| plate_follower |
I'm thinking of finally completing the project that I've been working on for the last five years. I have four Eimac 3CX350F triodes wired in PP with two tubes per channel. The heater voltage is not an issue, but the high voltage needed to get the tubes going well is challenging with the inefficient means of stepping up the 12v supply as far as I've been able to figure out.
I have an ambulance alternator that I plan to install on my Suburban that yields 48 volts to support an easier means of getting the voltage high enough. But the real issue us that I want at least 1200v at the anodes for B+. The 300 watt region is possible with these triodes.
SS voltage converters won't do it for me. What about using a pair of HV transformers after an AC generator? My other idea is to create an AC voltage using triacs, or a even an old electric folk lift voltage motor control block.
Anyway, I've been doing this for some time, and still have this unit on my rack with quite a few other projects. The voltage control is the largest issue. Vibration control is a non-issue now with the suspension deck that I milled, and the cooling is simple with a few fans under the sockets for forced air cooling.
Thanks for any advice.
Mike |
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| dangus |
| Alternators (as you might suspect from the name) actually produce alternating current. They turn it into DC with a bunch of rectifier diodes. So.... if you pick off the AC from before the rectifiers, you could feed that to a step-up transformer. |
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| djQUAN |
| quote: | Originally posted by dangus
Alternators (as you might suspect from the name) actually produce alternating current. They turn it into DC with a bunch of rectifier diodes. So.... if you pick off the AC from before the rectifiers, you could feed that to a step-up transformer. |
most alternators also output three phase AC. |
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| NotInTheMafia |
I have seen a car alt re-wound for higher voltage and single phase, i dont think it was that hard to do...
Search around on the net for turning a lawnmower into a generator. I think thats how i happened on it. it used a rewound alt. Wind it for about 110 v and add some microwave oven transformers. |
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| DigitalJunkie |
Rgular transformers probably won't work,considering the higher frequency of the alternators output.
I'm not entirely sure what the freq. is,but it varies with engine speed..I'll guestimate ~400hz with the engine at idle. :confused:
So,You'll need transformers that will work from ~400hz and up (to maybe 2khz?)
So your average 50/60Hz transformer isn't gonna cut it.
Just another point to consider. |
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| Eva |
I would go for a push-pull SMPS with several small transformers with their outputs combined in series, each one having independent secondary side rectifiers and filter capacitors. Consider for example 10 small 10:1 toroids (1 inch diameter) producing 120V each and 1200V when combined in series. For a 100Khz switching frequency turn count requirements would be something like 6+6:60 for each core. By the way, such an arrangement would allow to obtain lower voltages in 120V steps (quite useful, I think).
More traditional solutions are going to be bulky, noisy, heavy, inefficient and/or they will involve doing serious modifications to the vehicle. |
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| ANALOG GUY |
I received PCB design from my Master of Tube Car Amplifier
It can drive more 600V/100mA and 12.6V/6A
I tested with EL34 PP by used schematic of Antique Sound Lab AQ1003 it work very well !
In my suggestion if we can find more power core such as PQ core type PQ35/35 or PQ40/40 it will be support with 500 watts power consumtion !
Regard
analog guy |
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