Power 24 volt DC Motor

gwarner

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I picked up an Auto scrubber that had 3 Motors. 1 motor is a .5 HP that drove the machine and 2 .75 HP motors that drove the floor scrub pads. These motors are big and weigh about 40+ pounds each.
They are 24 volt DC. The .5 says it is 320 rpm and 23 amps. The .75 are geared and 200 rpm and 32 Amps.
I don't need to do any speed control but I want to power them from a 120 volt circuit and convert it to 24 volts if possible.
I have found a few converters that go as high as 20 amps but none in the 30 amp range.
Short of hooking them up to batteries what is the best way for me to power these motors.
I want to use them on a mill if possible.

Any thing you guys aware of that is out there?
 
Probably going to have to build something. Might be quite a bit cheaper anyway.
 
Hey there is a thread on here about rewiring a microwave oven transformer for a power supply.
http://www.hobby-machinist.com/threads/rewiring-a-mot-microwave-oven-transformer.57223/
http://www.hobby-machinist.com/thre...rger-from-a-microwave-oven-transformer.57271/

and in fact, that first one goes thru the process of testing the transformer with a few turn to work out the volts per turn. Using that you can figure out the number of turns required for your target output voltage.

ebay would be a good source for a high-current bridge rectifier and capacitors.

It is a total DIY solution, low cost and not overwhelming complexity if you've done any electrical\electronics work before.

-brino

EDIT: you could also check either agricultural or industrial markets for 24V battery chargers that can supply the current you need.
 
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If you were close we could deal for a 24 volt charger from walk behind pallet jacks. Id look into a charger for power wheelchair and scooters. I needed one for a scooter I use , not sure if ebay or amazon. But I think I paid about thirty bucks but not sure of the output on that.
 
Thanks for all the replies. You guys had better luck that what I did. Those are a pricey gamble since I'm not certain the motors will work out for the application.

I like the idea of the 24 volt charger seems that may be an easy find. Will it put out constant voltage to run the motors for a long time?

I do have a larger transformer that I pulled from something. I will test later today to see what it puts out.
I am good with wiring a house but Electronics is my nemesis. I am only good at letting the smoke out.
Brino, I can follow instructions so I may pursue the DIY solution if my Transformer is in the range I'm hoping.
 
Depending on the type of motor the start up current is going to be brutal. Series motors of that size will probably be over 100 amps. At 24 volts this can be tough on switches, contactors, etc.

Now if the actual running load will be much less than the rated that will help. I don't think a normal charge will like this type of load. Also some chargers are "smart" and they won't start unless they see a minimum voltage, this protects everything in case the output terminals get shorted together.

One way would be to use a 24 volt battery (two 12s in series) to handle the peak inrush, and if the running current is low use a charger that can handle the running current.

David
 
A small DC arc/mig welder sounds like just the ticket- they put out about the right voltage and 80 or so amps...
Mark S.
ps those motors sound like they would be more suited to a small electric vehicle rather than a mill.
 
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For testing purposes two 12V automotive batteries in series would give you 24V. You could at least determine if the motors work before you invest money (or time) in a power supply.

Heck you could even try them using just one 12v battery you wouldn't get full power but they should turn.
 
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