Original poster: "Qndre Qndre" <qndre_encrypt@xxxxxxxxxxx>
Hey.
Let's check your circuit step by step. Since
this issue can be caused by almost anything
we'll check each and every single component till
we get the one which is not functional. This can
be much of work but since the issue seems to be
pretty hard to locate, I don't see any alternative to this method.
1. Wiring: If it's a center-tapped secondary
with the center tap connected to RF-ground (NO
connection to mains-ground!!), midpoint-grounded
like you said, you can NOT ground one end of the
secondary as well as this will short out half of
your secondary winding. Do not ground any of the
hot wires but only the center tap which will
give you two hot wires, each having 5 kiloVolts
in reference to ground being 180° out of phase,
having 10 kiloVolts between both hot wires. Now
connect these two hot wires to the main spark
gap (with a Terry-Filter in between if you want
to protect your mains transformer from the RF).
Now wire primary coil and primary capacitor in
series forming the LC-circuit which should then
be wired in parallel to the spark gap.
2. Mains transformer: You should be able to get
an arc between two pieces of wire connected to
the high-voltage output if distance is close
enough. If you get an arc, we're going to check the next component.
3. RF filter / NST protection / etc.: Hook up
your protection circuits to your transformer but
nothing else. Power it up and see if they have
internal shorts etc. which will make your
transformer hum or the faulty component burn. ;)
4. Spark gap: This should not be conducting
unless it's firing voltage is reached. Hook the
spark gap up to a low-voltage power-supply. You
should not have any current flowing through it.
If current flows, you have an internal shorting
(electrodes touching each other) or a carbonized
path somewhere. If it looks OK at low voltages,
hook it up to your mains transformer together
with your current-limiting. The voltage should
be high enough to make it fire. If not you have
to reduce the distance between the electrodes.
If it fires we're going to check the next component.
5. Capacitor: If using an MMC you can try to
charge every single cap using low-voltage DC and
measure it's voltage to see if it holds it.
Don't forget to discharge every cap after this
since you have many caps in series in your MMC
so you can get hazardous voltages across the
whole circuit since the voltages of all the caps
in series will sum up. Also remember that caps
can regain charge from dielectric memory. If all
the caps hold the charge properly we're going to
check the next component. This measurement can
be a bit harder if you have bleeder resistors across your caps.
6. Primary coil: This should be rather
conductive. If it isn't, there's something wrong with it.
7. Secondary circuit: If you still don't get any
output, there's something wrong with the tuning,
the coupling, the secondary is broken somehow or
doesn't have a good connection to RF-ground and
the topload capacitor. Check your secondary
circuit. If you are absolutely not sure if you
manage to achieve resonance between primary and
secondary circuit you can try to measure the
resonant frequencies of both using a frequency
generator and an oscilloscope. The coupling is
usually increased until you get racing arcs,
then it's decreased a bit to achieve "perfect" coupling.
Regards, Q.
----Original Message Follows----
From: "Tesla list" <tesla@xxxxxxxxxx>
To: tesla@xxxxxxxxxx
Subject: Re: tesla coil does not work...
Date: Thu, 12 Jan 2006 19:35:57 -0700
Original poster: "Langer Giv'r" <transworldsnowboarding19@xxxxxxxxxxx>
its a double pole xfrm with mid point ground
connected to the ground on my safety gap, and
the two hot wires are connected in series with
the LC ciruit, and in paralell with the main spark gap