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Vintage Test Gear and Workshop Equipment For discussions about vintage test gear and workshop equipment such as coil winders. |
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16th Apr 2017, 6:03 pm | #1 |
Dekatron
Join Date: Aug 2016
Location: Colchester, Essex, UK.
Posts: 4,106
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F C Heayberd Battery Charger
Just got one of these (early 1950's ?) battery chargers with 2v/6v and 12v taps, a sizeable Automat rectifier and an even more sizeable transformer. I really wasn't expecting it to be serviceable and had it in mind to equip it newer components as necessary, but having started with 14v AC from a wall wart a trickle of DC came out the other end, so having done some continuity checks i plugged it into an RCD and got 18v o/c on the highest tapping, which when put to use managed to pump 1.5A into a (loose) car battery.
The transformer is virtually silent, presumably due to good damping/mounting, and we took the opportunity to 'scope the output, which was a good clean full wave DC. Given a modern mains cable and replacement of some of the heat resistant sheaths inside it seems it will be fine for use, but I just thought to query the following: --Is 18v reasonable as an o/c voltage on the 12v output? --The current regulator is a bobbin shaped super-coiled heater, with a layer of asbestos underneath the coil. Is there any recommended goo or solution to provide some medium-term stability to the asbestos which won't oxidise and create a stink when I switch it on? If it wasn't for the heating aspect I would use PVA without hesitation- but I don't know if it can 'take the heat' Thanks |
16th Apr 2017, 6:38 pm | #2 |
Dekatron
Join Date: Jun 2009
Location: Staffordshire Moorlands, UK.
Posts: 5,270
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Re: F C Heayberd Battery Charger
I'd have thought 18V is ok. It might confuse your meter if it isn't a true rms meter anyway as it isn't pure dc. I'd say the asbestos would be ok if you leave it alone. It's heat resisting properties are why it's there.
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Kevin |
16th Apr 2017, 6:53 pm | #3 |
Dekatron
Join Date: Aug 2016
Location: Colchester, Essex, UK.
Posts: 4,106
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Re: F C Heayberd Battery Charger
Good point, the output isn't smoothed and the meter was a similar age to the battery charger, so may just have been measuring the peaks.
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