[brian_]

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.

 

[brian_]

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?

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.

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.

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

... 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.

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

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

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.

 

[brian_]

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.

 

[brian_]

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.

 

[brian_]

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.

 

[brian_]

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.

 

[brian_]

@- 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.

 

[brian_]

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.

 

[brian_]

Re: 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.
...
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.

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.

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?