DIY Electric Car Forums banner

1 - 20 of 26 Posts

·
Registered
Joined
·
9 Posts
Discussion Starter #1
I have a 98 Ranger 4x4. I am going to convert it to EV. I have some experience with electronics, and rebuilding motors and pumps for a tree nursury I worked for. I have contacted Wrightspeed, they aren't talking. I would like to replace the differentials with 40 pound motors like they talk about on their website. Anyone have a souce for those motors.
Thanks,
WW
 

·
Registered
Joined
·
1,317 Posts
I have a 98 Ranger 4x4. I am going to convert it to EV. I have some experience with electronics, and rebuilding motors and pumps for a tree nursury I worked for. I have contacted Wrightspeed, they aren't talking. I would like to replace the differentials with 40 pound motors like they talk about on their website. Anyone have a souce for those motors.
Thanks,
WW
I think Wrightspeed is going after OEM's I would be surprised if they replied at all, even to say they don't deal with individuals. I'd say for us DIYer's we're stuck with good old DC motors, or the very few some what low powered AC systems available. I don't think you could ever get your hands on the guts of a Tesla S or these wrightspeed motors.
 

·
Registered
Joined
·
325 Posts
You did send them the non-refundable $60k deposit before contacting them right?

I have a 98 Ranger 4x4. I am going to convert it to EV. I have some experience with electronics, and rebuilding motors and pumps for a tree nursury I worked for. I have contacted Wrightspeed, they aren't talking. I would like to replace the differentials with 40 pound motors like they talk about on their website. Anyone have a souce for those motors.
Thanks,
WW
 

·
Registered
Joined
·
1,562 Posts
i'd just yank the ICE, use whatever motor you'd like. Same for batteries and controllers.

hub motors and the like are generally pricier and way more involved for the first try.
 

·
Registered
Joined
·
9 Posts
Discussion Starter #5
I think Wrightspeed is going after OEM's I would be surprised if they replied at all, even to say they don't deal with individuals. I'd say for us DIYer's we're stuck with good old DC motors, or the very few some what low powered AC systems available. I don't think you could ever get your hands on the guts of a Tesla S or these wrightspeed motors.
What about 2 low powered motors inline in place of the differential, with a magnetic coupler between them. The coupler could be disengaged when cornering, and engaged to act like a positrack. Could have the same at the front axel to have 4x4. The trick would be to match the axel speeds. Is this possible? Don't have the $60K, so Wrightspeed with have to struggle along without me.
 

·
Registered
Joined
·
290 Posts
What about 2 low powered motors inline in place of the differential, with a magnetic coupler between them. The coupler could be disengaged when cornering, and engaged to act like a positrack. Could have the same at the front axel to have 4x4. The trick would be to match the axel speeds. Is this possible? Don't have the $60K, so Wrightspeed with have to struggle along without me.
Why bother with the coupler? With DC motors in series, they act as an open differential, and in parallel they act as a limited-slip differential. So two slim DC motors back-to-back where the diff. used to be, combined with series/parallel switching and the necessary gearing to get them down to driving speed (Perhaps a Planetary gearset on the end of each motor) would give a vehicle with good low-speed maneuverability, a tendancy to pull straight at high speed (good for stability), and the capability to manually override if you need LSD-type behaviour (Traction in wet/icy conditions).

With AC motors, you would effectively need two controllers, and then it would act as you program it to, either allowing a limited amount of slip, or letting the wheels spin freely as necessary.
 

·
Registered
Joined
·
9 Posts
Discussion Starter #7
Why bother with the coupler? With DC motors in series, they act as an open differential, and in parallel they act as a limited-slip differential. So two slim DC motors back-to-back where the diff. used to be, combined with series/parallel switching and the necessary gearing to get them down to driving speed (Perhaps a Planetary gearset on the end of each motor) would give a vehicle with good low-speed maneuverability, a tendancy to pull straight at high speed (good for stability), and the capability to manually override if you need LSD-type behaviour (Traction in wet/icy conditions).

With AC motors, you would effectively need two controllers, and then it would act as you program it to, either allowing a limited amount of slip, or letting the wheels spin freely as necessary.
Would there be enough distance between the front wheels? If I put one motor at the rear like Ford did with the Ranger EV, and had the two slim DC motors back-to-back at the front, could it work without a tranny? What about reverse?
 

·
Registered
Joined
·
290 Posts
Again, this is all DC.

