# transmission less conversion



## Frankenfiftyfour (Jul 22, 2019)

Hi

Has anyone done a motor direct connect to driveshaft conversion? What adapters or solutions did you come up with, or anyone know of any examples? I need to go directly from the motor to the driveshaft. Any help be appreciated.

Thanks


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## Duncan (Dec 8, 2008)

Assuming that you mean from the motor to the propshaft - that is the way my "Device" works 
It means that you can put the motor where the gearbox would live

https://www.diyelectriccar.com/foru...dubious-device-44370p15.html?highlight=duncan

Mine was dead easy the Hitachi motor had a brake on one end - I snaffled the female spline drive and made a simple disc adapter to the prop shaft


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## Frankenfiftyfour (Jul 22, 2019)

Cool build Duncan,

What im looking to do is mount the electric motor up front in engine bay area where the old gas engine and transmission lived. Connecting it to the original drive shaft to the original diff in the rear. Im looking for ideas on how to mate the electric motor shaft to the yoke on the drive shaft.


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## Duncan (Dec 8, 2008)

Yes - that is effectively what I did - but the motor takes the place of the transmission - leaving the whole "engine bay" for batteries

The adapter is a simple disc with holes tapped at 8mm and a machined ring on each side to keep the two parts concentric


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## Frankenfiftyfour (Jul 22, 2019)

Yes, that's what I need except I have keyed shaft on my motor. I need to figure out how to go from that to a yoke at the other end. 

How did you do reverse?


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## Duncan (Dec 8, 2008)

Reverse is easy - just use a reversing contactor 

I used one off an old forklift - a small 24v one - but I did oveload it at the last drag races so I bought a bigger one

You will need need an adapter for your shaft - I'm NOT in favout of driving through the key you will need the taper lock type of adaptor 

https://www.youtube.com/watch?v=fT4axK3haQ0

Next 
the drive shaft - a two UJ type shaft needs to have some end movement - some axial movement
My car has that with movement of the female spline part on the male spline 

Any type of clamping lock on a keyed driveshaft will NOT have any axial movement - so you will need the axial movement in the propshaft

A lot of (most?) car propshafts do have an axial sliding joint as part of the propshaft


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## Frankenfiftyfour (Jul 22, 2019)

So the taper lock joint would take the place of a splined slip yoke to provide axial movement?


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## Duncan (Dec 8, 2008)

Frankenfiftyfour said:


> So the taper lock joint would take the place of a splined slip yoke to provide axial movement?


No - the taper lock would have zero movement - but most propshafts have a sliding joint as part of the propshaft


https://bearmach.com/propshaft-br-0404

The propshaft on this page has a sliding joint 

Some propshafts don't have a sliding joint because the gearbox output has it built in


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## Frankenfiftyfour (Jul 22, 2019)

My brain hurts now...lol...So the original transmission had a male splined shaft and the drive shaft had a female splined piece that fit into it...This is a 54 Ford...So Im having issues of how to mate this key shaft electric motor into it...This is my first attempt into doing an electric conversion and trying to figure out to combine the modern to the old


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## Duncan (Dec 8, 2008)

OK first treat the propshaft as "parts"

The diff end will be a flange with four bolts

You need to get hold of another propshaft so that you have got the splined bit and both ends
That page I linked to was for landrovers (I think) but all sorts of machinery from the 50's to the 80's had propshafts and I'm pretty sure there are only a couple of sizes

Then forget about that bit until you have the adapter on your driveshaft and the motor bolted into the car

Now you need to measure how long a propshaft you need and take all your bits and that measurement to a local machine shop - they will cut and weld you a new propshaft

Here (NZ) I needed to get it balanced and to have some metal around it in case it broke


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## brian_ (Feb 7, 2017)

Frankenfiftyfour said:


> My brain hurts now...lol...So the original transmission had a male splined shaft and the drive shaft had a female splined piece that fit into it...This is a 54 Ford...So Im having issues of how to mate this key shaft electric motor into it...This is my first attempt into doing an electric conversion and trying to figure out to combine the modern to the old


The female splined end of the original 1954 Ford prop shaft was probably free to slide on the male splined end of the transmission's output shaft. Since your motor does not have a splined shaft, you can
- use something like the TransWarP setup (splined shaft and bearing in a housing), or 
- just attach a splined end to the motor shaft (probably not structurally sound), or
- attach a U-joint yoke to the motor and use a shaft which has a sliding section in it (the ability to slide is called "plunge").

There are a lot more than two standard sizes of propeller shaft components, and few modern cars have a sliding (plunging) feature in a propeller shaft. Fortunately companies which specialize in supplying these components and fabricating shafts to connect the parts that you have, often with "driveline" in their names.


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## Frankenfiftyfour (Jul 22, 2019)

So, What about if I got a coupler that mated the keyed shaft on one side and a six inch section of the output shaft from the original transmission? This would be able to slip into the original driveshaft. Would it be an issue strength wise being this length? Also, would it be an issue of the output shaft being in the slip yoke without the collar that was on the transmission tail piece?


