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Permanent Magnet DC Regulator

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I did some testing... and here are the results:


1. The voltage limit circuit works within 0.2v of the zener diode voltage
2. V at the Collector is 14.xv
3. V at the Base is 2.x
4. Emitter is grounded.

Now everything works perfectly until I put a small load on the collector and emitter....

A small bulb rated at 12v, 18w... what happens is that all of a sudden the transistor dies... and eventually the zener burns too... when this happens.. the bulb also burns out since.. the voltage goes back to the unregulated above 30v.

on the 2nd experiment, knowing that I could burn another bulb... I connected the bulb for a very very short time, a fraction of a second.. and the again the transistor dies.

It seems the sudden load/unload creates a voltage spike that nukes the transistor.
 
icedeocampo said:
I did some testing... and here are the results:


1. The voltage limit circuit works within 0.2v of the zener diode voltage
2. V at the Collector is 14.xv
3. V at the Base is 2.x
4. Emitter is grounded.

The base voltage sounds far too high?, it should be about 0.7V.
 
ok i've tested it again, and the voltage at the base is very near 0.7, swings from 0.6 to a little over 0.8v

but the voltage really moves quickly, because of the change of engine RPM.

the circuit works... and gets very warm ^_^... but I think the big heatsink can now handle the heat.

Now... I'm going to try to experiment on the load later...
 
I still have that issue of the transistor burning out if I don't put a 3k resistor parallel to the load. Can you help me explain this strange thing. It might have something to do with the internal resistance of the transistor.

Even if i use a setup with 1 or 2 transistors, the circuit still needs that 3k resistor. But If have that parallel to my load, and I turn the power supply off... what would happen If my load was actually a battery? would a 3k resistor discharge the battery?
 
icedeocampo said:
I still have that issue of the transistor burning out if I don't put a 3k resistor parallel to the load. Can you help me explain this strange thing. It might have something to do with the internal resistance of the transistor.

If it fixes the problem, then fit the resistor!.

Even if i use a setup with 1 or 2 transistors, the circuit still needs that 3k resistor. But If have that parallel to my load, and I turn the power supply off... what would happen If my load was actually a battery? would a 3k resistor discharge the battery?

Only very, very, slowly!.

Are you saying you've never had the battery connected during your tests?, that could well be a reason for blowing it up!.
 
When I was testing initially I did not connect the battery to the circuit... I ended up with a very very hot transistor and heatsink....

Eventually I connected the circuit to the battery... and the battery charged... but every so often... when I pressed the break lever, which lights the break bulb... the transistor dies

Without the battery... If I connect a load (a light bulb) to the circuit the transistor instantly dies... but with the battery ... the chances of the transistor getting fried dropped significantly.

With the resistor though, the transistor no longer gets fried. I don't know why :(

The reason I was getting crazy readings a few weeks ago was because I was connecting load which caused the transistor to fry... which in turns fries the zener diode.

But...

I can already smell success... Thanks to your inputs! :)
 
bridge will not work, only half phase will

the stator and the battery have a common ground, at the negative phase of the stator, your bridge diode will short itself to ground though other diodes, you can only aply bridge if you float the stator, meaning removing the ground, thats why you produce alot of heat the diode is shorting its self on negative cycles. so DO NOT bridge the stator output with bridged diodes.

the stator coil doesn't really have a high current and low current windings, its actually one coil with a tap, the yellow wire is actually lower in voltage than the white wire, the yellow wire is tapped way in the middle or the whole windings.

the stock regulator only regulates the postitive cycle of the stator, so bridged (even floating will not work), half phase will, remember the negative phase of the stator will swing full peak unregulated and the positive cycle is voltage regulated, you can make use of positive phase when you can design you own regulator with yellow and black wire still attached to your stock regulator the regulate that cycle.

of course it will be half cycle only.
 
hi, when i saw you diagram, its going to break your base emmiter junction of Q1, base emiiters only need small currents.
 
hmm... i'll be trying to do this using 2n3055

the voltage swings from 14v to 60v so I guess this transistor would be enough.

What would be the ideal resistance value of the resistor?

I was thinking... instead of using 2n3055 can i simply reverse everything and use a PNP Transistor and reverse everything so that I can put the collector heatsink as ground to the chasis?

Would I need to put a Diode if I want to Tap ve+ and ve- to the battery?

Again thanks for the super fast replies!

Here's what I have in mind (Ignore R2) would this work?

zener-replacement-gif.12596

sorry for repost..
hi, when i saw you diagram, its going to break your base emmiter junction of Q1, base emiiters only need small currents. the diagram looks like the power is directed to ground from emitter through z1! shunt regulators are better of with SCRs less heat!
 
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