Salvaging tip wanted

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Hi all

For my latest project, I need to find a PSU which can supply 40-70V DC at ~15A (or lower voltage which can be put in serial).
Since I'm dirt poor, I'm looking to scavenge such a PSU from discarded machines, but the question is, from which kind of machinery can I expect to find these kind of heavy duty PSUs?

All tips are welcome :)

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Old 24 volt telecom rack supplies can usually be strapped for isolated output. Often they have an internal pot to adjust by 5 volts or so. I use two in series for 50 volt battery charging.

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Is the quality the DC output (ripple, etc.) irrelevant?

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Thanks, Dak, cool advice!

mgleep: Yes, nearly so. The controller is made to be used in a semi-noisy environment with long supply cables, so ripple doesn't matter that much.
Also, the motor doesn't need to be super precise.

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My own research seems to indicate that 48V DC is a standard in some places, like LED drivers and, possibly, mobile homes. They can be bought from eBay fairly cheaply and with a relatively high output.

Just in case someone out there should stumble on this thread searching for a solution of their own.

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48vdc is what's known as the "battery feed" voltage in plain old telephone service.

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Back in the old days -48VDC was the battery feed for POTS (plain old telephone service). Then in the 70's (at least when I got involved with it...) 24VDC and even 12VDC, was seeing light for POTS. So, if you want to find -48VDC supplies, look for cobwebs on the equipment. :)

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Is the 15amps a continuous draw, or intermitent? Depending on the duty cycle, you might find that a small SLA battery (or several in series) and a charger can deliver your peak current at a lower overall cost?

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The 15 amps is peak. Average consumption is probably in the order of 3-5A - And the motor doesn't even run all the time.
I've been considering the battery option too. Adds some degree of mobility to my project as well... I'll try to add some prices to see if it's a better option.