My latest EV project

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Joined: 31/12/2016
Location: Australia
Posts: 974
Posted: 03:19am 20 Sep 2021      

  Quote  The problem is back EMF which resists high revs. The way around it is higher voltage.

Hi Greg,
Nice work, been watching your previous build for some time.
I did see a documentary a few weeks back about electric cars, mostly interested in the drive-train they have mostly moved to high voltage  very high speed motors (small in size) and then gear it down a lot, seems to be working well, sort of reminds me of these cordless drills (angle grinders) that are geared down and provide a lot of torque.

Years ago messing around with old car generators using them to power model electric trains, the 12v volt generators used to run quite well on 24v, they would always rev to a certain speed and go no further, at the time this suited the purpose.
Later on as an experiment we lowered the field voltage using a resistance bank, the result was less power to start up, but the motor would rev out a LOT higher and was not held back anymore, next idea was to switch the resistance onto the fields after the initial speed was reached, this worked but found it too fast and unsafe for the train track.
Not sure if this helps or not, just an idea.
Your Aluminium work is looking good.