# Motor to Engine



## onegreenev (May 18, 2012)

Anyone here ever connect an electric motor to an engine? I could use some help. The motor is an AC-35 and I want to couple it to an engine. I don't have access to a CNC machine or even a decent machine shop here where I live. Is there anyone who might be able to help have one built? I have a running VW engine or I can purchase a much more fuel efficient engine if needed. Anyone have an engine to donate? Prefer a diesel if you have one to use bio or veggie oil to operate. I have a welder for building frame work and mounts. 

Pete


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## samwichse (Jan 28, 2012)

Maybe fab a beefier generator mount and place the motor there with a heavy-duty Harley type belt connecting it and cool the engine with a Porschelike shroud and an electric radiator fan?

Only problem with that setup is that you won't be able to run in electric without spinning the gasser.

Is this for a car? Something else?


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## onegreenev (May 18, 2012)

This will be trailer mounted. The car is electric and will be running 96 volts. Need a simple yet strong connection.


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## Duncan (Dec 8, 2008)

Hi Onegreenev

The belt drive idea is a good one,

I have connected generators to motors (AC dyno systems) using a shaft
It's not a trivial problem - you can get in deep dodo with driveline torsionals 

The belt system almost eliminates that issue - go belt


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## onegreenev (May 18, 2012)

I will look into what I might need. Sort of like a wide cogged belt. Motorcycle drive belt? Im most concerned with how to connect up a belt pulley to the engine? Flywheel side?


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## madderscience (Jun 28, 2008)

This must be a genset trailer.

I'm using a toothed industrial belt for the drive on my scion xB conversion.

The big gotchas with a flat toothed belt is that it must be tensioned quite a bit, and also flat belts must be very precisely aligned. They are also somewhat noisy. Though with an engine involved you probably won't notice that. Because a belt is tensioned it puts side loads on the bearings. The motor and/or engine bearings can probably take it, but they may not have originally been designed for it so may wear faster. So far so good with my setup, where the belt goes between an AC55 motor and the pinion flange of a 1984 celica differential.

Unless you are dealing with very high RPM and very high torque, (not the case with a 1238 system or a VW engine) I would suggest that a short drive shaft might be easier to do. The whole thing might not need to much more than a foot long. It should have a couple guibo joints (rubber flex couplings) in it so slight misalignment won't be a problem. Lots of rwd cars use those in their drivetrain like a lot of older BMWs for example. You won't need regular universal joints or a slip coupling since there is no suspension movement, just presumably shock mounted engine and motor to quell vibration a bit. There are lots of drive shaft shops around that could probably make such a thing starting from a couple junkyard shafts and balance it right.


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## Woodsmith (Jun 5, 2008)

I'd go with a short drive shaft too.

Two UJ and a short section of sliding spline from a drive shaft, welded back to back, would do.

I once did one with just two UJs and used the sliding spline on the yoke at the trans end and had a shaft that was, overall, less then 8" long.

Make an adaptor to bolt to the flywheel bolts (obviously you are keeping the flywheel with the ICE) that the UJ flange will mate to, and then do likewise at the motor end.

Allow a little misalignment so that the UJ have to work a bit, that will stop them seizing up.

Alternatively use rubber 'donut' joints.


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## Duncan (Dec 8, 2008)

I will repeat my warning about using a short drive shaft,

You will have two rotational masses with a shaft with some degree of torsional springiness in between,
Then you have an engine giving a cyclic torsional load..

At a certain rpm this WILL destroy itself. (critical speed)
The only question is what is that rpm??

In engine dynos we used a relatively soft driveshaft to move the critical rpm to below idle speed

You could be lucky and end up with a critical speed above your operational range - 
In which case you will be fine,

But be very careful testing it - a driveshaft failure can be frightenning


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## samwichse (Jan 28, 2012)

I probably wouldn't worry too much about side loading the boxer bearings... they're pretty beefy. I'd be more worried about the AC35. If it's not going to be inside the car, chain drive is another option. Less tension required on it. Loud, but you're already looking at an aircooled VW engine, so who cares? 

I'd probably go with something more modern and fuel efficient unless you're really tied to the VW. Even if you upgrade to FI with something like a megasquirt, they just aren't that efficient.

A 3 cylinder, water cooled engine from a Honda Insight weighs about the same all-in with the same or better output (peak 66hp). If you're doing AC anyway, it's got a generator built in you could probably pull 15-20kw continuous from with cooling. Or pull that and drive your AC35.








A Toy or Honda 1.5-1.6L are plentiful but a bit heavier and probably power overkill for what you need. Still way better efficiency than your VW.


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## onegreenev (May 18, 2012)

Yes, I am very aware of the crappy fuel mileage of the old VW. Lets see, Yes, Ive been working with VW's since 1974. This is mostly for testing. The insight sounds good but the generator is controlled by the insight inverter. Not by a Curtis inverter. Not the same voltage either. Now, using a much more efficient engine will be in order. But it makes it much more complex as you get into fuel injection and turbo charged and such with the needed computers to operate them. Its not what Im after. Id prefer a diesel and use veggie oil to power it. Carbon Neutral. 

Seems odd that you can use a drive shaft with your car but not an engine and motor? I can use a drive shaft with a boat too. But not coupled to a motor? Sounds quite odd to me. I use a drive shaft coupled to my tractor implements too. Mmmmm. You know, Im not looking to spin this sucker at 10000 rpm. Maybe 2500. Yes it will need to be well balanced. Not just a tossed together thing.


