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Car alternator as R/C engine dyno?

Just wondering whether there is any merit in the idea of using an old
car alternator as a dynamometer for petrol powered R/C car engines.
 
R

Rheilly Phoull

Jan 1, 1970
0
Just wondering whether there is any merit in the idea of using an old
car alternator as a dynamometer for petrol powered R/C car engines.

Sounds good ta me !!
 
M

Mike

Jan 1, 1970
0
Just wondering whether there is any merit in the idea of using an old
car alternator as a dynamometer for petrol powered R/C car engines.

You sure can, though you'd have to factor in the low efficiency of
the alternator, should be possible to calibrate it with a known
electric motor and power supply. If you were in Perth, I'd give you
a hand and use a HP6813A as power source ;)


--
Regards
Mike
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J

John_H

Jan 1, 1970
0
Just wondering whether there is any merit in the idea of using an old
car alternator as a dynamometer for petrol powered R/C car engines.

No reason why an alternator wouldn't work if the revs and power
outputs match... and provided you don't mind the error due to
efficiency losses.

Since the power involved presumably isn't very great it's probably
also relatively easy to cobble up a dinkum Prony Brake. Only needs a
flat pulley, a lever actuated brake band and a spring balance.
 
R

rob

Jan 1, 1970
0
Just wondering whether there is any merit in the idea of using an old
car alternator as a dynamometer for petrol powered R/C car engines.

Would a geared down auto cabin fan (permanent magnet) motor connected to a
variable DC load using a couple of '3055's or whatever be more useful
perhaps.

Depending on the gearing you use the alternator might have too much inertia.
 
D

Dac

Jan 1, 1970
0
Just wondering whether there is any merit in the idea of using an old
car alternator as a dynamometer for petrol powered R/C car engines.

I once read an article that said the plastic/metal construction of the R/C
cars is so efficient that you can just measure the cars acceleration and
wheel rotation with a P.E beam across spokes etc. and get extremely accurate
value anyway. Would be a lot of work trying to get rpm and power with an
alternator.
 
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