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## Duncan (Dec 8, 2008)

Frankenfiftyfour said:


> So, What about if I got a coupler that mated the keyed shaft on one side and a six inch section of the output shaft from the original transmission? This would be able to slip into the original driveshaft. Would it be an issue strength wise being this length? Also, would it be an issue of the output shaft being in the slip yoke without the collar that was on the transmission tail piece?


Your problem with that is ensuring that it was well enough mounted to the motor driveshaft - it would need to be very rigid to avoid it whipping 

I would prefer the driveshaft with the "plunging" joint in it -


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## Frankenfiftyfour (Jul 22, 2019)

Could you show me an example of this type of drive shaft? Im not familiar with this.


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## Frankenfiftyfour (Jul 22, 2019)

This is the one part of the build I am stumbled with


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## Duncan (Dec 8, 2008)

The page I linked to had an example 

https://bearmach.com/propshaft-br-0404

That one is for a landrover


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## Frankenfiftyfour (Jul 22, 2019)

Ok, so there is travel in the middle. So this is a full drive shaft or a segment piece to complete the length from my motor to the existing drive shaft. Please bear with me if Im asking stupid questions, this is the area of the build I'm confused with


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## Duncan (Dec 8, 2008)

OK that's an example - you may be able to just buy one the right length - or move your motor back or forwards until the length works out

Otherwise you would get a machine shop to cut and weld - you can see both ends of my driveshaft in the last picture - it's only about a foot long

Using an "off the shelf" one has a lot of advantages

In your shoes I would - 
first look at your transmission tunnel -
is it large enough for your motor? 
- can you make it large enough?
That sets where the motor can live

take your existing propshaft and offer it up - that will show how long a shaft you need and what size UJ you need to go onto the diff

Then go to your parts supplier and talk to him 
Most older cars had propshafts, today BMW and Subaru and various trucks have propshafts

Find what there is - if you are lucky you can buy a new one or get one from a scrapyard

Don't forget the space needed for the adapter that goes on the drive shaft


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## brian_ (Feb 7, 2017)

Frankenfiftyfour said:


> So, What about if I got a coupler that mated the keyed shaft on one side and a six inch section of the output shaft from the original transmission? This would be able to slip into the original driveshaft. Would it be an issue strength wise being this length?





Duncan said:


> Your problem with that is ensuring that it was well enough mounted to the motor driveshaft - it would need to be very rigid to avoid it whipping
> 
> I would prefer the driveshaft with the "plunging" joint in it -


I agree with Duncan. That's why I listed this alternative as "probably not structurally sound" earlier.



Frankenfiftyfour said:


> Also, would it be an issue of the output shaft being in the slip yoke without the collar that was on the transmission tail piece?


The usual tailshaft housing surrounds the sliding bit of female splined shaft, as a protective cover; the equivalent sliding section in a shaft typically has a rubber boot. Yes, protecting the sliding section from getting dirt in it is an issue.



Frankenfiftyfour said:


> So this is a full drive shaft or a segment piece to complete the length from my motor to the existing drive shaft.





Duncan said:


> ... you may be able to just buy one the right length - or move your motor back or forwards until the length works out


Many long trucks have multi-part propeller shafts, with a joint and steady bearing and support bracket at each connection between shafts. This shouldn't be necessary in a car, especially if you can put the motor back in the transmission tunnel, but many current cars do use two-part prop shafts.



Duncan said:


> Using an "off the shelf" one has a lot of advantages
> ...
> Most older cars had propshafts, today BMW and Subaru and various trucks have propshafts
> 
> ...


Anything with an engine and transmission in the front, and driven rear wheels, will have a propeller shaft (so yes, almost all BMWs and pickup trucks are examples); however, many won't have a sliding part of the shaft, either because they use a sliding spline at the transmission output shaft (like the '54 Ford), or because they use constant velocity joints (instead of U-joints) which allow plunge, just like the axle shafts used with independent suspensions.

A live beam axle (such as in this 1954 Ford) will typically require more shaft length change than an independent rear suspension (in which the final drive unit basically stays stationary). With IRS, the shaft might even get away with the slight length change allowed by guibo couplings, but you wouldn't want to depend on that with a beam axle.

In a quick search, it does appear that BMW tends to use shafts with a sliding section. Here in Canada it's hard to imagine a more expensive source of parts than German luxury-performance auto manufacturers, but of course this varies by location.

All-wheel-drive vehicles will have a propeller shaft (except for electric vehicles, and hybrid vehicles with electric-only drive to the axle at the other end from the engine); however, that shaft may not be designed to handle a lot of power.


