EMCO F1P Step motor specs

After my last post I have learned alot about step motors. I have also manged to figure out the specs of the step motors found in the EMCO F1P, and as always the quality of this machine turns out to be stellar.

My sources are:

Article on oriental motor. Explains the inner workings of stepper motors beautifully.

Article on stepper motors courtesy Douglas Jones of the University of Iowa.

The step motors in the EMCO F1P have 10 wires coming out of them. The wires are connected in consecutive pairs, one pair per two oppositely facing windings inside the motor (10 windings). The motor has almost no resistance when turning the shaft in un-powered state. The stator inside the motor has 50 teeth.

From this, I have gathered that this is a bi-polar, uni-filar, 5-phase motor design with 50 * 10 = 500 steps and 360 / 500 = 0.72° rotation per step.

This kind of motor is less common, and requires a more complex/expensive driving circuit. It offers higher precision, less vibration and noise and more torque at mid to high speeds than the more traditional 2-phase designs. Also there are more ways in which the driving circuit can drive it.

This has made me determined to keep the motors and find a new controller for them during my retrofit-project.


Anatomy of a step motor

I decided in the beginning of 2015 to stop spending time on my EMCO F1P CNC machines instead of the main goal of the proejct. Ironically that made me spend more time on the CNC,because I need to get them out of the way quickly.

Long story short, I want to convert one to use a new control board but without sacrificing the step motors. So I have now carefully removed one step motor (Z-axiz) and opened it up to see what's inside it.

Based on what I have gathered from searching around and posting a question on stack exchangel, this motor is most likely a bipolar motor with 10 windings.

Some pictures:

10 coils

Coil wiring

5 Screws

Removed connector housing.

10 wires + ground.

Motor removed from belt

Belt drive with tacho generator

Heat-sink with thermal paste.