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Discussion Starter · #1 ·
Hi All-

I know that some EV conversions make use of high horsepower toothed, flat belt drives. For example I know of a few dual motor setups that use a belt drive to link the motors together. Also, some motorcycles use similar belt drives.

For anybody here who is using such a setup, what is it, where did you get it, and what do you think of it?

I'm sorting out my next build on paper and its looking like such a belt drive is likely to be the best approach for the drivetrain design I want.

Cheers
 

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I've not used belt drive yet, but I have looked into it for my conversion.

The design tools on the Gates website are very useful for working out what size and type of belt you'll need, especially the DesignFlex web tool.
http://www.gates.com/index.cfm?location_id=560

The strongest belt I've found is the Gates Carbon belt.
http://www.gates.com/brochure.cfm?brochure=7468&location_id=11347
These belts have a non-standard tooth profile so have to be used with Gates' own sprockets, which naturally aren't cheap.
 

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There are 3 basic factors in belt sizing.

Horsepower, belt feet per minute & torque. In our ampere hungry DC series type motors The locked rotor torque can be unreal in certain cars & street dragsters. Limiting maximum current is one way to safely reduce belt & pulley sizes. Wet fuel engines average 1 lb of torque for each horsepower. Roughly.
A stalled series type forklift motor on relays will dim the lights & start twisting mild steel shafts if the motor " maximum current code " states ..unlimited. It can easily pull 20/40/80 times what a normal motor of the same size would at 1 rpm.

DC & AC drive motors can be real belt eaters. You really need to call the belt company & get a VERY GOOD application engineer to size the parts for you. Or have unlimited confidence in the EV drive motor controller to control the beast.
 

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Discussion Starter · #6 · (Edited)
Thanks for all the replies.

I'm looking at using an AC55 motor and DMOC445 inverter which I got my hands on this last fall, so maximum torque at the motor shaft will be about 200 foot pounds (per the specs on the setup I have). I know that (within reason) I can control the tension load on the belt by using larger or smaller pulleys.

My overall plan is to convert a Scion xB (first gen). I want to yank the entire engine/transaxle and replace them with the rear differential unit from a AWD, independent suspension SUV (like a ford escape or a larger subaru). I'll mount the AC55 above it, facing foward and drive the differential unit via the belt. A 2:1 reduction on the belt and a 3.5:1 reduction (typical for modern cars) in the diff should yield an overall reduction of 7:1 which for a fairly light car and the fairly torquey AC55 should give a good combination of acceleration and top speed.

Brian
 

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I have seen some sand rail dune buggys that use belt drives.

I saw one that had a belt from a clutch on the crankshaft that ran straight to a pulley with cv axles sticking out of it. Similar to your proposed driveline but without a differential as both axles had to rotate the same speed.

Either way the dune buggy community might have something easily adaptable to your application.

Also some large belt driven superchargers can require hundreds of horsepower to turn and they spin high rpm. Could be an off the shelf source for belts and pulleys if they were up to the task. I have never priced custom belt drives so I dont know how they would compare.

Sounds like it would be a sweet build.
 

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Thanks for all the replies.

I'm looking at using an AC55 motor and DMOC445 inverter which I got my hands on this last fall, so maximum torque at the motor shaft will be about 200 foot pounds (per the specs on the setup I have). I know that (within reason) I can control the tension load on the belt by using larger or smaller pulleys.

My overall plan is to convert a Scion xB (first gen). I want to yank the entire engine/transaxle and replace them with the rear differential unit from a AWD, independent suspension SUV (like a ford escape or a larger subaru). I'll mount the AC55 above it, facing foward and drive the differential unit via the belt. A 2:1 reduction on the belt and a 3.5:1 reduction (typical for modern cars) in the diff should yield an overall reduction of 7:1 which for a fairly light car and the fairly torquey AC55 should give a good combination of acceleration and top speed.

Brian
Brian,

Here is a link to a you tube showing exactly what you want to build

http://www.youtube.com/watch?v=DoFzOdqyBew&feature=related
Since it was built by a university the build information and specifications might still be available.

Hope it helps,
Jim
 

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There are toothed belts, but also multiple v-belts as one unit.





Motion industries can set you up with "split taper-lock bushed pulleys". You can change gearing in a few minutes by putting a different diameter pulley on the same bush.





Here is the multiple "banded" v-belt setup on my hydraulic hybrid build:
 

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Usually if you change 1 pulley. You will need to change both for a noticeable gear ratio change.

If you think out the idler arm location. It may prolong changing both pulleys each time.
 

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I just found (5 mins ago) that picture off a site for a brazilian home built airplane club. Ive emailed them to get the supplier's name and contact info.


I was envisioning this can be made for many EVs and eliminate the transmission and just put this to the yoke on the rear end or worked for a front wheel drive.

as far as handling the torque shawn lawless had a belt system in his rail dragster that had 4 ge motors with 4 zilla 2K controllers. because he had the four motors try to all work together the belkt skipped when he mashed the accelerator, but then after that it caught the gear and the rail dragster took off.

this belt system is trusted in airplanes! Id imagine they would work in an EV.

the gears could be changed for any gear ratio.

I have a 3.4 rearend, put this 1.81 ratio in between the motor and rear end and I have a perfect 6.19 ratio and will be able to get to 80 mph and the motor will only be at 6000 rpm.
 

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the motor will be a kostov 10 inch or 9 inch. they are rated for 5500 rpm, as far as even getting up to 80 I doubt it.

cruising up to 70 top speed is fine for me.
 
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