Harmar Platform Lift DC motor PWM Speed Controller Board

Setting the speed to your model's ideal specifications will require technical knowledge not provided with this board's instructions.

This potentiometer PCB regulates lift motor speed over 0–100 % via PWM control on Harmar & Summit VPL units.

Designed for DC lifts, this PWM‑based speed control board accepts 12 V or 24 V input (jumper selectable) and drives the motor up to 30 A with a constant 100 Hz switching frequency. Compatible with many Harmar/Summit wheelchair lift models as a replacement for legacy potentiometer board part 46103.

Product Description
This engineered PWM module features a potentiometer control to vary motor speed smoothly without sacrificing torque. Jumper-selectable for 12 V or 24 V operation, the board operates at a steady 100 Hz switching frequency for stable output. Ideal for platform lifts originally equipped with Harmar part #46103, this PCB facilitates clean replacement and retrofit installations. Its compact layout (approx. 100 × 40 mm) fits within standard enclosures; ventilation or a heat sink is advisable when operating at high current loads.

Specifications

• Power supply voltage: 12 VDC or 24 VDC (jumper selectable)
• Maximum motor current: 30 A DC
• PWM frequency: ~100 Hz
• Speed control range: 0 – 100 % output via potentiometer
• PCB dimensions: approx. 3.85″ × 1.59″ (100 × 40 mm)
• Potentiometer interface: standard knob pot)

The board offers a cost‑effective, rugged upgrade path for older and newer Harmar VPL installs requiring potentiometer-based speed control.

As with all lift parts, this speed control board should be installed only by qualified technicians following safe handling practices. Proper installation and adequate cooling are essential to ensure reliable performance in vertical platform lift systems.