Alternative power for 375 watt 12VDC motor ????

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digitalis49
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Alternative power for 375 watt 12VDC motor ????

Hi all.
I am new to this great forum but have perused it many times past picking up some great knowledge.

PROBLEM:
======
I have a rather heavy trailer dolly fitted with a 375 watt 12vdc down-geared worm drive motor (30amps???).

I know I can mount a 12vdc battery to drive the unit but adding a battery would make the dolly unbearably heavy.

The dolly needs to work approximately 15 ~ 20 minutes per day.

QUESTION:
=======
Can I use a 240vac battery charger (in lieu of a 12v battery) to power the dolly?
I do have an "automatic" 6v/12v, 2A/6A/12A charger which also has a battery start switch.

Is there any other option?

Please, I am not "electrically" minded so your input here will be welcomed.
[Have searched previous posts but nothing found relating to my motor spec]

mf70
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Re: Alternative power for 375 watt 12VDC motor ????

I take it that you would like to switch to mains power and a cord rather than a battery powered setup.

If so, I would advise merely getting a 1/2 HP 110V AC motor. If you need reversibility, some AC motors can handle that. It will be MUCH lighter. Low voltage systems are much less efficient than higher voltage systems.

You may want to revisit the control circuits, however, as the original may not have paid much attention to proper grounding; while less efficient, a 12V system is almost completely safe, and a sloppy 12V design would not compromise safety. A sloppy 110V system could leave you on the damp concrete floor dead.

Mark

digitalis49
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Re: Alternative power for 375 watt 12VDC motor ????

Thanks MF.
I will assuredly leave the electrical wiring to my cousing who is a certified electrician.

Our power here in Australia is 240 VAC, 50Hz.

Can I ask what spec 1/2hp motor would suit? - e.g. capacitor type, amps? watts? rpm & reduction drive type/ratio?

Sorry but you can see here I am no engineer!!

Regards.

Andrew

mf70
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Re: Alternative power for 375 watt 12VDC motor ????

1 Watt = ~700 Watts. Since Watts = Amps * Volts, a 1/2 HP AC motor (~350 Watt) on a 240V line will draw about 1.5A. Metric countries these days express power in BTU; you'll have to get the conversion factor if that's what you need.

The hard part will be finding a reversing AC motor. I know they exist; I don't know how to ask for one. You'll be surprised how small it is; that's the size motor you would find in a healthy kitchen mixer.

MF

digitalis49
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Re: Alternative power for 375 watt 12VDC motor ????

Hi Mark.
Once again, thank you for helping me out.

Can I re-check with you that a 350 watt 1/2 hp motor will have the power to drive a 100:1 worm gear which will then pull and push a tandem-axle caravan weighing 3400 kg's ?

I would be so delighted if it were so!

Andrew.

PS. The 12 vdc-based dolly I have built weighs 35kg's! Most of the weight is the motor and worm drive.

Andrew

mf70
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Re: Alternative power for 375 watt 12VDC motor ????

A Watt is a Watt. If you've got 375 of them, you basically are doing 1/2 HP of work. Assuming the output RPM of the two motors is the same, they will drive the system with the same effectiveness.

Except for the part of the problem where you die if you touch the wrong thing, high voltages are MUCH more efficient than low.

As a way to think of this, remember that one horsepower meant literally that, assuming a rather large dray horse is your motive power. Could you get a moderate sized horse to pull your caravan? Probably so.

We get carried away with our ability to dissipate energy. The times a sports car is actually USING all 300 horses can be counted on the thumbs of one foot. The energy is dissipated in smoke and heat.

Mark

digitalis49
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Re: Alternative power for 375 watt 12VDC motor ????

Thank you so much Mark.

I can now start my search for a suitable motor.

Kindest regards,
Andrew.

PS. These forums are awesome BUT even more so are people like you who give of their time to others.

Andrew

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