Published November 9, 2010. Updated June 19, 2021.
A coil winder is essential when it comes to making a beautiful coil on large forms.
It takes considerable less time to wind large coils and varnishing the coils while they are rotating gives a much better finish.
Control of speed and acceleration is key issues when building a coil winder.
The best choice is to get a Variable Frequency Drive meant for 3 phased asynchronous induction motors, especially if the motor have a gear.
With a VFD it is possible to control the speed with a potentiometer, control start and stop with a single push and hold button and control ramp up and down times.
Having both hands free to guide the wire onto the form is important
27th March 2010
With materials at hand the motor was secured to a horse with a custom drive wheel with a rubber band to get contact to the form. A gear is attached to the motor with the ratio of 1:14, this makes it possible to run the motor at higher speeds with the VFD. Running at speeds close to its native speed makes cooling more efficient as its self cooled from the rear fan.
The form is pressed against the roller wheels which keeps the form in place.
Controlling the winders motor is done with a Siemens Micromaster Vector 0.37kW VFD, a potentiometer is used to adjust the speed and a foot pedal is used for start / stop. The VFD is programmed with a slow start ramp to avoid breaking the copper wire.
The machine was built without buying any new materials and is quickly put aside as the rollers are hold to the horses with welding clamps.
Further improvements could be a turn counter and automatic wire guide, but with the relatively low number of large coils I make there is other fields I like to focus on.
A time lapse movie of me winding 0.25 mm wire on a 160 mm diameter form.