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## onegreenev (May 18, 2012)

Im actually just wanting help to build it. If my ideas are not sound so be it but I still need help building it. What I don't need is a bunch of help on how its not a good idea. Its going to be built with or without help from here. Just thought Id ask if anyone is interested in helping make it happen. Once done and shown to work then refining the beast will follow. 

Any takers?


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## z_power (Dec 17, 2011)

How about positionig both motor and engine shafts in one line as precisely as you can and then using lovejoy coupler? With polyurethane "spider" this coupler can compensate small imperfections, is lightweight and relatively safe (anyway I'd use sheetmetal cover around exposed rotating parts - just in case...) Manufacturers of couplers do supply all tech data with max. torque, pulsation and rpm specs so you can design it in engineer's fashion


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## onegreenev (May 18, 2012)

That would work for a short term and will be acceptable but how to connect the lovejoy to the engine. Connecting to the motor is not the huge issue. Are there couplers that bolt directly to the flywheel or end of the crank? I have been thinking of some sort of adaptor that will bolt directly to the flywheel where the pressure plate would bolt up to then the center portion just connect directly to the motors shaft.


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## z_power (Dec 17, 2011)

What kind of flywheel mount is there in your engine; one center bolt/nut or a few bolts on circular pattern? In second case adapter could be fabricated with evem small lathe - think about collar mounted with longer bolts on top of flywheel and then smaller dia. stub for lovejoy (i'm not good at drawings so this will remain verbal only).


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## samwichse (Jan 28, 2012)

onegreenev said:


> What I don't need is a bunch of help on how its not a good idea. Its going to be built with or without help from here. Just thought Id ask if anyone is interested in helping make it happen. Once done and shown to work then refining the beast will follow.


Sorry, thought I was helping. Didn't know you already had a specific inverter in mind.


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## Duncan (Dec 8, 2008)

onegreenev said:


> Seems odd that you can use a drive shaft with your car but not an engine and motor? I can use a drive shaft with a boat too. But not coupled to a motor? Sounds quite odd to me. I use a drive shaft coupled to my tractor implements too. Mmmmm. You know, Im not looking to spin this sucker at 10000 rpm. Maybe 2500. Yes it will need to be well balanced. Not just a tossed together thing.


Its down to the rotational inertia - you have a mass on each end of the spring 

The boat has very little rotational inertia in the prop - 

The tractor and car drive use gearboxes - which kind of remove the resonance

You may well get away with it - just don't lean over the driveshaft when you are testing it

Personally I would use a belt drive - simple, easy,


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## onegreenev (May 18, 2012)

samwichse said:


> Sorry, thought I was helping. Didn't know you already had a specific inverter in mind.


No problem. Usually AC motors are matched to the inverter. For ease of use I plan on using the Curtis controller with the AC-35 motor for initial testing since my building of the inverter kit is at a stand still for now. I need to be able to sit for longer periods without having my foot up. Had surgery and now in recovery. Later I hope to use my forklift AC motor and DIY controller to do the same thing. If not I plan on using the forklift motor and diy controller to do outboard motor setups. If the DIY controller works the price point will be well in the reach of everyone. Not just some.


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## reubenT (Jun 17, 2009)

done that kind of thing several times. It's best to have a metal lathe available. Belt drive can be done but motor/generator would need pretty heavy shaft and good size bearing to handle side loading. Takes at least 3 B belts, preferably 4 to handle power from a 75-100 hp engine. I matched pulley to flywheel by cutting a shallow shelf in the flywheel on a lathe to set the pulley into, then drilling and tapping holes and bolting pulley to flywheel. belts and pulleys from surplus center Lincoln, NE are much cheaper than most industrial suppliers.

If no increase from engine speed is OK, Might be better to use a flex coupler, like that used between engines and hydraulic pumps. "Lovejoy" is one common brand. Ive done that by bolting a round steel plate to back of lovejoy coupler and then bolting that plate to the flywheel, carefully centered, Used to do it without a lathe but precise centering was difficult. Much better to turn the plate out on a lathe to fit both sides. The rubber star can handle a tiny bit of misalignment but not much.

If yer doing much in the line of nonstandard assembly a lathe is an awfully good investment. I found a good old one for $400 a few years ago. although i had to drive a ways to get it.


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## nimblemotors (Oct 1, 2010)

Use the engine clutch, and take a transmission input shaft and weld on the motor shaft coupler.
The clutch discs have those springs in them, which btw, I've noticed with my Boxster, they don't use the springs
and have a solid clutch disc, which a certain EV racer said would destroy a transmission, so much for that.


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## dragonsgate (May 19, 2012)

Off hand I think a belt drive would be the easiest way to go. How about some pictures of the two ends you are trying to join.


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## onegreenev (May 18, 2012)

dragonsgate said:


> Off hand I think a belt drive would be the easiest way to go. How about some pictures of the two ends you are trying to join.



The below picture is of an old VW engine and I have figured that using the fan pulley end will be the easiest. The serpentine belt setup with a longer belt may be best. Then I only have to make up a simple but strong adjustable mount for them both. 

AC motor right now is my Forklift AC motor or my AC-35 which is the standard size shaft for our DC motors with a key. 

Pete


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## samwichse (Jan 28, 2012)

What will you do for cooling on the VW? Electric fan?

At least your controller will give you a built-in beastly starter.

For stationary, I would recommend a larger oil reservoir/cooler if you can.


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## onegreenev (May 18, 2012)

I can still utilize the stock cooling fan. It runs off the generator which runs off the front crank pulley. I'll just set it up to also run the AC motor from the crank pulley. Just leave the flywheel on for engine balance


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