Up and running again
Well, I had the system up and running again last night. I used the C.P.
capacitor that I bought from David Lawrence. This came from the original
group purchase by Scotty - and has never been used. I mounted the cap down
lower in the cabinet this time and now my tap lead is back to 36". I had it
down to 24" but was worried that I had the cap mounted up too close to the
bottom of the primary - and of course I still don't know why that last cap
I fired the system at low power (welder set at minimum) and got good results.
The primary current was about 17 amps and we set about trying to find the
best tune. Shortly, the gaps started to fire erratically. I unplugged the
oven elements (6000 watts) that are in parallel with the welder and it ran muc
h better. Primary current jumped up to 20 to 25 amps and the discharge
length almost doubled. The sparks are now much hotter. This is still very
puzzling to me. With the resistors out of the circuit the primary current
should have went down, not up. Must be related to this synergistic tune that
Richard Quick identified earlier.
Now running without the resistors in parallel with the welder, we worked for
about 45 minutes trying various tuning combinations. I am still having
problems with the strikes hitting the primary. Occasionally I would get
thick hot discharges to the strike rail that would stay there for a second or
two - very hot. I do need to build a new flat primary. We did set a new
distance record for this system of 80" and did get the first strikes down to
the earth that I have ever seen. With the welder set at about half power and
about 30 amps of primary current, all of a sudden everything shut down. I
tried to power it up again and get massive primary current, about 40 amps.
The static gap (in series with the rotary) fires but it does not look like
the rotary is firing. It was still spinning. It acted like a high voltage
short somewhere in the primary circuit. We did a close inspection and did
not see any problems. No burn marks anywhere, the rotary looked fine and the
static gap looked good. The cap was still in one piece and the open circuit
resistance checked ok. I don't have any means to measure the value of the
cap. A buddy has a capacitance meter and I will have him check it for me.
The mysteries of life continue.