With a DC motor, the greater the torque necessary, the higher the resistance to overcome. So if you have two motors in parallel, the "outside" motor will have a lower resistance, and thus will get more power and spin faster. With the motors in series, both motors will be limited by the resistance of the slowest (highest torque) motor. So in a parallel system, the motors will try to push you round the corner tighter, whereas in a series system, the motors will try to straighten you out. It doesn't matter how far apart the wheels are, this effect will happen all the time, but the wider the track, the more pronounced the effect will be, same as with a regular differential.
With reverse, there would be no difference whatsoever. The effect would still be there, but given the (lack of) speed you'll be travelling at (Provided you're not doing Gymkhana or some other kind of high-speed sport) the effect would be negligible.
 

·
Registered
Joined
·
2,222 Posts
With a series wound DC motor the greater the rpm the greater the back EMF. 2 motors, 1 driving each wheel, wired in series will act like a convention open differential. If one motor starts to spin the system amps will quickly drop so the other motor will make less torque too. With both motors in parallel if one motor starts to spin faster the other motor will keep pulling.
 

·
Registered
Joined
·
325 Posts
What about 2 low powered motors inline in place of the differential, with a magnetic coupler between them. The coupler could be disengaged when cornering, and engaged to act like a positrack. Could have the same at the front axel to have 4x4. The trick would be to match the axel speeds. Is this possible? Don't have the $60K, so Wrightspeed with have to struggle along without me.
You need the gearing in the differentials, if you remove them,
you must replace with something that can give you the approximately 4:1 torque increase. Why not use the differential, this is a truck, weight isn't the biggest issue. Did you see what I proposed for the Samuri? A single motor that drives both differentials. You don't need the AC motors unless you are doing research. Very simple, no need for two or four motors.

What I'd like to test out is my design that eliminates the diff and uses a motor and two torque converters that go to the wheels.
This has some interesting properties, and could be a good solution, just need someone to fund the prototype.
 

·
Registered
Joined
·
504 Posts
First off, I believe Wrightspeed uses AC induction motors. They're built to spec for Wrightspeed, meaning that they're the only people who get them. Or the controllers.

If you put the gear reduction in the middle and the motors above and either front or back of the axles, you can have all the space you need for suspension.
 

·
Registered
Joined
·
9 Posts
Discussion Starter #12
You need the gearing in the differentials, if you remove them,
you must replace with something that can give you the approximately 4:1 torque increase. Why not use the differential, this is a truck, weight isn't the biggest issue. Did you see what I proposed for the Samuri? A single motor that drives both differentials. You don't need the AC motors unless you are doing research. Very simple, no need for two or four motors.

What I'd like to test out is my design that eliminates the diff and uses a motor and two torque converters that go to the wheels.
This has some interesting properties, and could be a good solution, just need someone to fund the prototype.
I would like to keep the weight down so that it could still be used as a truck. What I have now is a single ICE that drives both differentials. I can cut down on weight by eliminating the differentials, but if I have to add weight to get the 4:1 ratio then whats the point? It appears that most DIY EV use a single, large, heavy motor, and keep the tranny, driveline and differential.
As to using 2 torgue converters, this is where I was thinking of using a magnetic coupler. Magnetic couplers are used instead of VFDs to control large pumps.
 

·
Registered
Joined
·
325 Posts
.. I can cut down on weight by eliminating the differentials, but if I have to add weight to get the 4:1 ratio then whats the point?
Right, so you see my point. In my design, the torque converters can multiply torque and differentiate the wheel speeds, and lockup with no losses, and run the motor at low speeds where its most efficient and use half-shafts so the weight is off the wheels (sprung weight),
and it allows you to keep the motor turning, to operate accessories, and eliminates the problem with startup torque of AC motors, and isolates the motor from direct mechanical linkage to the harsh road environment.

This is heresy for old-time EVers, torque converters are devil ICE devices. But then it may work very poorly, it is just my theory at present.
 

·
Registered
Joined
·
9 Posts
Discussion Starter #14
Right, so you see my point. In my design, the torque converters can multiply torque and differentiate the wheel speeds, and lockup with no losses, and run the motor at low speeds where its most efficient and use half-shafts so the weight is off the wheels (sprung weight),
and it allows you to keep the motor turning, to operate accessories, and eliminates the problem with startup torque of AC motors, and isolates the motor from direct mechanical linkage to the harsh road environment.

This is heresy for old-time EVers, torque converters are devil ICE devices. But then it may work very poorly, it is just my theory at present.
If I'm understanding what you are saying, i replace the front differential with a DC motor with a torque converter at each end.
Could this set-up run with a DC motor and a torque converter in place of the existing driveline at the rear end?
 

·
Registered
Joined
·
325 Posts
If I'm understanding what you are saying, i replace the front differential with a DC motor with a torque converter at each end.
yes, but my design is to use an AC motor because it doesn't need to stop spinning and suffer from lack of startup torque. DC motors don't have that problem.