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## Frankenfiftyfour (Jul 22, 2019)

Heres what Im looking at to mate, I am mounting motor in transmission tunnel but it leaves a gap of 10 inches from end of slip yoke and the face of the motor


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## Duncan (Dec 8, 2008)

Hi 
I would throw that coupling away - the very way it works guarantees that it will not be concentric

Can you shift the motor back the ten inches? - Shorter propshafts are better - if you have to do some metalwork expanding the transmission tunnel that is better than messing with the propshaft

You need a proper coupling the type that uses a conical thing to clamp onto your motor driveshaft


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## Frankenfiftyfour (Jul 22, 2019)

I guess I could, would I still need a new driveshaft? I could even move the motor mid ship and hook into the diff. But, in any of these configurations I would need a slip drive shaft of some sort, correct?


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## Duncan (Dec 8, 2008)

Frankenfiftyfour said:


> I guess I could, would I still need a new driveshaft? I could even move the motor mid ship and hook into the diff. But, in any of these configurations I would need a slip drive shaft of some sort, correct?


 Yes - you still need a slip/plunge joint - 
change the order of events - 
if you can move the motor then take your propshaft to your handy local scrapyard or other supplier and have a look at what he has 

Then go back to the motor position - rinse and repeat until you have got it sorted

A new propshaft is not that expensive - could be best to bite the bullet and get a new one


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## remy_martian (Feb 4, 2019)

A couple of other ideas (recognizing this is a '54 Ford):

1) Mount the motor on the rear carrier, no driveshaft or slip joint, still need a coupler if you don't use a chain or belt drive, or

2) Put an IRS in the back (many hotrodders, nowadays, known as "restomodders", do anyway, which again eliminates the slip joint, needs a coupler and an arbitrarily long driveshaft. Unlike the old days where Corvette and Jag were the only readily available choices, there are a few more out there for IRS these days.

One other issue you need to think about with your industrial motor (seems to be a secret of what it is with the way you took the pics, so I have to guess that's what it might be given the keyed shaft) is cooling.

Most stationary motors have an integral fan on the rotor, which is completely useless at low RPM, and that's where most people dump the highest current into a traction motor. You can get some motors that have a separately motored fan from things like machine tools (not cheap).

Maybe you have that taken care of, but getting gobs of air down a trans tunnel that's plugged by a motor is a tough nut to crack as well. Especially fun when you have a block of batteries blocking airflow to the tunnel.

You also are starting out with a heavy car. Coupling it to the rear end by whatever means only gives you a 3:1 to 5:1 torque increase. If you're using a 3600 RPM motor, you don't have much choice but to couple to the rear end if you want to have a chance at hitting highway speeds, If it fits in a tunnel, with direct drive acceleration could be sucky, though.

I'm sure you've done the math on wheel speed. Less likely you did the math for acceleration. Putting the motor anywhere, including the engine bay, needs thinking about cooling and not merely about how to attach the rotor to a prop shaft.

As I said, maybe you've thought about all this, but if you (or future project folks) haven't, you may be in for a nasty & expensive surprise.


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## Frankenfiftyfour (Jul 22, 2019)

Interesting info. I am still in the early stages of this project so am open to all possibilities. The car had an automatic transmission so i'm in search of a manual swap. But they are pricey. 

It is a heavier car but the car is being placed on an extreme diet and hope to get it down to 2200-2500 pounds. 

Now mounting it in the rear is an interesting idea. What is it you mean to mount it to the rear carrier? 

I can someway get air to the motor, the car had fresh air inlets at front grill that I can use ducting to get air anywhere, but that would only help at higher speeds. 

So, I am looking for ideas, any info at all would help me greatly


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## remy_martian (Feb 4, 2019)

A differential carrier mounted traction motor is really crappy for unsprung weight, but if you're driving a land yacht or truck it doesn't matter a whole lot and it does completely free up tunnels and the volume between the frame rails. 

It's used a lot on golf carts and on some medium-heavy electric trucks like the Wrightspeed. 

Here's an engineered solution to get you brainstorming: https://www.trucknews.com/products/workhorse-using-dana-axle/

Lots of possibilities. All you need is time & money.


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## rob_kr (Apr 8, 2016)

On my project (59 Cadillac) I used a TorqueBox 2:1 gear reduction unit. The optimal efficiency of the tandem motors (Siemens Azure) is around 6000 rpm, and with the gear-ratio of the differential, the wheel-size etc that'd be just north of 150 mph. With the TorqueBox installed it should be around 75-78 mph, pretty much the cruising speed on my commute.

The output shaft of the TorqueBox has a yoke that fits the U-joints/bearings of the original drive shaft, and it has the splined input & adapter plate to mate to the motors. Not the cheapest way to go, but an elegant solution for sure.


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## Frankenfiftyfour (Jul 22, 2019)

Whoaa...they are pretty expensive...just looked at them


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## lawrencerhodes (Mar 31, 2008)

John Wayland did this decades ago using two motors. You should upgrade as your car weighs twice what White Zombie does. http://electricandhybridcars.com/index.php/pages/worldsfastestcar.html This is an old link. You may google to find something newer but since this page was made the car was reinforced due to all the wheelies. New lithium pack. Involved in a crash on a TV show.


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## rob_kr (Apr 8, 2016)

For a 54 Ford (say a Customliner sedan) you do need 2x something. 

