Re: New gap design
If you have a few HV diodes laying around just rectify the pig's output and
then run through a high value resistance (like 10 meg) and then to a small
doorknob cap. Hook up a cheap TV HV probe and using a variac slowly bring
up your pig's output. Set your series reactance to a high value also to
help control current on input side to around 10-15 amps max. You will see
the DC voltage displayed on the HV probe meter and you can calibrate for the
10 kV breakover you desire. The peak DC voltage as read on the meter will
be equal to the peaks hit on the AC so the breakdown will be very similar.
It might vary a bit but not much from these values.
This will allow you to check what voltage your sparkgap is firing at. Just
run this without your TC, ie, just the xmfr, rectifier, resistance, and cap
with meter attached. With a large meg resistor it should fire around once
every 2-5 seconds and you can see the value on the HV probe meter.
From: Tesla List <tesla-at-pupman-dot-com>
To: tesla-at-pupman-dot-com <tesla-at-pupman-dot-com>
Date: Tuesday, February 15, 2000 8:46 PM
Subject: New gap design
>Original Poster: Esondrmn-at-aol-dot-com
>As I mentioned the other day, I am designing a new linear gap for my 6"
>running at 7 kva. I am curious to see if this gap will quench and to
>it's performance against my async rotary. I plan to use 11 of the 1.0" dia
>copper tubing coupling pieces for a total of 10 gaps. I will also use a
>vacuum motor to create strong air flow through the gaps - for quenching and
>cooling. I plan to design the gap so the copper pipe sections are gapped
>.030" by using small spacers between them at the ends. By changing these
>spacers, I will be able to adjust the gap distance.
>I am running a 14.4 kv 5kva distribution transformer at about 7 kva. I am
>not exactly sure what the output voltage is but know I have some primary
>losses due to the inductive and resistive ballast. I am also using the
>higher output tap on the variac, so for sake of discussion, let's say the
>output is 15 kv. This would be 21,200 volts peak to peak - so the cap
>charge to one half of this or 10,600 volts. How do I determine how wide I
>want the gaps set to fire at about 10,000 volts? Is the .300" that I have
>How about heat dissipation? How hot is this gap going to get? I recall
>someone saying that the gap eats up about 7% of the available primary
>Is this close? Does that mean that I will have 7% of 7kva or about 500
>dissipated in the gap?
>Thanks, Ed Sonderman