: 0–90V DC (for 110V units) or 0–180V DC (for 220V units). Current Rating : Typically 12A to 13.5A DC.
: Sets the lower threshold voltage. Adjusts the slow creep of the spindle when the external speed dial is set to zero.
Turn the main speed knob to zero. Adjust the MIN trimpot until the motor just begins to hum, then back it off slightly so the lathe is completely stationary at zero setting. jymc220bi schematic full
The board coordinates high-amperage alternating current conversion alongside sensitive low-voltage potentiometer signals to establish stepless variable speed parameters. : 115V AC ( ) at 50/60 Hz. Maximum Current Capacity : 12 Amps continuous load.
Power enters the board through the main AC terminals (typically labeled L and N). : 0–90V DC (for 110V units) or 0–180V
The board features small trim pots for fine-tuning performance:
The commonly utilized to regulate small-to-medium workshop machinery. This heavy-duty board is most frequently encountered as the foundational electronic speed controller in mini lathes, variable-speed drill presses, and compact milling machines. Understanding its technical schematic layout, trace connections, and component distribution is vital for machinists and engineers seeking to diagnose, repair, or bypass faults on their shop equipment. Adjusts the slow creep of the spindle when
: Connects to the main 230V AC line via your lathe's primary power switch. Non-polarized, but standard practice routes live to L1 and neutral to L2 .
The version exposes the FB pin, allowing you to set any voltage between 2 V and 30 V (subject to input headroom). The formula is the same as for any buck regulator with a voltage‑feedback network:
Amplifies the fragile low-voltage PWM signal from the controller IC so it can decisively drive the power components.
Dictates how fast the lathe/motor spins up to the requested speed or slows down, protecting the motor and gears from sudden shocks.