# Motor-to-Flywheel adaptor advice



## Duncan (Dec 8, 2008)

Hi Mad

How does that connect to the motor?


----------



## Mad Professor (Dec 18, 2010)

Thanks for your reply.

Sorry I was in a rush to put up the post before I had to go out.

I have updated my 1st post with more details, and pictures.


----------



## Duncan (Dec 8, 2008)

Hi Mad

It is going to be difficult/impossible to use that motor with a flywheel

The problem is a flywheel MUST be run centrally - any offset leads to large forces making the offset worse
It is called "whirl" 

If you went clutch-less and just used a light adapter to the gearbox input shaft you should be OK


----------



## CrazyAl (May 9, 2011)

Duncan said:


> Hi Mad
> 
> It is going to be difficult/impossible to use that motor with a flywheel
> 
> ...


Couldn't one get the flywheel machined and balanced so it is run centrally?
Whilst on the topic of flywheels, perhaps one can take the ring gear off as it won't be needed??


----------



## rwaudio (May 22, 2008)

I would look at rebirth auto's adapter plates, they have incorporated the coupler using bearings so the flywheel is supported. I don't think you could put a flywheel on that kind of shaft and expect good results.
http://rebirthauto.com/product-category/drive-systems/motor-adapters/rebirth-auto-premium-motor-adapters/


----------



## Duncan (Dec 8, 2008)

CrazyAl said:


> Couldn't one get the flywheel machined and balanced so it is run centrally?
> Whilst on the topic of flywheels, perhaps one can take the ring gear off as it won't be needed??



Definitely lose the ring gear!

The problem with this type of motor/driveshaft is that the driveshaft/adapter is not held rigidly by the motor's bearings
It will have a small amount of slop
This will lead to whirl


----------



## Ampster (Oct 6, 2012)

Yes, either a rebirth adapter for a clutch or keep it simple and ditch the clutch.

I wish I had gone clutchless on my VW. If your situation is like mine you may find you never need a clutch. I find that 2nd gives me an overall 10:1 ratio which is ideal in my situation. It is easy enough to shift when the car is stopped. I did try 3rd gear a couple of times and it gave me a higher top end. But I never go on the freeway with this car so that was useless. The car acellerated fine in 3rd but my AC35 has so much torque, the clutch was slipping. (Even with a 2500# pressure plate)
BTW, what kind of vehicle will you be building?


----------



## Mad Professor (Dec 18, 2010)

Thanks for all your replies and advice. 

I am still very undecided if I should go for the stock clutch setup, or go clutch-less.

The last thing I want to do is have to pull it all out again, once the project is finished, as the car is and will be the daily runner.

You can find my EV project here: Peugeot 205 EV

Best Regards.


----------



## PowerSurge (Jan 24, 2013)

Personally, I think you are going to have some serious issues using that motor. Because it's got basically a reversed attachment style, the only thing that's going to stop rotational twist is going to be that keyway. And a keyway is not designed to handle that kind of twist load. 

If I were dead set on using that motor, I would have an adapter machined like the one you have above, and have it professionally welded to that shaft to make it one piece. I really think any attempt to use a bolt on adapter on that reversed crank end is going to end in not so happy results.


----------



## Mad Professor (Dec 18, 2010)

PowerSurge: Thanks for your concerns regarding the motor in question.

The motor was removed from a Towrite 200 Series Milk Float Style Van.

I am not looking to be going down the drag-strip or anything like that, when finished the car is and will be the daily runner, so school runs, shopping, etc, etc.


----------



## Old.DSMer (May 18, 2012)

I would agree with the previous whirl concerns. If you weld that adapter, you should have the rotor/adapter assembly re-balanced. And I would finish machine the face AFTER welding to ensure axial alignment and a perpendicular mounting face. And that will be expensive.

Also don't forget about the clutch thrust loads (not sure what bearings are in that Kostov motor of yours). From what I've seen, most of the deep groove ball bearings used in electric motors can handle fairly substantial thrust loads. But better to verify and check before installation.

Using a separate bearing on the coupler would take up the clutch loads and handle the alignment issues. You could have the couper machined separately, which will be more cost effective. But that will be a trade-off for the added complexity of the adapter plate.

Is it just the camera playing tricks, or does that keyway look extremely shallow? If you do not weld/machine that adapter, ensure you calculate the load capacity of the keyway or it may shear and create some problems.

I guess you could also weld an extension shaft onto the existing one and go with a more "common" setup. I have not seen any hollow-shaft motors used in a conversion. I'll be interested to see the direction you take!


----------



## TEV (Nov 25, 2011)

I strongly advice you to go clutchless, I did so and I have no regrets, you only have to wait 1 second more between gears so if you don't race you are ok.

Also a clutchless setup will save you time, money and problems


----------



## shortbus (Sep 27, 2011)

Old.DSMer said:


> <SNIP>
> 
> Also don't forget about the clutch thrust loads (not sure what bearings are in that Kostov motor of yours). From what I've seen, most of the deep groove ball bearings used in electric motors can handle fairly substantial thrust loads. But better to verify and check before installation.
> 
> < SNIP>


According to the experts on board, there are NO clutch thrust loads. See this thread; 
http://www.diyelectriccar.com/forums/showthread.php?t=87559


----------



## Duncan (Dec 8, 2008)

shortbus said:


> According to the experts on board, there are NO clutch thrust loads. See this thread;
> http://www.diyelectriccar.com/forums/showthread.php?t=87559


No
You have read it wrong
There is a thrust load when the clutch is disengaged (pedal is pressed)
This is not the full release load but a load reduced by the leverage inside the clutch

This leverage is not very great - about 2:1 so there is still a substantial thrust load

Saying that most motor bearings I have seen should be OK


----------



## Old.DSMer (May 18, 2012)

> According to the experts on board, there are NO clutch thrust loads...


Correct - when engaged.

I should have been more descriptive.

As Duncan said - it would be the clutch _"release"_ thrust loads (based on the fulcrum ratio). My apologies for the misleading comment.


----------



## shortbus (Sep 27, 2011)

That was my argument that no one was willing to accept. A 500 pound plate load with a 2:1 on the diaphragm fingers, is still 250 pounds of axial thrust on the shaft when disengaging the clutch.


----------



## Old.DSMer (May 18, 2012)

shortbus said:


> That was my argument that no one was willing to accept. A 500 pound plate load with a 2:1 on the diaphragm fingers, is still 250 pounds of axial thrust on the shaft when disengaging the clutch.


Really? The only way the release thrust load is NOT passed to the motor is with an ADDITIONAL bearing between them. A "standard" clutch setup has to pass some thrust load. Otherwise it would never release - it would just slide.

I have not measured the ratio in my clutch - but it looks like about 3:1. Its a 2500lb pressure plate. That would result in approximately 833lb to release.

Never-the-less, most "modern" EV motors will handle this without issue. The trick with older rebuilt motors (like Mad Professors) is when radial bearings are used instead of deep groove ball. Radial bearings won't support the thrust release loads.


----------