In this case, I think you can make it work with 1 motor and a 2x gear reduction. The gear reduction will halve your rpm (so now the 6000 rpm from the motor fit the 3000-rpm drive train design) and it will double your torque. That should get the total weight off the line with normal-people performance.

If you want white-zombie-speeds etc then yes, the whole car needs to be reinforced etc.

I'm doing a 1959 Cadillac sedan, and it's with 2 motors and a 2x reduction. A Karman Ghia is 1800 lbs and uses 1 motor & no gear because the drive train needs 4000-6000 rpm, the Ford Customliner at 3500 lbs would use 1 motor and a 2x reduction, and the Cadillac is 5600 lbs with 2 motors and a 2x reduction. 

There's a weird logic in those numbers but I think it all works out....


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## Duncan (Dec 8, 2008)

You only want the reduction gear if you are using a wimpy AC motor

A DC motor is a LOT cheaper 
Does not need the reduction gear
And you probably don't need two

But it is a little less "sophisticated"


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## Frankenfiftyfour (Jul 22, 2019)

Here's an idea I was thinking about. I still have the output housing and shaft from the transmission. If I could modify it to mount to the electric motor and it would solve a lot of problems. Here's the issue with that:

The original set up fed ATF to keep the output shaft for lubrication.

What if I tapped the housing for grease fittings to pump grease into the areas in question? Would this even work?


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## remy_martian (Feb 4, 2019)

The output shaft spins on a bronze bearing. If you seal the front of the tailshaft housing with your adapter plate, you might be able to get away with simply filling the tailshaft housing with ATF. The trans I rebuilt last summer actually used the tailshaft housing as an ATF reservoir in addition to the pan. Alignment of the motor/shaft and that rear bearing will be interesting.


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## Duncan (Dec 8, 2008)

Frankenfiftyfour said:


> Here's an idea I was thinking about. I still have the output housing and shaft from the transmission. If I could modify it to mount to the electric motor and it would solve a lot of problems. Here's the issue with that:
> 
> The original set up fed ATF to keep the output shaft for lubrication.
> 
> What if I tapped the housing for grease fittings to pump grease into the areas in question? Would this even work?


That sounds to me to be VERY VERY DIFFICULT - and with no advantages


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## lawrencerhodes (Mar 31, 2008)

Maybe find a drive shaft from a manual vehivle.. Or find a transmission to mount in the vehicle. Lots easier to use two motors. Makes a peppy ride that can be quite bullet proof.


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## brian_ (Feb 7, 2017)

Duncan said:


> You only want the reduction gear if you are using a wimpy AC motor
> 
> A DC motor is a LOT cheaper
> Does not need the reduction gear...


Yeah, Tesla's motors must be really wimpy, since they seem to need that 12:1 ratio two-stage reduction. 

You can productively use a greater reduction ratio than existing in the final drive if your motor can turn more than a few thousand rpm. If you're using century-old technology with brushes that don't let the motor turn as fast as an economy car's engine, then you use a really big motor at low speed, and the stock final drive ratio works well.

In looking at alternatives for my Spitfire, I concluded that if I were to convert it, I would want to keep the existing final drive and to eliminate any other transmission (so it would be configured like the plan for this project). I have considered the Chevrolet Spark EV motor, because it was designed to be used with only one stage of reduction gearing... and while it is built with the same technology as the Chevrolet Bolt motor, the slower Spark EV motor is substantially bigger and heavier while capable of producing less power. That's the price of slow motor operation, but if your type of motor can only turn slowly, then maybe that's not a problem.


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## brian_ (Feb 7, 2017)

Frankenfiftyfour said:


> Here's an idea I was thinking about. I still have the output housing and shaft from the transmission. If I could modify it to mount to the electric motor and it would solve a lot of problems. Here's the issue with that:
> 
> The original set up fed ATF to keep the output shaft for lubrication.
> 
> What if I tapped the housing for grease fittings to pump grease into the areas in question? Would this even work?


What you are talking about doing is essentially duplicating NetGain's TransWarP motors, which are the same as their WarP motors (which are generic brushed series DC motors like those from an old forklift), but with a splined shaft end and added tailshaft housing. For lubrication, they only add grease fittings for the slip joint... but the output spline is on the motor shaft, so they're not adding or needing to support an extra shaft section, and larger sizes (9" and 11") have upgraded output-end bearings to handle the radial load.

If you must use a common motor without a splined output compatible with a sliding yoke for the propeller shaft, and your motor speed doesn't call for additional reduction gearing, a simple U-joint yoke and a propeller shaft with a sliding section (as Duncan suggested) is certainly the straightforward solution.


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## rob_kr (Apr 8, 2016)

Duncan said:


> You only want the reduction gear if you are using a wimpy AC motor
> 
> A DC motor is a LOT cheaper
> Does not need the reduction gear
> ...


AC or DC is hardly the point. Also, I just looked and a 70 bhp AC motor is $2,900 and a 58 bhp DC motor (warp 11) is $3,200. Close enough that no-one is a LOT cheaper.

