: Provides low-speed torque compensation. If your mini lathe stalls under light cutting pressure at low RPMs, adjusting this trimpot clockwise optimizes low-end current limits. Be careful: cranking it too far causes violent motor pulsing or overheating. Troubleshooting Common JYMC-220B-I Faults Spindle Will Not Spin (But Panel Power LED is Active)
Most variations of the 2021 schematic utilize standard op-amps like the LM358 or dedicated timer ICs to compare the user's potentiometer voltage against an internally generated ramp wave synced to the AC line frequency. jymc220bi schematic 2021
