# Lynch Motor - Upgrade



## eRev (Jan 10, 2009)

Wouldn't be asking if it didn't represent an appreciation for the brain-trust on this list...

Has anyone seen a Kevlar reinforced armature up-close and can describe the technique employed by Agni or third party approaches to reinforcement for rpm enhancement? 

Was thinking of Kevlar string (.0625) wetted w/ a suitably high-temp epoxy and tensioned around the armature periphery - I have a spare motor to experiment w/ but haven't opened it up yet - just trying to get a semblence of what to do to safe-keep my nuts: 

http://machdiamond.smugmug.com/Motorcycles/eRevMW-K75-Conversion/i-MPH2S6j/0/X2/IMG3320-X2.jpg

She runs spirited and effortlessly in 4th gear (meaning the thermals are excellent) the 1st stage belt system is easily capable of spinning faster - the limitation is the Altrax @ 90V. Or can it be pushed to 96V? (96V = 25% speed improvement which equals 70mph which is marginally capable for highway squirts and that's why I'm asking. Thanks!


----------



## Yabert (Feb 7, 2010)

eRev said:


> the limitation is the Altrax @ 90V. Or can it be pushed to 96V?


You can't. The Alltrax will probably shut down at more than 90v. 
You will need a new controller or change your gears/belt ratio.

Just to know, what is the motor RPM at your current max speed?


----------



## eRev (Jan 10, 2009)

Yabert said:


> You can't. The Alltrax will probably shut down at more than 90v.
> You will need a new controller or change your gears/belt ratio.
> 
> Just to know, what is the motor RPM at your current max speed?


3500 RPM give or take for 56.5mph.

After further thought - me thinks the reinforcement is required to keep the armature circuit clips from flying off when the thermals are high - if the assumption is that the clips are silver soldered and the additional load applied is modest then reinforcement is probably not necessary because the motor should self cool better with higher RPMs.

My shoe-string budget doesn't allow change-out of gearing or belt ratio and besides the pack draw is currently at 8C for max acceleration, so don't want to mess with taxing the pack further.

I can bump the pack voltage to 88V and live with that for a while I guess. The other curiosity is can the Altrax operate at a lower logic voltage (enable input) relative to a higher motor voltage? In other words - if the pack standing voltage is say 96V, but due to IR loss voltage droop when running the controller sees 90V or less (regulate the logic voltage to something less than 96V to mitigate shut-down) - I wonder if this may work?


----------



## Yabert (Feb 7, 2010)

That can't work!

The controller will don't pass any current when the voltage is over 90v, so the battery voltage will not drop bellow 90v.

I has this problem with my motorcycle. The resting voltage after a fresh charge (3.65v) was 88-89v (26s droping at 3.4v each) and sometime my 72v Logisystems don't start (90v max). I generally wait a bit and the voltage was droping at around 86-87v and at this voltage, the controller worked.



> I can bump the pack voltage to 88V


How many cells in parallel? 24s, 26s?

The charging voltage isn't generally the problem (3.6v). The problem can be the resting voltage after a min or two (around 3.35v, 3.4v).




> My shoe-string budget


In this case, it's a really nice conversion for tight budget!


----------



## eRev (Jan 10, 2009)

Yabert said:


> That can't work!
> 
> The controller will don't pass any current when the voltage is over 90v, so the battery voltage will not drop bellow 90v.
> 
> ...


 
Yabert - I understand what you're saying and it makes sense - thanks for the discussion. If I add (4) more cells then that puts me at 26S and given the typical 4hr+ rest time after charging I should be able to comply with the 90V limiit with such a simple modification.


----------

