Dynamo and starter cases

[RobThomas]

Anyone know if the heavy steel frames of the dynamo and starter necessary for good/safe operation? Seems a bit of overkill.

[philthehill]

Rob
The rolled steel cases of the starter and dynamo are there because when they were originally manufactured they were cheap to produce.
So manufactures I presume thought why change a proven item as there was no proven need to change the materials used especially against production cost..
Even early pre-engaged starters had rolled steel bodies not like the current batch of pre-engaged starters which all seem to have alloy bodies.
The racing fraternity used to drill the rolled steel bodies until there was not much body left.
Everything else if it could be lightened by drilling was attacked.
Phil

[RobThomas]

I found a metre of Ali tube in , I think, 5251 that is almost a perfect match. I was looking at means of getting 12 volts from an Austin Seven and stumbled into this question. Thanks for the info. Might be worth investigating further, then.
Second dumb question...if the rotational direction was revesed, would a dynamo still charge? A bit of a 'how long is a piece of string' question, I guess.
Cheers
Rob

[geoberni]

Second dumb question...if the rotational direction was revesed, would a dynamo still charge?

Blimey, that's asking me to go back to electrical theory I learnt 44 years ago and never used as it was so basic.
It'll still generate the voltage, but I can't remember if the polarity would be reversed. So not an insurmountable problem.

Why do you ask, as really early car dynamos were 3 brush, not 2 brush, so that would be a factor too.

[alanworland]

'Modern' starters are a lot smaller and lighter than older designs and probably generate a lot more umph.
I recently serviced my 20 year old Bosch starter motor, quite a compact unit, which was fine but I was amazed to find the reduction gearbox using nylon gears!

Alan