Electric wheelchair motors

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rkcarguy
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Re: Electric wheelchair motors

Post by rkcarguy » Tue Aug 28, 2018 10:26 am

My boat is powered by an old Volvo engine and it has a worm gear drive on the electric motor apparatus that raises and lowers the outdrive. It has a slipper clutch on it to prevent it from being damaged and the force it takes to push down on the drive(which pivots it up) is less than 50#'s. Still, when the clutch setup got corroded and seized, it sheared the worm gear right off the end of the shaft.

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BigDumbDinosaur
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Re: Electric wheelchair motors

Post by BigDumbDinosaur » Tue Aug 28, 2018 12:38 pm

SteveM wrote:
Tue Aug 28, 2018 9:20 am
I think that one downside is that the gearboxes can be worm drive, so when you stop the motor, it comes to a halt - there is no coasting.
Not necessarily.

A worm gear drive using a multi-start worm may be reversible. In a worm drive, the gear ratio is defined as N ÷ S, where N is the number of teeth on the gear and S is the number of starts on the worm. In most production gearing, S will be 1-4 inclusive. If a 4-start worm is running on a 24-tooth gear (a not-uncommon combination), the ratio is 6:1, which is reversible.

Multi-start worms are made to an hourglass form, which means they engage more than one tooth on the worm gear, unlike a single-start worm. For this reason, the multi-start worm is preferred in power transmission applications involving high-inertia loads.
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Re: Electric wheelchair motors

Post by Glenn Brooks » Tue Aug 28, 2018 1:46 pm

Being basically illerate about electric motor systems, my basic question is, what size wattage motor should I really be looking at to power a large 0-6-0 switcher - say something 2.5” or 3” scale? I could see pulling as many as 3 or 4 cars possibly weighing up to 5,000 to 6000 pounds max load.

For example, the British 0-6-0 switcher that has caught my eye up at the Victoria (BC) Island Model Engineers uses one electric motor mounted in the cab to power to all the drivers through a flywheel on each side at the rear, with side rods to all the drivers. Double or triple the size of this Loco, what range of electric would be appropriate?

I am guessing 240 Watts isn’t big enuf. Although I suppose I could mount two motors inline, driving a common jack shaft pointing rearward to the drive line. Incidentally, I do have a nice small 90* reduction gear box sitting on the self that might fit.


Thanks
Glenn
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rkcarguy
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Re: Electric wheelchair motors

Post by rkcarguy » Tue Aug 28, 2018 2:12 pm

Question for your question....what kind of grades are we talking about?

http://backyardtrainco.com/powered-trucks/
This guys trucks have TWO 450w 24volt motors per truck(so 1800w total 4 motors) on their 1.6" scale Geep trucks.
More available power = more work capacity and longer equipment life.
At the grades I'm looking to have to pull and weight I want to carry, the torque multiplication of gas/hydraulic was my only option. I'd probably have to triple my budget getting an electric setup that would provide equal output.

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Re: Electric wheelchair motors

Post by Glenn Brooks » Tue Aug 28, 2018 9:40 pm

At Victoria, where this blue 0-6-0 operates, the ruling grade is slightly over 2%. My grades are all around 1%...

The interesting thing about this 0-6-0 is that all the drivers are connected with side rods, that lead back to a fourth axle with a flywheel only, (no wheel) under the cab. The forth axle is then driven by one motor.

Ive emailed them to ask what size the motor is. As this Loco is rather small and light weight, I suspect the controlling parameter with this small engine is the overall weight and associated tractive effort, rather than the size of the motor.

But I need to learn a lot more regarding the relationship between motor size (watts), side rod powered drive wheels, and pulling power...

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Harlock
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Re: Electric wheelchair motors

Post by Harlock » Tue Aug 28, 2018 11:14 pm

For a larger switcher pulling the loads you want, you're looking at a couple of larger motors if you're looking in the 24V range. the most powerful 24V motor I could find was a 900 watter, which is about 37 amps @ 24 volts. I put that in my speeder and I can tow my whole train around the railroad if I need to, I use it when unloading to move the train to the yard as the steam engine has not been fired up.

If you put two of those motors in, you could comfortably haul that load, if you make the engine heavy enough for the traction.

You could also go to 48 volts since in a larger item you'll have room for four batteries, and that will also give you the weight, and the availability of much larger motors.

here's a good place to start looking:

https://electricscooterparts.com/motors.html

here's the 900 watt 24V motor I used in the end:
https://www.monsterscooterparts.com/24- ... ocket.html

For a controller, use a modern industrial controller. I use a SyRen 50A 24V controller. Roy Stevens at Ride Trains sells them with a sound board add on that also includes some safety features such as a power-on throttle lockout and reverse lockout. (slowly comes to a stop if you hit reverse with the throttle open.) https://ridetrains.net/sound-light-motor-control-2.htm

I too would recommend not using a motor gearbox and using chains and sprockets instead, unless you need to integrate into trucks tightly. You will likely need one reduction to a jackshaft, and a second reduction to the axles, as you are typically starting with 1900-2500 RPM motors. I made an excel spreadsheet that auto calculates the resulting MPH based on input motor speed and sprockets. It pretty much came out dead on to calculations, using a GPS app in my phone to measure speed.

