Hand Wound Arms

[eap9]

Hello Monty.

Id like to know if there is a big advantage in performance between a hand wound arm and a machine wound arm?

Are hand wound arms allowed in Box 12 racing?


Thanks,

Enrico

[Monty @ B.O.W.]

Enrico,

According to USRA rules, Group 12 arms (as well as all sanctioned winds that are slower than 12's) MUST be machine wound. Some of the ProSlot, RJR, or Koford arms in the last 5 or 6 years look close to handwound, but thats due to improved wnding machines that can be programmed for specific patterns. RJR was first, and the others had little choice but to follow along.

Armatures in Group 27, as well as all Open class or Eurosport arms are handwound. The larger wire and fewer turns make this more practical, but also more necessary. A single winding out of place among 17 per pole will stand out, cause imbalance and variences in inductance, while a few wires out of line in 50 or so turns is more negligible.

The major reason is certainly economic: The winding machine, while not cheap, still costs less than the annual salary of a skilled technician, but can easily wind armatures much faster. A handwinder, on the other hand, can wind different armatures with no reprogramming. If Open class armatures were a higher volume item, you might see machines doing those as well.

[PDM1]

Good answer Monty. Also a 12 arm must have a tag attached to the windings identifing the arm as a 12. If you hand wound your own arm, you might forget forget 1 or 2 of those 50 turns.

Paul

[eap9]

Hello Monty.

Thank you for your reply. The only reason why I asked is because of our "outlaw anything goes" box 12 racing where the only rule is the motor should be a c-can with ceramic magnets.

I just wanted to explore the possibility of a small advantage should it be obvious that a hand wound grp 12 arm for C-cans although expensive would be much faster. I also got information that cobalt 12 arms are hand wound and I know that they are also tagged X-12 since I have one C12 motor.

Regards,

Enrico

[Slotracer152]

if there are no rules...get you one of those C-can open arms

that'll give an advantage...and maybe a hole in the side of the track