My point/question (because of the type of the cars) was about total bhp and total torque. I'll happily take any advice I can get, I'm not interested in measuring wimpiness or sophistication. This is an engineering puzzle so let's stick to the numbers.

I'm trying to match driving behavior. Like accelerating from 65 to 80 mph to over-take Elmer Fudd in his pick-up truck. For that, things should be close to original (I think).

The original engine had 430 ft lbs of torque and 325 bhp @ 51% rating (at 4,000 rpm). Alright, so be it, and those are the numbers I need to match to get to comparable performance. 

One DC Warp 11 is ~55kW, so two of them is 110 kW / 0.7 = 160 bhp. The original had 51% of 325 = 170 bhp at the drive shaft, so I'm pretty close (within 10%). 

One DC Warp 11 has 140 ft lbs. I need 430, so 3x what one Warp 11 can do. So, take 2 Warp 11's and a helical gear = 2 x 140 x 1.7 = 475 ft lbs. Again, a little better, but not a lot (10%).

Sure, I should get all my torque at 0 rpm / start-up and all that, but I'm building a road-car, not a drag racer. To me the numbers say 2 motors and a gear. If there's a hole in these numbers then let's discuss. What am I missing in this?

Yes, I went with AC because of what I had available, and my motors actually get about 100 bhp and 200+ ft lbs each so I should have a zippier car than what it was originally. Then again, the original was hardly a street racer plus this is the US so it's not going to help with speed-limits of 65 and 70 mph ...


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## kennybobby (Aug 10, 2012)

@rob

do you have a gearbox and differential? don't forget about the torque multiplication of those gears.


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## Duncan (Dec 8, 2008)

Hi Rob kr

I paid $100(NZ) form my first Hitachi 11 inch motor

The latest one I bought (as a spare) cost me $200 

THAT is the cost of DC motors - and I'm pushing 1200 amps and 340 volts - 500 hp

You are comparing that to a limp wristed 70 hp at 15 times the cost!

AND the AC motor will need a controller that is a lot more expensive than a P&S 

Modern OEM AC motors are GREAT

Aftermarket AC motors are wimpy and expensive


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## Frank (Dec 6, 2008)

I don't know where you got your Warp 11 numbers but they don't make sense... nothing beats good old - fashioned DC series for torque! How many apps to get that number? 

Sent from my SM-T380 using Tapatalk


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## rob_kr (Apr 8, 2016)

kennybobby said:


> @rob
> 
> do you have a gearbox and differential? don't forget about the torque multiplication of those gears.


I don't use the original gearbox because that's what creates up roughly half the loss in rated horse-power in the original setup plus it's an awkward thing to convert into. It would need add'l hydraulic plumbing, a modulated vacuum line, a kick-down <something>, a lot of parts & pieces.

In 3rd gear the original gear-box becomes a flat 1:1, so no more multiplier. That's how I figured the matching, at 65 mph (say) so as minimal-reduction as it gets. When pulling away the engine never got much above 1/2-2/3 of max, and per the engine rpm<>ft.lbs curve it still works out OK, but that part (losing the add'l multiplier of 1st gear) is a worry until it all proves out.

I do still use the original differential, but it's a same-same i.e. that was there on the original too, so for the direct engine<>motor matching exercise I ignored it.


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## rob_kr (Apr 8, 2016)

Frank said:


> I don't know where you got your Warp 11 numbers but they don't make sense... nothing beats good old - fashioned DC series for torque! How many apps to get that number?
> 
> Sent from my SM-T380 using Tapatalk


I use the numbers from www.EVwest.com and a couple others like it. The guys at EVwest have been solid so far but it could all be totally wrong, I have no way of telling? 

Their web-site quotes the Warp-11 as (and I'm copy-pasting here):
Rated Torque: 173 Lb Ft @ 72 Volts And 597 Amps (1442 RPM) 
Rated Power: 58 HP @ @ 72 Volts And 597 Amps (1442 RPM) 
The volt/amp > HP math is right, so I'm trusting the ft/lbs number?

By comparison, they quote the AC azure motor as have bench tested to 160HP and 221 ft lbs of torque at 300V and 400A.. Same thing, the Volt/Amp > bhp math is right, and it looks right?

All in all, this (to me) said I'd get way better bhp but lower torque per kW going with the Azures vd the Warp-11's. The reduction gear makes up for the torque "loss", so as a package it sounded OK. The weight of the car says I do need the bhp (at 65 mph) and I have the extra torque covered, so it all seemed to line up? On paper anyway? I guess I'll find out.


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## rob_kr (Apr 8, 2016)

@Duncan:

Sure, I have wimpy motors, and maybe I just got things backwards. I can still flip to something else (I can always Ebay the parts and come out even/ahead), so I'll ask:

- what's the model of the Hitachi motor(s)? I can't find one that is more than maybe 15-20 kW at 3000+ rpm between Ebay, Craigslist etc without getting some humongous grey dead-weight. I can call the local Hitachi dealer but for that a part-number would seriously help...