If you want to see my speeder project for some ideas, the thread is here: viewtopic.php?f=33&t=99787

I picked up that project from someone else's design, and if I was going to do an electric 0-4-0 again, I would put the jackshaft vertically aligned with the axles at the center, with a chain going out separately to each axle horizontally. That way both axles can be sprung.
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Glenn Brooks
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Re: Electric wheelchair motors

Post by Glenn Brooks » Tue Aug 28, 2018 11:59 pm

Thanks Harlock, very good info. I appreciate the background on your build also.

This gives me a very good source for motors - something to orient my build around.

Glenn
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Re: Electric wheelchair motors

Post by Pontiacguy1 » Wed Aug 29, 2018 7:30 am

from what I've seen from those who build electrics, the ballpark guidelines seem to be: Approximately 300-350 watts per axle for smaller or lighter weight locomotives, and 500 watts per axle for heavy locomotives that are going to be doing heavy pulling. Then gear accordingly so that your top speed is in the 8 MPH range. That seems to be what people seem to be building to in general. A lot of people use one 500 watt motor per axle, or you can use one 900 watt motor per truck for a 4 axle locomotive, or 3 500 watt motors on a 3-axle locomotive. Whatever gets you the power you need. You can use smaller motors if you gear down more. Have pulled about 8 or 9 cars around, along with a couple of passengers, on a 3% grade with a small 4 wheel electric before. It only had one 500 watt motor, and it did fine. Only thing was that it was geared really low so 5 MPH was about the top speed. Perfect for a yard switcher, but a tad bit slow out on the main line. Total weight of that locomotive was about 300 lbs.

Just passin' on what I've picked up from some people who build these things.

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Re: Electric wheelchair motors

Post by Glenn Brooks » Wed Aug 29, 2018 10:06 am

Can you place several motors in series, all driving one jackshaft, such as Harlock described? I wonder if they operate at slightly different speeds, would that be a problem??

The particular Loco I am interested in has all the drivers on each side connected together with side rods, that in turn are driven from one shaft.

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Re: Electric wheelchair motors

Post by Harlock » Wed Aug 29, 2018 11:38 am

You can use multiple motors to drive one jackshaft, yes. The power distribution all evens out on its own. You'd want to buy two identical motors together. I have seen several examples of two motors driving a single shaft, no problems. Some controllers have multiple motor outputs, some can be slaved together, or a single high amperage controller can run multiple lower amperage motors as if they were one. The last option is how we run my friend's west valley electric on a single 50A SyRen controller. Four small motors, one on each axle. Each motor is 12V, so two motors on each axle run in series, and the two trucks run in parallel. All works. Just add up the amperage and make sure it doesn't exceed the controller's output. At the same time, make sure the controller isn't wildly overpowered compared to your motors, although most have motor overcurrent protection these days. The only way to kill an electric motor is to stall on a grade with full power going into the motor. Then the windings are heating up but the internal fan isn't running. My controller will cut out in that situation.

Two motors with one jackshaft is really the same as driving multiple motors on different axles. They will turn against the load evenly. If one motor is for some reason slightly weaker than the other, the strong one will pick up the slack...
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cbrew
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Re: Electric wheelchair motors

Post by cbrew » Wed Aug 29, 2018 12:07 pm

Harlock wrote:
Wed Aug 29, 2018 11:38 am
You can use multiple motors to drive one jackshaft, yes. The power distribution all evens out on its own. You'd want to buy two identical motors together. I have seen several examples of two motors driving a single shaft, no problems. Some controllers have multiple motor outputs, some can be slaved together, or a single high amperage controller can run multiple lower amperage motors as if they were one. The last option is how we run my friend's west valley electric on a single 50A SyRen controller. Four small motors, one on each axle. Each motor is 12V, so two motors on each axle run in series, and the two trucks run in parallel. All works. Just add up the amperage and make sure it doesn't exceed the controller's output. At the same time, make sure the controller isn't wildly overpowered compared to your motors, although most have motor overcurrent protection these days. The only way to kill an electric motor is to stall on a grade with full power going into the motor. Then the windings are heating up but the internal fan isn't running. My controller will cut out in that situation.

Two motors with one jackshaft is really the same as driving multiple motors on different axles. They will turn against the load evenly. If one motor is for some reason slightly weaker than the other, the strong one will pick up the slack...
just a couple things to keep in mind when running 2 12v motors in series. if one opens up, they both die. if one shorts. the other sees all 24v, in turning cooking it.
it is also a good idea to run as large (power rating) as possible. its better to have a slippery locomotive vs one you can stall.
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Re: Electric wheelchair motors

Post by Mr Ron » Wed Aug 29, 2018 12:28 pm

Would a golf cart motor work? They definitely have the power, but they might be too large for a 1/8 scale engine.
Mr.Ron from South Mississippi

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