comments:
Thanks for sharing that. Did some research. The cheaper construction of the motor itself is likely the cause for the 200 RPM minimum, as the sensor is not able to give a high-enough resolution positional reading to the controller. Changing the controller is unlikely to help. I have major concerns for you completely bypassing the V belt. The V belt on industrial sewing machines is an important piece of safety equipment, both for the operator and for the equipment. It acts as a mechanical fuse if you get a jam, as the motor can continue spinning while the handwheel is fully stopped. It also is a vibration absorber, as the torque needed throughout the cycle is not perfectly even throughout. You can always swap to a smaller pulley inexpensively, and there are also inexpensive speed reducers for industrial sewing machines if you can't get the ratio you want by changing just the pulley. https://www.amazon.com/40mm-65mm-Industrial-Machine-Accessories-Attachments/dp/B0D4VY1XZS https://www.allbrands.com/products/39722-techsew-sr-speed-reducer-slows-down-handwheel-rpm