online Chinese flybacks with driver questions

JonIverson, Sat Nov 02 2019, 07:34PM

Since my dual 2N3055 driven flyback power supply was accidentally thrown away, I was pondering building another until coming across subject mentioned assemblies. They're on eBay and elsewhere. Looks like various drivers with flybacks. Questions would be:

1) Do these have built in diodes? I DO want to be able to drive a HV multiplier.

2) Performance/ versatility/ durability comments? Any specific recommendations of one over the other, etc? Most seem to fall within the $15-$20 US range. The 3055's with flyback and tripler could output 30-40 KVDC with mA's available. Could one of the prebuilt Chinese units do the same?
Re: online Chinese flybacks with driver questions
Patrick, Sat Nov 02 2019, 10:29PM

Without seeing the Chinese devices its hard to say. Also they are always questionable in real output i think.
Re: online Chinese flybacks with driver questions
MRMILSTAR, Sun Nov 03 2019, 03:28AM

I have one of those 20-stage Chinese Marx generator kits which I built. I had to make a few mods but it works very well and puts out a 12" spark about every 2 seconds. For the HV supply it came with a ZVS driver and a flyback transformer. It is great at powering the Marx generator. I don't know what the voltage output of the flyback is but I am guessing it is 10K - 20K volts. I see many similar combos of a ZVS driver and flyback transformer on E-Bay. They work well.
Re: online Chinese flybacks with driver questions
JonIverson, Sun Nov 03 2019, 03:47AM

MRMILSTAR wrote ...

I have one of those 20-stage Chinese Marx generator kits which I built. I had to make a few mods but it works very well and puts out a 12" spark about every 2 seconds. For the HV supply it came with a ZVS driver and a flyback transformer. It is great at powering the Marx generator. I don't know what the voltage output of the flyback is but I am guessing it is 10K - 20K volts. I see many similar combos of a ZVS driver and flyback transformer on E-Bay. They work well.

Have any links for the Chinese marx? Would love to check one out!
Re: online Chinese flybacks with driver questions
MRMILSTAR, Sun Nov 03 2019, 02:40PM

JonIverson wrote ...

MRMILSTAR wrote ...

I have one of those 20-stage Chinese Marx generator kits which I built. I had to make a few mods but it works very well and puts out a 12" spark about every 2 seconds. For the HV supply it came with a ZVS driver and a flyback transformer. It is great at powering the Marx generator. I don't know what the voltage output of the flyback is but I am guessing it is 10K - 20K volts. I see many similar combos of a ZVS driver and flyback transformer on E-Bay. They work well.

Have any links for the Chinese marx? Would love to check one out!

Here's the one I have.

Link2

I discovered that you must swap the 2 first-stage resistors for higher voltage models. This is because the 2 supplied resistors flash over occasionally and will destroy the ZVS driver. I destroyed the supplied ZVS driver finding this out. With the new resistors it is now very reliable.
Re: online Chinese flybacks with driver questions
JonIverson, Sun Nov 03 2019, 05:13PM

Thanks for the share. I came across that one yesterday in my search. That seems to be the largest they offer. Are the multiplier stages under oil or just air? Looking more closely, it does appear then that the flyback driver does not have built in diodes since it seems to be directly driving the multiplier assembly. If so, I could use the circuit to drive a TV tripler module.
Re: online Chinese flybacks with driver questions
MRMILSTAR, Sun Nov 03 2019, 08:55PM

Its operated in air. This is a Marx generator not a Cockroft-Walton generator. As such, you can't really operate it under oil because of the spark gaps.

The flyback does contain a diode so it is DC output. Almost all flybacks sold today have an internal diode and therefore DC output. You can find NOS AC flybacks on E-Bay for not much money but they are usually so old that the insulation is cracked although they might be repairable. This place also sells AC flybacks although their price seems rather high to me.

Link2
Re: online Chinese flybacks with driver questions
JonIverson, Mon Nov 04 2019, 04:31AM

Too bad. I also misread or didn't read close enough that this was not Cockroft-Walton design.
Have only heard lukewarm info on the firm you mentioned for flybacks, so I think I will look elsewhere. There are also complaints lodged with the US BBB.