- what's the car? 

I'm asking because I am stuck figuring out my cooling and with your Amp & Voltage numbers you're a ways ahead of me. 

My battery is 340V and 100 kWh, but I won't know the running amps until I get this thing to 65 mph. What do you see for amps going up-hill & down-hill at say 65 mph, and what kind of setup do you run to keep it all from overheating? Do you cool the batteries? The controller? The motor? Where is the majority of the heat coming from? 

I know, it's a lot of questions, but it sounds like you've figured stuff out I haven't yet...


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## brian_ (Feb 7, 2017)

rob_kr said:


> AC or DC is hardly the point. Also, I just looked and a 70 bhp AC motor is $2,900 and a 58 bhp DC motor (warp 11) is $3,200. Close enough that no-one is a LOT cheaper.


The idea that DC is much cheaper is based primarily on the assumption that DC means a salvaged motor such as from a forklift, while an AC motor will be new. There is also a likely difference in controller cost, since a DC controller is simpler than an inverter. This sort of generalization is useless and confusing.


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## brian_ (Feb 7, 2017)

Duncan said:


> Aftermarket AC motors are wimpy and expensive


Low-voltage aftermarket AC motors for industrial equipment, sold to DIY EV converters, are relatively wimpy and expensive. High-performance high-voltage AC motors (such as the BorgWarner and YASA products) are available and comparable to OEM motors, but very expensive. Overly broad categories don't help, and cause confusion.


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## brian_ (Feb 7, 2017)

rob_kr said:


> @- what's the model of the Hitachi motor(s)? I can't find one that is more than maybe 15-20 kW at 3000+ rpm between Ebay, Craigslist etc without getting some humongous grey dead-weight. I can call the local Hitachi dealer but for that a part-number would seriously help..


If you're going with the "cheap DC" approach, forget model numbers. The general method appears to be to find someone scrapping forklifts, and buy the biggest rotating hunk of iron and copper you can find. It is then operated at much higher voltage and current than intended, so nothing about the original ratings apply and manufacturers specs don't tell you much.


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## Frankenfiftyfour (Jul 22, 2019)

So i'm thinking either doing the Transwarp tail housing or doing the sliding driveshaft. I'm not even sure they sell the tail house separately


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## brian_ (Feb 7, 2017)

Even if NetGain sold the housing separately, it wouldn't do you any good if your motor doesn't have the same extended shaft with splined end as a TransWarP motor.


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## MattsAwesomeStuff (Aug 10, 2017)

brian_ said:


> Low-voltage aftermarket AC motors for industrial equipment, sold to DIY EV converters, are relatively wimpy and expensive.


I can't really ever get a solid answer about why that is.

Yeah, if you run them at rated voltage, they'll be wimpy. But so are DC forklift motors until you overvolt them.

What's the difference between an overvolted AC motor and something more purpose built for EV use? I can't think of many differences, even fewer than on DC motors.


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## Duncan (Dec 8, 2008)

Hi rob kr

This is my car
https://www.diyelectriccar.com/foru...dubious-device-44370p15.html?highlight=duncan

Not at all sure it's an example of what to do but it is great fun

Matt
The problem is that a DC motor controller is easy and you can very simply over amp and over volt them

AC motor controllers are much much more difficult and you can't just slap something together and go


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## MattsAwesomeStuff (Aug 10, 2017)

> The problem is that a DC motor controller is easy and you can very simply over amp and over volt them
> 
> AC motor controllers are much much more difficult and you can't just slap something together and go


Other than the difficulty of tuning your parameters... any reason I shouldn't be able to pull as much power from an AC?

Like, I think about my 265 lb AC forklift motor, and compare it to what's in a Tesla (which has a gearbox added to it), and the Tesla large rear motor is like, 15-20x the power, for 1/3 the weight (before gearbox and inverter). That's... 45-60x as power dense.

So, other than just adding more voltage than it was designed for, and maybe spinning it faster than it was designed for, can it be comparable?


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## Duncan (Dec 8, 2008)

Hi Matt

Two engineers - Tesla and Forklift
The Tesla guy has low weight and power as absolute goals

The Forklift guy does NOT
If he designs a light motor then they need more weights and people will look at it and snear 
Same with power 

Saying that I AM getting a LOT more power out of my Hitachi motor - but I don't expect to get 200,000 miles out of it


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## Eddie49 (Dec 6, 2018)

MattsAwesomeStuff said:


> What's the difference between an overvolted AC motor and something more purpose built for EV use? I can't think of many differences, even fewer than on DC motors.


One difference that seems to be fairly common is that, if they have any cooling at all, industrial AC motors are cooled by a fan on the motor shaft, whereas high-performance AC motors that are purpose-built for use in EVs are fluid-cooled.


