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Sourcing 24vdc 100a Power Supply?

steamandsteel

Aluminum
Joined
Oct 21, 2017
Location
Wichita, KS
Hello,

I’m looking to power an old Autocrane, and would like to have it powered by 110/220 from residential service.

It’s a 24v unit, has three DC gearmotors, would 100a be enough?

However, searching around, I can’t find a suitable means of producing that amount of current.

Is “power supply” even the right terminology, or should I be looking for a rectifier/inverter/generator?

I’d rather not buy the original setup with two 12v battteries, or a giant 24v battery just to power this crane. It would be nice to shave some weight off the unit.

Curious for some feedback,

Thanks
 
. . .It’s a 24v unit, has three DC gearmotors, would 100a be enough?. . .

Impossible to say without knowing the specs on the motors. Regarding power, you might get away with using a 24V battery charger if you can find one of the older type that isn't too smart for its own good. You would also have to consider the control system since the old battery chargers are often not full-wave, buffered or regulated very well
 
No , the draw will be over 200 amps, use a battery and charger...cheap and easy...Phil

what he said.

The batteries are "filters" - allowing a simpler AC power source - as well as buffers. They serve as the source of peak power for what is not a 100% duty-cycle load. That's why we call them "storage" batteries.

:)

Whilst not active, a much lower amperage charger replenishes what was demanded.

Two common 12 V "dual use" AKA deep discharge and/or motor starting units found in any autoparts store as "marine/RV" batteries, connected in series might be all you need.

Two also cheap and common 12V chargers should carry average use. My modest needs, I use the tiny "maintainer" ones, about TWO amps, if-even ...but connected 24 X 7 x 365, whereas the load needs power only every week or three.

The "power pack" of charged batteries can be "remoted" from the load motors.
"Welding cable" has the flexibility that jumper cables or fixed wiring goods do not have.

Better yet? Restore the rig to OEM "as built" and JF use it as designed.

Somebody did their homework and tested all of it before it was put into series production and shipped.

Why mess if you have fewer resources for that research and safety testing than they had?
 
A "buzz box" stick welder power box would do. Get the one with the AC/DC switch. I think they are red ;-)
 
A "buzz box" stick welder power box would do. Get the one with the AC/DC switch. I think they are red ;-)

These are typically 40-45 volts. A load may drag it down to 24, but overall there are better solutions.

Look around electronic surplus stores. sometimes you can find such supplies for trivial prices, but make sure you have the power to run it. I have one similar to -Snowman's suggestion that requires three phase.

Bill
 
I suspect an Auto Crane is meant to be run by batteries which are under constant charge by the vehicle's engine running a big truck alternator. Running from the batteries without the big current supply from the alternator would probably mean a short working period before the voltage drops below that needed to run the crane. Using a really big battery charger to substitute for the vehicle's engine and charging circuit could work. A little car charger would not likely keep the battery up while using the crane unless the lifting cycle is very short.

Here is the current Auto Crane electric unit:
EC-2x – Auto Crane

Larry
 
These are typically 40-45 volts. A load may drag it down to 24, but overall there are better solutions.

Look around electronic surplus stores. sometimes you can find such supplies for trivial prices, but make sure you have the power to run it. I have one similar to -Snowman's suggestion that requires three phase.

Bill

Yup, I've got a three phase motor driven battery charger in the shop basement. Came from a tow-motor warehouse stacker.


Lots of amps available .

Electronics surplus store? I haven't seen such a thing around here in over 30 years.
 
Yup, I've got a three phase motor driven battery charger in the shop basement. Came from a tow-motor warehouse stacker.


Lots of amps available .

Electronics surplus store? I haven't seen such a thing around here in over 30 years.

Gateway Electronics is the last one in the St. Louis area. The last time I was in the Electronics Exchange the owner said that all he sold anymore was video games and CDs. Then he closed. When I got my Amateur Radio license in 1951, a ham could build equipment that had performance comparable to commercial offerings. Now the only people experimenting I know of are the microwave guys. There are still people building equipment in companies but they just send a request to purchasing who forwards it to Newark, Mouser, Allied, or whatever and the parts arrive the next morning. We don't even have regular electronics stores here. Van Sickle Industrial Electronics hung on until a couple of years ago but they faded away like the rest.

Bill
 
A MIG welder can do it, but you have to be careful. I agree with the motor driving some alternators approach, or a small engine driving a few alternators if more convenient.
 
Thanks for all the replies, seems like a pair of 12v batteries in series will be the most economical and practical option.

I think originally the system used one 12v battery, and then the truck alternator as the other half of the 24v equation.. it was a weird setup.
 
Thanks for all the replies, seems like a pair of 12v batteries in series will be the most economical and practical option.

I think originally the system used one 12v battery, and then the truck alternator as the other half of the 24v equation.. it was a weird setup.

24 V batteries exist. Diesel-engined trucks commonly have 24 V starting systems, twin 12V, sometime dual pairs of them.

Alternator in series atop a 12 V would not be common, nor easily kept in good order. Center-tapping a dual 12 V, batteries in series for 12 or 24, is saner and more likely if the full 24 were not used.

Typical alternator depends on the regulator to set the Voltage, is itself capable of far higher Voltages than batteries WANT.

Meanwhile, DC motors run on any Voltage from nominal plus mebbe 50 % down to about ten percent of nominal.

A modest hoist could have done a lot of its lesser-loaded work at only 12 VDC or even 8 to 10. Just slower. Sometimes "slow" is what you actually WANT, too, for finesse as to control.

Selecting a tap is less wasteful than heating of a current-limiting rheostat or the cost of a variable-voltage switched-mode power controller,

That could be a part of the "weird" that isn't so weird after all - just clever economy?
 








 
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