Author Topic: tungar charger and diodes  (Read 1146 times)

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Offline delta75

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tungar charger and diodes
« on: January 18, 2012, 11:12:21 PM »
Hi all,
         Recently my tungar valve battery charger's tungar rectifier died. I ordered a replacement from the states, but it arrived with a blown filament. High current diodes are expensive, so i had the idea of parrallel diodes to increase the current.Searching google i get two opinions some people say it would work as long as you use the exact same parts, but other say due one diode heating up more that would get more current and blow it, which is right , and how else can i increase the current
thanks delta75

Offline amspire

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Re: tungar charger and diodes
« Reply #1 on: January 18, 2012, 11:29:02 PM »
I had never heard of a Tungar Bulb before, so here is the manual for anyone else who is interested:

http://www.radiomuseum.org/dsp_multipage_pdf.cfm?pdf=tungar_bulb_data_manual_52410.pdf

Is the charger just the transformer and the Tungar rectifier? Which model rectifier does it use?

Offline delta75

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Re: tungar charger and diodes
« Reply #2 on: January 18, 2012, 11:44:28 PM »
the charger is basically a multitapped transformer going to a heavy duty rotary switch( made on a piece of absetos 6mm thick)then to the tungar rectifier,it was an ex raaf charger from the 40's .I have never had to change the valve till now, and their is no markings visible except 'L' anymore, the replacement from the states was a bit of a guess it looked right,

Offline amspire

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Re: tungar charger and diodes
« Reply #3 on: January 18, 2012, 11:59:06 PM »
And do you want to get it going again with valve rectifiers, or can you use semiconductor rectifiers?

I guess to get the same voltage drop, you would need 10 or more silicon diodes in series, and perhaps a bit of resistance as well.

Offline delta75

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Re: tungar charger and diodes
« Reply #4 on: January 19, 2012, 12:06:48 AM »
I wanted to get it going with valves but couldn't find a suitable affordable valve. So i thought i would replace them with diodes but high current diodes are expensive,

Offline amspire

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Re: tungar charger and diodes
« Reply #5 on: January 19, 2012, 12:17:05 AM »
I wanted to get it going with valves but couldn't find a suitable affordable valve. So i thought i would replace them with diodes but high current diodes are expensive,

You are talking about vacuum tube diodes? I do not think you can use them as they will have a higher forward voltage. It has to be a gas/mercury type tube like the Tungar bulbs if you are going to use tube technology.

If you want to go to semiconductor diodes, they could be economical, but it depends on the current. It sound like a half wave rectifier with only one Tungar bulb. And how much charging current ? 10A? What is the battery voltage?


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