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## kennybobby (Aug 10, 2012)

*Industrial AC motor notes*

Most industrial AC motors (3-phase, ~480vac, 50 or 60Hz) are wound with lots of turns of small gage wire in the necessary pole pattern to achieve the desired speed of operation e.g. 3600, 1800, 1200 for 2,4,6 pole motors. This provides an inductance and resistance that can handle the frequency and currents associated with the 480vac supply voltage. Note that this winding will have a quite high back emf (voltage generated by the rotor in motion) also.

In order to operate one of these from a DC power source would require about 680 VDC just to match the performance as if running from the AC mains. That is way higher than anybody's pack voltage and only gets you to 3600 rpm max for a 2-pole motor. There is no over-volting such an AC motor to run faster--adding more voltage does not get you higher rpm, even if you could build a pack above 680 VDC.

To get the torque and speed needed for EVs requires a different winding with a pole count and inductance suitable for the frequency range, and with a wire gage that can handle the current at a lower supply voltage typical of EVs, e.g. OEMs ~360-400VDC. Then you need a controller or motor inverter than can produce 3-phase currents at much higher than 60 Hz.


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## brian_ (Feb 7, 2017)

*Re: Industrial AC motor notes*



kennybobby said:


> Most industrial AC motors (3-phase, ~480vac, 50 or 60Hz) are wound with lots of turns of small gage wire in the necessary pole pattern to achieve the desired speed of operation e.g. 3600, 1800, 1200 for 2,4,6 pole motors.
> ...
> In order to operate one of these from a DC power source would require about 680 VDC just to match the performance as if running from the AC mains. That is way higher than anybody's pack voltage and only gets you to 3600 rpm max for a 2-pole motor.


I don't think the question which Matt raised was about pushing a 480 VAC industrial motor. The discussion was comparing brushed DC motors (which can be pushed from their 48 V ratings in forklifts and up to 120 V ratings as aftermarket items) to similarly sized induction motors (can they be pushed from their up to 120 V ratings?)

An EV running typical production voltage (360 V, nominally) can drive these motors at much higher than 120 VAC.



kennybobby said:


> There is no over-volting such an AC motor to run faster--adding more voltage does not get you higher rpm, even if you could build a pack above 680 VDC.


It is true that just adding more voltage does not change speed; in any AC motor, speed is determined by power supply frequency, given enough voltage to drive enough current to produce enough torque to keep the motor in synch (in the case of synchronous motors) or at an appropriate level of slip (in the case of induction motors).

But running faster certainly does require more voltage, as with any motor.



kennybobby said:


> To get the torque and speed needed for EVs requires a different winding with a pole count and inductance suitable for the frequency range, and with a wire gage that can handle the current at a lower supply voltage typical of EVs, e.g. OEMs ~360-400VDC. Then you need a controller or motor inverter than can produce 3-phase currents at much higher than 60 Hz.


The inverter frequency is not a problem. Of course any AC EV needs a variable-frequency inverter, and there's nothing special about 60 Hz; for instance, 6000 rpm in a 4-pole motor needs 200 Hz... and that's only midway up the speed range for a typical production EV. Production EVs can have much higher pole counts (a Leaf motor is apparently 8-pole and a BorgWarner HVH 250-series is 10-pole), so they run higher inverter output frequencies.

Yes, windings must be appropriate for the current which will be required, but that is true of DC motors as well. This returns us to the question of whether aftermarket EV AC motors (such as the "AC-" product line of HPEVS) can be pushed harder than their ratings (driving them at higher current and higher frequency, both requiring higher voltage)... and if not, why not?


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## Frankenfiftyfour (Jul 22, 2019)

Im somewhat little informed on this but Im looking to find a taper lock bushing with the bolt on hub all in a set. Im in the USA so does anyone know companies that sell them as a set? I have an 1 1/8th shaft on my motor. Im just trying to leave the guess work out of it, if any of you know where to get?

Thanks


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## electro wrks (Mar 5, 2012)

You can use a weld-on hub, and weld on and machine a flange to fit your application: http://www.linngear.com/part-type/type-w/

Or you can machine a taper-lock chain sprocket. The chain sprocket can be a used, worn-out one because you'll most likely machine away the teeth: http://www.linngear.com/part-type/taper-lock/

Other suppliers are Dodge, Browning,and Martin.


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## MattsAwesomeStuff (Aug 10, 2017)

*Re: Industrial AC motor notes*

I missed this set of replies earlier, oops.



kennybobby said:


> Most industrial AC motors (3-phase, ~480vac, 50 or 60Hz) are wound with lots of turns of small gage wire in the necessary pole pattern to achieve the desired speed of operation e.g. 3600, 1800, 1200 for 2,4,6 pole motors.


Ahh. Gotcha. I was somewhat hijacking an earlier comment about industrial 3ph motors, so, that answers that question.

I wiggled in my own use case, which isn't a 3ph mains ACIM, but an ACIM (4 pole) from a forklift, designed for 48v. It's almost certainly going to have thicker wires than one designed to run off the grid. So, hopefully it's going to be suitably wound for EV repurposing.

