Electric buses
 

On Fri, 17 Jul 2015 11:37:43 +0100
Recliner wrote:
On Fri, 17 Jul 2015 10:22:02 +0000 (UTC), y wrote:

On Fri, 17 Jul 2015 08:40:18 +0000 (UTC)
Recliner wrote:
The motors drive a single ratio transmission with an integrated
differential. Each motor is rated at 145kW but, more importantly, together
they also deliver a whopping 590lb ft of torque from standstill. Although
the power from the motors is 48kW down on the equivalent power from the
V12, the torque peak is 59lb ft, or 11 percent, up.

I don't know why the articles bother quoting torque since the amount of
torque
that reaches the wheels - which is what matters - depends on the gearing
ratios
as well as the motor.

The gearbox needs fewer ratio because of the high starting torque.

True, but once off the line it all gets a bit complex.

Most EVs only have a one or two-speed gear box.

I think most manufacturers seem to be trying to get away with a single speed
which means a compromise between acceleration and top speed (since even an
electic motor doesn't have an infinite rpm limit). I suspect in the future 2
speeds will be the norm since most people won't be happy with a 90mph max speed
especially in germany.

--
Spud

Electric buses
 

On Fri, 17 Jul 2015 11:23:44 +0000 (UTC), y wrote:

On Fri, 17 Jul 2015 11:37:43 +0100
Recliner wrote:
On Fri, 17 Jul 2015 10:22:02 +0000 (UTC), y wrote:

On Fri, 17 Jul 2015 08:40:18 +0000 (UTC)
Recliner wrote:
The motors drive a single ratio transmission with an integrated
differential. Each motor is rated at 145kW but, more importantly, together
they also deliver a whopping 590lb ft of torque from standstill. Although
the power from the motors is 48kW down on the equivalent power from the
V12, the torque peak is 59lb ft, or 11 percent, up.

I don't know why the articles bother quoting torque since the amount of
torque
that reaches the wheels - which is what matters - depends on the gearing
ratios
as well as the motor.

The gearbox needs fewer ratio because of the high starting torque.

True, but once off the line it all gets a bit complex.

Most EVs only have a one or two-speed gear box.

I think most manufacturers seem to be trying to get away with a single speed
which means a compromise between acceleration and top speed (since even an
electic motor doesn't have an infinite rpm limit). I suspect in the future 2
speeds will be the norm since most people won't be happy with a 90mph max speed
especially in germany.

Yes, higher performance EVs need a two-speed gearbox; the same cars
would probably have an eight-speed gearbox if powered by a petrol
engine.

Electric buses
 

On Thursday, 16 July 2015 20:09:03 UTC+1, Paul Corfield wrote:
312 - terminates at Croydon garage. Converts to full all electric
operation later this year using Optare Metrocity EVs. Has 2 for a
trial operation atm.

And very nice they are too! I just hope that full electric operation doesn't
mean exactly that and the double deckers that are run in the peaks on
the 312 continue - the route might be short but is busy enough in the
peaks to really need double deckers. (Singles are generally fine the rest
of the day)