[TCML] SRSG Rotor Mods difficulty
Phil Tuck (hvtesla)
phil at hvtesla.com
Sat Aug 8 12:47:50 MDT 2009
Having successfully machined a 1500rpm motor in the past, I now wish to do
a (UK 50Hz 240v) 3000rpm one for my SRSG.
Previously, with the 1500rpm and based on advice from this group, I measured
the rotor diameter and used one quarter of the measurement as the width of
the machined flat. Like this:
Yesterday I machined a 3000rpm bench grinder using the 0.25 formula and the
motor just hunted afterwards without reaching a constant speed. Increasing
the input to 270v did not help either. This motor was poor quality anyway so
has now been discarded for other uses.
I have since been advised however that the 3000rpm motors do not respond so
well to machining as the 1500rpm, and may need more material removed.
Unfortunately I am never able to correctly identify the 'dead' pole as
illustrated at http://evolve000.4hv.org/tesla/tc2srsg.html My motors always
seem to differ to this.
I have now acquired a second 3000rpm motor (bench grinder) which is my last
attempt for a while. This rotor is 2.128 inches diameter, the motor itself
being rated at 250Watts (1/5 HP maybe??)
These are the windings of my second motor that I wish to modify, in
So any thoughts, do I still go for the 0.25 * diameter, or more, or even
less? And have other people found the 3000rpm motors to be a bit trickier
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