Wednesday, May 8, 2013

What's driving my EV

The Citroen DS Pallas ev will maintain the 5 speed gearbox. The original design was that it would be a direct drive motor to diff. The Citroen DS is a front-wheel-drive with inboard disk-brakes. If we were to go direct to diff, then we would need to replace the gearbox with a diff that has inboard disc brakes. The ideal diff would be one out of a Jaguar XJ. However, this would then require modifications to the half-shafts. 

I had a great evening last night with some EV mates and received a lot of valuable feedback.

So, being our first project, it has been decided that the least complicated method is to merely mate the motor to the gearbox. This would also give us a variety of ratios to choose from to get the best performance. The next question is, do we get rid of the clutch. Having talked to an EV owner, I am now tending to want to keep the clutch. Seeing the motor has almost no internal resistance and is as a result freewheeling from its own momentum during gearchange, one has to wait for it to slow-down to a certain speed before gear change can be effected. But the final decision has not been made yet and we shall investigate this further before we make the final decision.

The motor/controller combination already acquired for this conversion are and AC-31 "C" Face AC 3-phase induction motor and Curtis 1238-6501Controller. This is designed to be installed in a EV truck weighing over 2998lbs; the Citroen DS Pallas has a kerb weight of 2948lbs.  The motor is rated at up to 70hp up to 8000rpm and 130lbs torque. More torque at lower RPM's than its big brother, the AC-50. Motor size is about 9"x 13".  At only 85lbs, it is 50lbs lighter than the AC-50. Air cooled with internal fan and sensor for controller. The Curtis AC fully programmable Controller can be used with up to 105VDC putting out 550AMPS with regeneration.

Food for thought:
Current power plant

Engine capacity         2347 cc
Maximum torque 195 Nm (144 ft·lb) (19.9 kgm) at 2500 rpm

HPEVS AC31                 117 ft lb @ 0 - 1200 rpm @ 72v

Here's a link to somebody else that has converted the magnificent DS -

Let the fun begin!

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