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Old 07-06-2019, 06:18 PM
N!ck N!ck is offline
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Default Possible Electric Engine????

Havenít used this forum in a while and Iíve only used it once before so bear with me please.

I pulled an electric motor out of a treadmill a year or so ago and havenít really done anything with it. Before I invest money into building a frame and getting batteries or whatever, I was wondering if the torque of the motor will be enough to push 200lbs.

So the specs go: 2 hp max, 6000 rpm max, 1.8 torque max, 14 amps, 120 volts.

I have no idea how any of this works so maybe you guys could help me out if it isnít too much trouble.

I should also note that gear ratios and tire size is all undetermined so they can significantly vary. Iím only really interested in if the motor could even move me.

Thanks for the help, cheers!
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Old 07-06-2019, 06:34 PM
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You'd need probably a 12-15:1 gear ratio to make it run, and it wouldn't be real fast at just 1600 watts, when you consider the kart, rider, and batteries.

And 10: 12v batteries in series. A simple speed control like the old golf cars used would work... Basically a rotary switch that selects between battery taps.

It really wouldn't be a GOOD motor though.
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Old 07-06-2019, 06:54 PM
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If I say, hooked this up to my bike resulting in like 180lbs, would 26Ē wheels decrease torque far too much to move me at any significant pace or would the speed from pretty large wheels make up for that? Just food for thought.

Also, would I be correct in assuming that larger wheels decrease torque but increase ground cover in a certain amount of time while smaller wheels would do the exact opposite?

Also also, 12-15 gears on the wheel per 1 on the motor right?

Also also also ó thanks.
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Old 07-06-2019, 07:06 PM
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Quote:
Originally Posted by anickode View Post
You'd need probably a 12-15:1 gear ratio to make it run, and it wouldn't be real fast at just 1600 watts, when you consider the kart, rider, and batteries.

And 10: 12v batteries in series. A simple speed control like the old golf cars used would work... Basically a rotary switch that selects between battery taps.

It really wouldn't be a GOOD motor though.
ERH! Wrong!
It's an AC motor, so unfeasible for a kart.
Unless you feel like having a corded go kart.....
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Old 07-06-2019, 07:16 PM
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Itís dc. Idk why theyíd make a motor that plugs into a wall outlet dc instead of ac but there were a ton of weird adaptors when I took the motor apart as well as the fact that the motor says dc on it.
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Old 07-07-2019, 04:29 AM
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because it's BOTH I bet..
a so called universal motor;

1600Watts is a decent motor for a kart/mini bike btw
And 120Volts isn't really too big of a problem either.
Just get a step up converter and boost say 48V from four batteries to 120V
(heck with a universal motor you could get one of those 120V truck converters and
even reuse the treadmill controller if you get one that'sa ble to provide ~2000-2500 Watts)

But with all bought that would make this motor work,
you spend about as much as you would have spend buying a 1600 or 1800 Boma with matching controller (DC 48V or such)

And it'd give you (not needing a step up converter) a longer ride from the same batteries as well as saving weight.

Sooo yeah it's possible to make it work,
but it's not a good motor to start with really.

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Old 07-07-2019, 05:28 AM
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Awesome guys! Iíll look into everything yíall said and see if I have any more questions.

Thanks all.
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Old 07-07-2019, 05:28 AM
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ERH! Wrong!
It's an AC motor, so unfeasible for a kart.
Unless you feel like having a corded go kart.....
ERH! Wrong!
Treadmills usually use permanent magnet DC motors because a variable speed DC drive is WAY cheaper than a variable frequency AC drive.

I've taken apart probably a dozen over the years for various projects. DC drives and motors.
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Old 07-07-2019, 07:10 AM
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Quote:
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ERH! Wrong!
Treadmills usually use permanent magnet DC motors because a variable speed DC drive is WAY cheaper than a variable frequency AC drive.

I've taken apart probably a dozen over the years for various projects. DC drives and motors.
*Shrug*
It's a device that plugs into the wall, and it's 120V, so I deduced(reasonably) that it was AC.
Ah well, I stand corrected.
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Old 07-07-2019, 08:13 AM
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Just a FYI . Treadmill motors are BDLC motors . Meaning the are brushless dc motors . They do not need 120 volts ac to run. The do need dc and a brushless speed controller with a hall sensor for rotor position to control torque.
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Old 07-07-2019, 09:27 AM
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Just a FYI . Treadmill motors are BDLC motors . Meaning the are brushless dc motors . They do not need 120 volts ac to run. The do need dc and a brushless speed controller with a hall sensor for rotor position to control torque.
That depends on the treadmill. Only the high end gym quality runs run brushless motors. Most of the homeowner ones are just brushed PM DC motors. I have several laying around. I gut discarded treadmills for the speed control and motors and use them to put variable speed on stuff like old benchtop lathes and small drill presses. They work really nicely for that.
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Old 07-07-2019, 09:32 AM
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Itís a permanent magnet dc motor by united technologies automotive. Model #65301. Yíall can look it up and that might clear some stuff up.
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Old 07-07-2019, 10:07 AM
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IM going to chime in here as I used to repair Alternators and electric motors... alot of the other contracts were from a fitness gym chain company....

The machines can be ac, dc, also On some of these big machines.... albeit the input supply was 120vac... The motor itself was 220vac 3ph...... It had to do something from the alternator and transformers, makes it feedback to increase load to user...