Could this set-up run with a DC motor and a torque converter in place of the existing driveline at the rear end?
yes but then much of the torque is already done through the diff gears.
It would be a simpler setup than the dual design.
 

·
Registered
Joined
·
290 Posts
Right, so you see my point. In my design, the torque converters can multiply torque and differentiate the wheel speeds, and lockup with no losses, and run the motor at low speeds where its most efficient and use half-shafts so the weight is off the wheels (sprung weight),
and it allows you to keep the motor turning, to operate accessories, and eliminates the problem with startup torque of AC motors, and isolates the motor from direct mechanical linkage to the harsh road environment.

This is heresy for old-time EVers, torque converters are devil ICE devices. But then it may work very poorly, it is just my theory at present.
If you have a halfway decent controller, startup torque is not a problem for AC motors. However, torque converters will always sacrifice 10% of the power going into them (at minimum), and require extra fluid circulation systems, to give you the "advantage" of being able to move your wheels at a different speed to your motor. And if you want to remove that advantage, it requires extra complexity (a lockup mechanism) to do it.

Alternatively, you can leave your motor connected directly to the wheel, and just give it less power. Rather than sacrificing 10% of your power to allow you to do something you will only need 10% of the time, why not sacrifice nothing?

If having torque converters in place was better than using a differential, then high-performance ICE vehicles would already have their fancy electronic diffs replaced with a simple bevel gearbox and a pair of torque converters. That they haven't, shows just how poor the "advantage" is.

If you're using DC, it's as simple as connecting the motors in series or parallel (or both if you want an electronic 2-stage gearing system). If you're using AC, you'll need 2 controllers. But as you'll already have to have 2 controllers (or one complex controller with two outputs, which will amount to the same thing, unless you're intending to have a shaft between the motors and keeping them in lockstep all of the time), you have absolutely no issue there.

Oh, and for what you're suggesting (mixing motor types) you're going to have problems anyway, unless you can get your differing motor/controllers with exact acceleration curves. If they don't match, you may have a "squashing" or "stretching" effect on the vehicle as one motor (set) moves faster than the other.
 

·
Registered
Joined
·
9 Posts
Discussion Starter #18
yes, but my design is to use an AC motor because it doesn't need to stop spinning and suffer from lack of startup torque. DC motors don't have that problem.
AC motor with torque converter at each end and short drivelines to the front wheels. Could the converters be from small car due to only needing to power one wheel?


yes but then much of the torque is already done through the diff gears.
It would be a simpler setup than the dual design.
DC motor direct into differential at rear end. Will this work with AC motor at front end?
 

·
Registered
Joined
·
504 Posts
WaterWizard,

I still don't know if you're using the Wrightspeed example just because it's a high performance car or if you're specifically after AC induction motors.

The wrightspeed uses ACIM with a gear reduction to adjust the speed to the wheels. They do NOT have a clutch or torque converter or multiple gear ratios of any sort. They have continuous connection between the wheels and motor. If the wheels are spinning, the motor is spinning. They also do NOT have any problems smoking the tires if they want to, and the 3 second 0-60 time speaks to the torque issue fairly well I think.

A top speed of 110 mph or so (the redline of the motor) means that any reasonable commuter vehicle COULD spec a single speed no clutch system the same way and have satisfactory performance for most needs.

I'm not saying that a series wound DC motor won't get better torque at low speeds. I'm only saying that there is concrete proof in the Wrightspeed and the Tesla that says an ACIM can perform extremely well for a car much more aggressive than most of us drive.
 

·
Registered
Joined
·
325 Posts
yep, with over $100k, you can build an amazing car.

WaterWizard,

I still don't know if you're using the Wrightspeed example just because it's a high performance car or if you're specifically after AC induction motors.

The wrightspeed uses ACIM with a gear reduction to adjust the speed to the wheels. They do NOT have a clutch or torque converter or multiple gear ratios of any sort. They have continuous connection between the wheels and motor. If the wheels are spinning, the motor is spinning. They also do NOT have any problems smoking the tires if they want to, and the 3 second 0-60 time speaks to the torque issue fairly well I think.

A top speed of 110 mph or so (the redline of the motor) means that any reasonable commuter vehicle COULD spec a single speed no clutch system the same way and have satisfactory performance for most needs.

I'm not saying that a series wound DC motor won't get better torque at low speeds. I'm only saying that there is concrete proof in the Wrightspeed and the Tesla that says an ACIM can perform extremely well for a car much more aggressive than most of us drive.
 
1 - 20 of 26 Posts
Top