Hi everyone who participated in the stepper motor mod
Can i first say it was probably the most frustrating ,time consuming problem ive ever had!!!.
Im sure every one else felt the same who had a go!!!.(hi fugus and weel done....i really mean it,you never gave in)
I did however have some good results in the mods i carried out to this motor,
The turning resistance (iron losses, eddy currents,coil losses)have been reduced by half(actually measured properly )
There is vertually no trace of cogging,and only a very slight drop in performance,in relation to rpm.
I did have the problem shelved for some time as i got fed up with it!!!
The way i did it was to grind off 1mm thickness across the full width of of the iron rotor(very acurately using a specially made jig )and then bond and wrap very thin plastic covered gardening wire around the full length of the rotor/coil very tightly along its length.
In effect giving the rotor a permanent shell of plastic covered steel wire.
I did think of using mig welding wire initially but i decided to have insulated metal wire instead ,hoping to eliminate some eddy currents,if there were any!!!.
I suppose you could class it as a slotless motor,as all the slots are now covered permanently with bonded wire.
I did cover the whole mod in varnish to add more containment of the bonded wire.
Overall the air gap was restored to normal by using the wire.....vertually no trace of cogging....its easier to tun than the unmodified one.
Unlikely to come apart as the iron core and windings remain stationary in operation......its the magnets that do all the moving.
Thanks for reading and cheers.