So in conclusion.... It depends on the machine.....
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Old 07-08-2019, 11:19 AM
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So... The motor is DC .. 4900 rpm 1.5 HP at 100 VDC ... You will need some reduction... You will also need a lot of voltage . You could over volt the motor but that will create heat and melt it . Controlling the motor is probably the easiest part. You can make a speed controller with mosfets or a variable resistor(Inefficient). I would pass on this motor. You can get a brushless DC motor that can handle constant load at less amps and voltage .
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Old 07-08-2019, 08:01 PM
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Quote:
Originally Posted by bigblkblazin View Post
You can get a brushless DC motor that can handle constant load at less amps and voltage .
No, you cannot.. not a motor you can make use of really anyways
(less amps AND less voltage means a lot less power.. so no )


funny.. around here 100V battery powered lawn mowers become more and more popular..
Aldi just announced a 108V one for next week I think.
Click image for larger version

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Sooo if you can find a batpack for such 100-111 Volt Lawnmower,
chances are it can at least turn the motor over a couple of times;
unfortunately I cannot say anything about the batteries capacity
since it's not stated in the ad.

it's a BLDC and as such comes with a controller as well of course,
but chances are it's nowhere near 1500Watts (I assume something around 500 perhaps)
So the whole package might not move a kart or mini bike too well.
I'd love to try but not for 540 bucks they're asking for it

Anyways a few such batpacks (since they're small) paralleled
to draw enough currents, and you might be able to pull this off.
might not yield impressive milage of course, but hey...
It's certainly a way to make a high voltage motor like yours work
(given you get a matching controller from kellys or such)

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Old 07-14-2019, 11:58 AM
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Is there a battery type/pack that you would suggest? How long could it run for potentially? And what would I have to do to get 2-3 hours of run time in a single go out of it?

Sorry to be a bother, but I do have one more question/statement...

Bear with me please: so with 24Ē diameter wheels, thatís about 6ft per rotation, then if I want to go 20 mph thatís the same as 105,600 rotations per hour or 1,760 rotations per minute, which means if I do 293.3 rotations per minute, thatíll give me 20 mph. (This could all be achieved using sprocket/gear ratios or just running the motor at a lower rpm I think)

So I have a 2hp motor, which I would run at 300 rpm, which would give me like 35 ft-lbs of torque, which could definitely move me+my vehicle considering the 100$ gas motors from Harbor Freight are only 8.1 ft-lbs at 2500rpm...

So all other things aside, would this actually work or is there a glaring mistake in my math that Iím just too dumb to see lmfao

Thanks yíall

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Old 07-14-2019, 07:20 PM
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It REALLY depends on the motor. 35 ft/lb from a 2 HP motor at 350 rpm sounds a bit unlikely to me unless it's got a built in gear reduction.

Your math on the axle rpm sounds right though.
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Old 07-14-2019, 07:24 PM
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The max rpm is supposedly 6000 rpm at 120v and 14ah so with a 20:1 tooth ratio motor:wheel (respectively) that would give me 35 ft-lbs and even if it ends up being half that torque Iíll be happy and the giant bike wheels should mean that I still go pretty fast for a seemingly very slow rpm

Obv my math should be much more conservative than it is because of outside factors and everything that could/will go wrong but all I gotta figure out now is how to run it for 2-3 hours
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Old 07-14-2019, 07:34 PM
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2-3 hrs runtime??

And you're not cruising at slow pace either for that time, huh?
No.. just no!

we're talking 42Ah at the very least (even WITH some cruising) for a 3hr runtime
in a 120V package that'd be 5kWh worth of batpack that's in the realms of 4 thousand dollars
if you buy cheap (that's the size of a small fridge or large'ish radiator in LiPo terms btw)

google "5kWh battery" and take a look at the images you'd be greeted with
so, maybe you want to rethink that idea a tiny bit

24" wheels, huh?
frankly.. in order to even start moving your top speed is not what you should worry about
to calculate gearing, the motor torque is!

really I'm afraid you have so many ideas, that no matter how hard I try,
I cannot seem to see any light at the end of that tunnel...

It's a bad motor to start with and we can deal with that (kindoff),
and now a 3hr runtime on car sized wheels?
Next thing you want is to move two more passengers and a hitch for your camper or something?!

and for gear ratio the last thing you should care about at this point is speed!
You need to massively increase your torque in order to move at all FIRST!
IDK if it can do 20mph... I don't care to do the math for it at this point I'm afraid.

So please forgive me, but I don't think I can help,
You will be massively dissapointed by all reasonable suggestions,
and you are going to buy that predator 212 next month anyways since it comes closest to what you'd really want.

'sid
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Old 07-14-2019, 07:46 PM
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Hahahahahaha lmfao your reaction is great

Youíre so right lmfao. But I have a free motor and so I just wanna mess around with it and be as optimistic as possible. Iím also very new to all this and Iím really not sure how any of this torque and amps and watt stuff works so thatís why Iím relying on yíall. But since itís my first time that why I want to just use this as a learning experience even if it doesnít work. And the only reason I havenít gotten a predator is cuz my parents wonít let me keep gas in the house (I live in a townhouse so no yard/garage/etc) Iím also a sophomore in hs so havenít even had physics yet.

Iím conclusion Iíll keep yíall updated with whatever happens but probs nothing will...

Thanks for everything ✌️

Quick question: why is it not possible to link up say 100 AAA rechargeable NiMH batteries, each has 1.2v and 900mAh so ultimately that would give me 120v and 90Ah... found them on hobby king.

Or

20 lipo packs of 11.1v and 2.2Ah each which would result in higher voltage and the appropriate amount of Ah...

This, along with a controller, seems to work in my primitive mind. Could you explain why this wouldnít in fact work?

Last edited by itsid; 07-15-2019 at 02:57 AM.
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