Re: what is the max bus voltage, 300V?

[Lee Hart <leeahart@earthlink.net>]

Victor Tikhonov wrote:
> ADC was never meant to serve in a vehicle.

That's true. EVers use them because that's all they can get (easily).

> (BTW can anyone tell me what exactly is "advanced" in ADC motor?)

Nothing but the name!

> 18 kW Siemens motor which will give you the same max power as 9" ADC
> is 108 lb, 7.5 x 7.5 inches square in crossection and less than 15
> inches long.

An AC motor will be a little smaller than an equivalent DC motor,
because it doesn't have the brushes and commutator. But the inverter is
a little bigger.

This Siemens motor also has no internal fan, and requires external
cooling, correct? This also reduces its size compared to the ADC motor
which has an internal cooling fan.
 
The ultimate power that either the AC or DC motor can deliver is limited
by the controller (and possibly the batteries). Drag racers are using DC
motors because they can get much larger controllers for them.

> Either will sustain 80 kW of power between 4000 and 10000 RPM (as long
> as you run cold water through). That means you run on first or second
> gear all the time and have giant torque at the wheels.

It would be interesting to compare the torque-speed characteristics of
these motors if you assume the same battery pack and controller current
rating for each.

> These motors meant to be in a vehicle from very beginning

That is a big advantage for long-term reliability, and as a way to cut
down on the amount of custom engineering required to get it in a
vehicle.

> Try it with 9" ADC. Mathematically you can get the same torque at the
> wheels (on higher gear) but practically you twist shafts and stress
> gear box and the clutch beyond reliable operation.

I don't understand. The racers do this, of course -- they are producing
far more power than the original ICE components were designed for. if
the AC drive was producing the same power, it would be breaking things,
too.

> In the beginning SepEx DC could be chosen as well as AC. Why
> then there are more AC OEM passenger cars while inverters still
> more expensive than controllers for SepEx?

I suspect that it's because series DC is cheaper and easier than sepex
DC. Even though sepex DC performs better, the plain old series DC was
good enough to satisfy all the vehicle applications.

Recently, as controllers are getting cheaper, we have seen sepex DC
replacing series DC. Many golf carts are now sepex DC, where they used
to be series DC. Likewise, PM DC has been getting used more and more.

> I don't believe AC is there because it's a fashion today.

"Fashionable" might not be the best choice of word. What I meant by a
fashionable design is that an engineer picks the same design that
everyone else is using BECAUSE they are using it.
--
Lee A. Hart                Ring the bells that still can ring
814 8th Ave. N.            Forget your perfect offering
Sartell, MN 56377 USA      There is a crack in everything
leeahart_at_earthlink.net  That's how the light gets in - Leonard Cohen