The springs in the clutch center, and the torque-limiting nature of
the clutch itself serve to limit peak torque in the transmission and
driveline. The transmission and the driveline components need the clutch
and its center springs to survive long-term.
It is not the torque _from_ the motor that is the source of the
torque peaks, it is bumps in the road, like rail road tracks, that
inject damaging torque spikes _into_ the driveline and transmission. No
clutch to slip a little bit, or clutch center springs to absorb these
spikes, and the transmission life becomes very very short.
Bill D.
On 1/29/2017 7:28 PM, Tom Keenan via EV wrote:
I also have an older DC powered conversion with a clutch. I've found that
shifting with the clutch is much faster and much more forgiving. I've driven
it 'clutchless' a couple of times as an exercise, but found it to be very slow
to shift with the foot off the clutch. Matching motor speed with selected gear
normally results in time wasted between gears waiting for the motor to wind
down - traffic behind becomes very intolerant if you miss the split second
between go and no-go.
Tougher on hills because the vehicle may slow down to almost nothing before the
motor winds down enough to shift clutchless. Then you are back to square one
(first gear again).
However, since AC motors have a much wider RPM operating range, frequent
shifting isn't really necessary as with most DC motor conversions.
One conversion I've seen with an AC motor was a clutchless Geo Metro
(Solectria). The AC motor twisted off the transmission input shaft in that
particular vehicle twice, requiring a transmission replacement both times.
Might be a poorly matched transmission design, or it might be that the clutch
provides a bit of overtorque protection.
Based on what I've seen and operated for the last few years, I'd recommend
retaining the clutch. If you have a clutch-type conversion of any type
available to test drive in your area, try to drive it both ways to see what
fits your driving style before you commit.
Tom Keenan
On Jan 29, 2017, at 4:59 PM, Jay Summet via EV <ev@lists.evdl.org> wrote:
I have an S-10 conversion with the clutch left out, and you certainly can shift
it without the clutch. But the shifts take several seconds as you wait for the
motor to sync up in speed, and the time I spend coasting, unless planned well
in advance to be going down a hill, etc, can cause cars to ride up on me.
If I were do another conversion, I would probably leave the clutch in, despite
the efficiency hit, just so that you can shift quickly. That way you could
start in 1st and shift to 2nd quickly, instead of using extra amps to start up
(slowly) in 2nd.
I have a DC motor, so I find myself shifting between 2nd and 3rd gear around 40
MPH. Perhaps with an AC motor that has a larger RPM range you could get 0-50
which would be fine for all city driving, or even 0-60 MPH in one gear and
shifting wouldn't be much of an issue.
Jay
On 01/29/2017 05:24 PM, Cruisin via EV wrote:
It doesn't surprise me of the lack of support from HPEVS. maybe their door is
locked
Regarding the AC-31 which I have a lot of experience with, the motor already
has a
front bearing. The information you received from the seller of the motor is
false. Do your
conversion but leave out the flywheel and clutch assembly. If you want to
shift, it can be done
without a clutch as long as you are not using regeneration, else you will
have to feather the
accelerator during the shift. NO CLUTCH NEEDED.
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