Akula0083 30 Watt Self Running Generator.

[lost_bro]

Addendum.  Silly me !! Ch1 input signal to L1. Ch2 output signal from L2 on to input of FWBR. 
[/quote]

Hello Grum:
Thanks for posting the o-scope shot:

OK, are you using a square wave to drive L1 on the scope shot?

What are you using to generate the driving signal for L1.

I will only comment that the driving signal *should* be as clean as possible......

I don't see the square wave there at all, maybe I'm not seeing this correctly.

Take care, peace
lost_bro

EDIT  , another queston, since you are driving an inductive load, are you using a Freewheeling diode across the inductor/MOSFET? 

If not, that by itself will inject *a lot* of noise into the driving signal and quite possible fry the MOSFET.

[Grumage]

Dear All.

"It takes all sorts to make a world" something my dear Grandmother often said to me when I was young !!

I feel there is a wealth of experience here at OU.Com, keep it coming !!

Best wishes and good luck to all, Grum.

[Grumage]

Addendum.  Silly me !! Ch1 input signal to L1. Ch2 output signal from L2 on to input of FWBR. 


Hello Grum:
Thanks for posting the o-scope shot:

OK, are you using a square wave to drive L1 on the scope shot?

What are you using to generate the driving signal for L1.

I will only comment that the driving signal *should* be as clean as possible......

I don't see the square wave there at all, maybe I'm not seeing this correctly.

Take care, peace
lost_bro

EDIT  , another queston, since you are driving an inductive load, are you using a Freewheeling diode across the inductor/MOSFET? 

If not, that by itself will inject *a lot* of noise into the driving signal and quite possible fry the MOSFET.

Dear lost_bro.

I am driving the transformer with an older type of RM Cybernetics PWM's  this unit has now been superseded by a much more robust design !! However the new design has a current limit device which seems to alter the effects I am seeing. As to the transistor I have no idea at this moment!!

My duty cycle is very low probably much less than 10% . I am just hitting it with little pulses "ah la" Tesla style !!

I have attached the pdf that was available when the PWM was in production. You may then be able to have a better idea of how I am driving the transformer.

Cheers Grum.

[lost_bro]

Dear lost_bro.

I am driving the transformer with an older type of RM Cybernetics PWM's  this unit has now been superseded by a much more robust design !! However the new design has a current limit device which seems to alter the effects I am seeing. As to the transistor I have no idea at this moment!!

My duty cycle is very low probably much less than 10% . I am just hitting it with little pulses "ah la" Tesla style !!

I have attached the pdf that was available when the PWM was in production. You may then be able to have a better idea of how I am driving the transformer.

Cheers Grum.

Hello Grum

Thanks for sending a copy of the PWM manual.
OK:

Driving Inductive Loads (Motors, Solenoids, Transformers, Relays, Coils, etc)

The PWM-OCB has only basic protection against high voltage transients from inductive loads.
When driving inductive loads you should take extra measures (detailed below) to protect the
OCB from high voltage transients. This unit is not suitable for use with ignition coils. You
should use the other more advanced models such as the OCBI, or OCXI for such loads.

Place a fast diode such as a schottky diode in parallel with the load input terminals as close to
it as possible. If you are using a switch to reverse the direction of a motor, the diode should
be placed just before the switch, between the switch and the OCB. See figure 3.


Yes, that is from page 5 and they are referring to a Freewheeling diode. 
That diode will help keep from heating up and destroying your MOSFET in the PWM.   Otherwise know as an Inductive Kickback diode, it makes a path for the *back*EMF to bypass the current when the inductor is off, as the current lags in an inductor.

**EDIT, maybe it is this same lagging current from L1 that we want to channel somewhere else for this purpose?

Wow now I'm not real sure.....

My duty cycle is very low probably much less than 10% . I am just hitting it with little pulses "ah la" Tesla style !!

If you hit with 50% duty cycle, will the MOSFET heat up?

take care, peace
lost_bro

[From other Planet]

Periodically we are going to refresh the front page and the schematic we are working to duplicate, to keep the forum on the rails.
No need to worry

So the actual schematic still hasnt the ground connection on the other side of the voltagedivider and the LED? Seems strange to me. Anyone tested if its working this way? Cant imagine that unless pin 16 of TL494 is able to provide a ground somehow... Or am i totally wrong? Maybe one of  the pros here like verpies or TK can have a look at this and give a statement?