Cursitor Doom wrote:

N_Cook wrote:

Pulley system increases torque at low speed of cutting Electronic
gubbins can only decrease torque at low speed

You would hardly notice any difference with a well-designed, modern
controller. I bought one for a 415V 3ph industrial lathe I bought, which
enables me to run it from 240V 1ph. The low speed torque is astounding -


** Torque from an electric motor depends mainly on current flow in the windings, so if a controller can supply the rated full load current at low rpms there is no loss of torque.

Controllers for induction motors ( aka Variable Frequency Drives) reduce the AC frequency and voltage fed to the motor to reduce rpms. Current flow is monitored so the windings do not overheat when the motor is heavily loaded or stalled.

But if increased torque is what is needed at low speeds, stick with the pulley system.


.... Phil