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Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment. |
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26th Jun 2022, 8:35 am | #1 |
Diode
Join Date: Sep 2021
Location: Aberdeen, Aberdeeshire, Scotland, UK.
Posts: 3
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Rotary Transformers
Hi, I'm currently restoring a 1950's Marconi AD118 HF radio. This was an airborne MF and HF radio and used a rotary transformer to generate B+ 230VDC from the nominal 28VDC aircraft supply. A previous owner has removed the transformer and had replaced it with a mains transformer. I'd like to convert the radio back to 28VDC operation and have just rewired all the heaters back to the original series/ parallel arrangement. Just working through all the high resistance and open circuit anode resistors at the moment. I'm looking for a suitable DC-DC converter to replace the rotary converter, needs to supply 225-230VDC at about 200mA. Any suggestions?
Cheers, Ian |
26th Jun 2022, 11:28 am | #2 |
Dekatron
Join Date: Jul 2008
Location: Charmouth, Dorset, UK.
Posts: 3,601
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Re: Rotary Transformers
Just after the war the government surplus shops were full of them, had quite a few myself, I doubt that they are made now, I think your only chance is to find someone who has one left over. Have you had a look on Ebay? I have only seen big 3 phase things on there but if you put a 'saved search' on there you never know.
Peter |
26th Jun 2022, 1:59 pm | #3 |
Moderator
Join Date: Dec 2010
Location: Exeter, Devon and Poole, Dorset UK.
Posts: 6,824
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Re: Rotary Transformers
You could try this one
https://www.ebay.co.uk/itm/334303192...sAAOSwr9xh7pGy I always find its easier to search Dynamotor rather than the term I prefer which is Rotary Transformer. or perhaps this one https://www.ebay.co.uk/itm/353627395...8AAOSw0X9hGpmD https://www.ebay.co.uk/itm/284227956...QAAOSwRrtgV8f- Good luck hope you find something suitable Cheers Mike T
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Invisible airwaves crackle with life or at least they used to Mike T BVWS member. www.cossor.co.uk |
26th Jun 2022, 5:49 pm | #4 |
Diode
Join Date: Sep 2021
Location: Aberdeen, Aberdeeshire, Scotland, UK.
Posts: 3
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Re: Rotary Transformers
Thanks for the responses so far, but I think I didnt explain. I want to replace the rotary transformer, dynomotor with a solid state DC-DC inverter to do the same job. I have been playing with a couple of Chinese modules, but the hash and noise that comes out of them is horrendus. Without shielding them inside a can and adding extra filtering I wondered if anyone could sugest an alternative?
Cheers, Ian |
26th Jun 2022, 8:42 pm | #5 |
Diode
Join Date: Sep 2021
Location: Aberdeen, Aberdeeshire, Scotland, UK.
Posts: 3
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Re: Rotary Transformers
Sorry, I didn't word that too well. I'm looking for a solid state inverter, DC-DC converter, 28VDC to 225-230VDC, to replace the missing Dynamotor.
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27th Jun 2022, 11:19 am | #6 |
Dekatron
Join Date: Jul 2008
Location: Charmouth, Dorset, UK.
Posts: 3,601
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Re: Rotary Transformers
Ah, OK I thought you wanted to restore it to original spec.
Peter |
27th Jun 2022, 7:48 pm | #7 |
Dekatron
Join Date: Jan 2004
Location: Newcastle upon Tyne, Tyne & Wear, UK.
Posts: 8,173
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Re: Rotary Transformers
Hi Ian, you may find modern MIL inverters listed on the auction site. These should be extreamly well filtered
Ed |