[TCML] SRSG Rotor Mods difficulty

["Phil Tuck (hvtesla)" <phil@xxxxxxxxxxx>]

Hello.

 

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:
http://www.hvtesla.com/images/tesla%20coil%20modding_motor.jpg

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
close-up:

http://www.hvtesla.com/temp_images/DSCF0680.JPG

http://www.hvtesla.com/temp_images/DSCF0682.JPG

http://www.hvtesla.com/temp_images/DSCF0686.JPG

http://www.hvtesla.com/temp_images/DSCF0687.JPG

 

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

 

 

 

Phil

 

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