I posted an e-mail a while back on my 12kv-at-60ma neon that I unpotted and
> modified. I stepped up the insulation around the primary and both of the
> secondaries. I also removed some shunts. The tranny had 4 sets of 23
> shunts, I removed 2 shunts from each set. That leaving 4 sets of 21
> shunts. In my post I stated that when I run the tranny the primary
> heats up. It gets hot but not so hot it burns when you touch it.
> I am wondering if anyone might have an idea if this is going to be ok
> and would also like to know what kind of current this thing might be
> giving off now? I was told that it is probably just heating from the
> extra current it pushing out, which makes sense because I noticed that
> after a while the power cord began to heat up. I don't think it is
> shorting at the primary because I had a problem once with a 15kv-at-30ma
> neon that smoked within a minute because it was shorted.
>
> ADVICE IS NEEDED, PLEASE
>
> Chris
>
Chris,
Easiest way to find out what the output current is would be to stick
a 100 ma current meter between the case and one HV bushing. Plug 'er
in and read the meter. I usually use a dumb old D'arsonval type meter
that I pulled out of a piece of junk years ago. The tranny is
current limited, so don't worry about damaging the meter. The voltage
across the meter will only be a fraction of a volt.
Don't have a current meter? Then use a volt meter. To use a volt meter
to measure current you need to measure the voltage drop across a
known resistor. If you use a ten ohm resistor, then 1 volt will equal
100 ma. With a 1K resistor 100 ma will produce 100 volts.
Please note that you have to have a resistor that can dissipate the power:
Power_in_watts=Current_in_amps*Current_in_amps*Resistance_in_ohms
-or- you can use the formula:
Power_in_watts=Voltage_drop_in_volts*Current_in_amps.
The smaller the resistor you use, the lower the wattage rating you will
need. The ten ohm resistor would only have to have a 1/10th watt
rating at 100 ma, but the 1K resistor would have to have a 10 watt rating
at 100 ma. Go for a 10 ohm 1/4 watt resistor. They are dirt cheap.
This at first seems weird to many coilers, but remember that the NST
is current limited. Into a dead short it will deliver full rated current
at zero volts.
Hope this helps.
Fr. Tom McGahee