Kapanadze Cousin - DALLY FREE ENERGY

[apecore]

Thanks I will try your snubber!

My mosfets are at least 10 inch seperated.....the likely interact on each other if they are closer to each other then 4 inch.

[GeoFusion]

Hi guyz

I am happy to hear these test results on the benches yet it is a challenge.
My snubber's resistors will turn very hot at minutes of drive, the protect the fets for not getting hot.
But eventually they will be so toasted they just die out or pop.

Guyz one more thing want to ask if you guyz are using Over-voltage protection for gates.
two zener diodes facing each other where one anode to source and one anode connected to gate.
Without these my Fets pop immediately.
Cap which I used on my snubber is a 0.33uf 630V poly cap.
yes, make sure the resistors are good in value able to handle the back spikes.

for ones trying with big choke (mediator) I prefer using TV yoke high perm, or some rings of high perm same
dimensions as a yoke.
If you use the Push-pull yoke as the mediator itself the tuning is completely different and that is where Akula
tuning comes in play. very fine one.

[lacphong]

Hi GeoFusion,

Just my 2 cents...
Use bidirectional tvs diode to protect the mosfet gate, but I think the mosfet you're using is too weak, you should measure the voltage at your mosfet gate, and find a more suitable mosfet, else you're wasting efficiency using those zener diode.

As for snubber I think 0.33uF is a little too much, use 2.2nF in series with a 10R 3W resistor.

Hi guyz

I am happy to hear these test results on the benches yet it is a challenge.
My snubber's resistors will turn very hot at minutes of drive, the protect the fets for not getting hot.
But eventually they will be so toasted they just die out or pop.

Guyz one more thing want to ask if you guyz are using Over-voltage protection for gates.
two zener diodes facing each other where one anode to source and one anode connected to gate.
Without these my Fets pop immediately.
Cap which I used on my snubber is a 0.33uf 630V poly cap.
yes, make sure the resistors are good in value able to handle the back spikes.

for ones trying with big choke (mediator) I prefer using TV yoke high perm, or some rings of high perm same
dimensions as a yoke.
If you use the Push-pull yoke as the mediator itself the tuning is completely different and that is where Akula
tuning comes in play. very fine one.

[apecore]

Hi GeoFusion,

Just my 2 cents...
Use bidirectional tvs diode to protect the mosfet gate, but I think the mosfet you're using is too weak, you should measure the voltage at your mosfet gate, and find a more suitable mosfet, else you're wasting efficiency using those zener diode.

As for snubber I think 0.33uF is a little too much, use 2.2nF in series with a 10R 3W resistor.

Geo,
I use also as Lacphong pointed out the bidirectional 18V TVS diodes.
Snubber can do something but are not ment to dissipate lots of power.
It is all about a clean gate dignal....thats what gives control about snubber losses or even burning the fets.
When you have strange peaks on your fet source wich is not generated by gate pulsing you have a gate distortion....
It could be HV ...or interference from the other fet...

Succes

[verpies]

It is all about a clean gate dignal....thats what gives control about snubber losses or even burning the fets.

Not only.

MOSFETs are most frequently damaged by:
1) Gate overvoltage
2) Drain overvoltage
3) Drain overcurrent

While interrupting inductive loads, #2 is the most probable.