I don't know that I've actually seen anyone with an EV build that uses an AC forklift motor yet, which is why I'm both hesitant (is there a reason this won't work and why everyone has chosen differently so far?) and curious.


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## kennybobby (Aug 10, 2012)

Depends whether it is made for 3-phase or single (split) phase power at 48vac, plus the power or torque rating. Also with 4 poles it runs at 1800 rpm with 60 Hz current, 3600 @ 120 Hz, etc., so how much gearing will be a factor also to determine if it is suitable for an EV on the highway.


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## remy_martian (Feb 4, 2019)

I don't see what wire size has to do with anything, or whether it's AC or DC for that matter. The motor could care less whether it's "industrial", in a forklift or EV -- it is spec'd as AC or DC, as maximum safe RPM, torque, HP, volts and amps. "Industrial" means nothing in the grand scheme of relevance here. Whether someone's used an AC motor is completely irrelevant and needs design worries revectored to the important stuff.

A fan on a shaft being a characteristic of "industrial" motors is also BS -- a machine tool has a TEFC motor and is VFD rated (harmonics tolerant windings). TEFC is totally enclosed fan cooled...there's a separate motor for a fan that cools the motor. If there wasn't you could never run a CNC milling machine all day at 50RPM while splashing it with chip-filled job coolant as 440V 3 phase is lurking nearby.

"Repurposing" to an EV is meaningless. YOU need to figure out what you want for the vehicle's top speed, the grade of road you want to be able to cruise at, passing reserve, and, if you like bald rear tires, do the math on the torque you need to get the acceleration you want or that will break the tires so you can get all the hot chicks who dig the smell of burnt rubber.

That specification exercise gets flipped on its head when you pick a motor out of a junkpile, salvage one, or happen to have inherited one from your Uncle Martin's estate. At that point you have a motor and a car. You need to either close your eyes and hope for the best, only worrying about HP and top speed, or you do the math, applying nameplate ratings to the car and seeing if it works. In most cases, you'd aim for a top speed for direct drive/gearbox decisions and your 0-60 is what it is. Unless you decide to have several ratios behind the motor, in which case you can eek out a bit more acceleration at lower vehicle speeds.

There's no free lunch in all this. If you don't want to spin the motor at 15 grand, but at 1800 using a direct drive and "industrial" motor, it's going to be a big, heavy, chunk of iron. And, no, a forklift designer doesn't intentionally make the motor heavy -- that's an extremely expensive way to make ballast. S/he's out to make torque in a tight space using a human-safe pack voltage.

There's no such thing as "repurposing" for an EV. It's *purposing* a nameplate rating into a car you already have in mind. If that doesn't work well enough, you play games with overvoltage (which DOES affect the top speed of an AC motor, by the way), spinning it beyond rated limits hoping the shrapnel stays in the engine compartment for the increase in HP, upping the current through the windings (which are correcty sized for the nameplate rating by the manufacturer, not "smaller" because it's "industrial), or using a gearbox.

You either spec the car's performance and find a motor that meets your requirements, or you have a motor and a car, and you get what you get with perhaps a bit of tweaking to squeeze out all you can to better the (usually) craptastic vehicle performance. But it likely won't be a whole lot better and in most cases you'll be building a golf cart that looks like a car because you found a 10HP 3phase 440 volt (which has "smaller" windings) motor on Craigslist.

Building EV's is expensive and is a tradeoff -- you'll either pay the price out of your wallet or in vehicle performance. Unless you are opportunistic and lucky and pick up the pieces you need over several years, after which you're miffed because you bought a brushed DC motor years ago and the world has gone high speed, high voltage, brushless, so you then wait around for one of those to come along (don't ask how this is not a hypothetical scenario).


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## Frankenfiftyfour (Jul 22, 2019)

Frankenfiftyfour said:


> Im somewhat little informed on this but Im looking to find a taper lock bushing with the bolt on hub all in a set. Im in the USA so does anyone know companies that sell them as a set? I have an 1 1/8th shaft on my motor. Im just trying to leave the guess work out of it, if any of you know where to get?
> 
> Thanks


Are their any EV companies that sell them, or other good resources to buy them as a unit? I seem to find one place that sells the insert and then another that has the flange to bolt to the other side of the drive line


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## electro wrks (Mar 5, 2012)

Frankenfiftyfour said:


> Are their any EV companies that sell them, or other good resources to buy them as a unit? I seem to find one place that sells the insert and then another that has the flange to bolt to the other side of the drive line


 The Taper-Lock bushings(I think that's what you are referring to as an "insert") come in industrial standard sizes with a range of bore diameters for each size. That way a sprocket or flange can fit a range of shaft diameters by changing out the Taper-Lock bushing for one that fits the shaft it's going on.
You seem to have trouble understanding the design concepts of setting up this kind of drive line power transmission system. I suspect in this case you would be wise to have a specialist design and maybe set-up the system. A shop that specializes in custom cars, or a shop that does or sells industrial PT systems does this kind of work on a regular basis. It might be time to bring in a Pro.


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