📋 Overview
This PWM DC Motor Speed Controller lets you smoothly regulate the speed of a DC motor (or other DC load) from a complete stop to full speed. It works by rapidly switching the power supply on and off at 15 kHz — a technique called Pulse Width Modulation (PWM). By adjusting the ratio of on-time to off-time (the "duty cycle"), you control how much average power reaches the motor, which in turn controls its speed.
The controller accepts a wide input voltage range of 6V to 90V DC and can deliver a continuous current of up to 15A (1000W maximum power). Speed is adjusted using the included panel-mount potentiometer, which provides a smooth 0%–100% duty cycle range. For automated or remote-control applications, you can replace the potentiometer with a 0–5V analog control signal.
A user-replaceable 15A board-mounted fuse protects both the motor and the controller from overcurrent and short-circuit conditions.
Note: This is a speed controller only — it does not reverse motor direction. For direction control, you would need an H-bridge circuit or a reversing switch in addition to this module.
⚠️ Important: This controller works with brushed DC motors only. It is not compatible with AC motors or brushless (BLDC) motors, which require a dedicated ESC (Electronic Speed Controller).
⭐ Key Features
- Wide Voltage Range: Operates from 6V to 90V DC input
- High Current Capacity: Supports up to 15A continuous output current (1000W max)
- Smooth Speed Control: 0%–100% continuously adjustable duty cycle — no dead zones or steps
- 15 kHz PWM Frequency: High switching frequency means quiet operation with no audible motor whine
- Dual Control Options: Use the included potentiometer for manual control, or a 0–5V analog signal for automated/remote control
- Built-In Fuse Protection: User-replaceable 15A board-mounted fuse protects against overcurrent and short circuits
- Low Standby Current: Only 5 mA (0.005A) when idle
- Compact Design: Small footprint with screw terminals for easy, solderless wiring
📊 Specifications
| Parameter | Value |
|---|---|
| Input Supply Voltage | 6V – 90V DC |
| Maximum Output Power | 1000W |
| Maximum Continuous Output Current | 15A |
| Overcurrent / Short Circuit Protection | 15A fuse (user-replaceable, board-mounted) |
| Standby Current | 0.005A (5 mA) |
| PWM Frequency | 15 kHz |
| Duty Cycle Range | 0% – 100%, continuously adjustable |
| Speed Control Method | Potentiometer (included) or 0–5V analog signal |
| Operating Temperature | -20°C to 40°C |
| Dimensions (L × W × H) | Approx. 64 × 59 × 27 mm (2.5 x 2.3 x 1.1 inches) L × W × H |
| Weight | 69g (2.5 ounces) Approximate |
🔌 Wiring & Connections
The controller has clearly labeled screw terminals on the board. No soldering is required — just strip your wires and tighten the terminal screws.
Terminal Layout
| Terminal | Label | Description |
|---|---|---|
| Power + | + | Connect to the positive (+) terminal of your DC power supply |
| Power – | – | Connect to the negative (–) terminal of your DC power supply |
| Motor + | + | Connect to the positive (+) terminal of your DC motor |
| Motor – | – | Connect to the negative (–) terminal of your DC motor |
Analog Control Pins (Optional)
If you want to use a 0–5V analog signal instead of the potentiometer, the board provides two pins:
| Pin | Label | Description |
|---|---|---|
| Signal | 0V ~ 5V | Connect your 0–5V control signal here (middle pin) |
| Ground | GND | Connect the ground of your control signal source here |
🚀 Getting Started
Basic Setup (Potentiometer Control)
- Turn the potentiometer fully counter-clockwise (minimum speed / 0% duty cycle) before connecting power.
- Connect your DC power supply (6V–90V) to the terminals marked Power. Match polarity: positive (+) to positive, negative (–) to negative.
- Connect your DC motor to the terminals marked Motor. Match polarity: positive (+) to positive, negative (–) to negative.
- Apply power to the supply.
- Slowly turn the potentiometer clockwise to increase motor speed. Turn counter-clockwise to decrease speed.
Tip: Always start with the potentiometer at minimum (fully counter-clockwise) before applying power. This prevents the motor from suddenly spinning at full speed when you turn on the supply, which could be a safety hazard with larger motors.
Analog Signal Control (0–5V)
For automated or remote speed control — for example, from a microcontroller, PLC, or external voltage source — you can replace the potentiometer with a 0–5V analog signal:
- Disconnect the potentiometer from the board by unplugging its wiring harness.
- Connect your 0–5V control signal to the middle pin labeled 0V ~ 5V.
- Connect the ground wire of your control signal source to the pin labeled GND.
- 0V = motor stopped (0% duty cycle), 5V = full speed (100% duty cycle). Voltages in between provide proportional speed control.
Note: When using analog control, make sure the ground (GND) of your control signal source is connected to the GND pin on the controller board. Without a common ground reference, the controller may not respond correctly to the control signal.
🔧 How It Works
PWM (Pulse Width Modulation) is a technique for controlling power delivery by rapidly switching the output on and off at a fixed frequency. Instead of reducing the voltage to slow a motor (which wastes energy as heat), PWM delivers full-voltage pulses and varies the width (duration) of each pulse.
- Duty Cycle is the percentage of each cycle that the output is "on." A 50% duty cycle means the output is on half the time and off half the time, delivering roughly half the average power to the motor.
- 0% duty cycle = output always off (motor stopped)
- 100% duty cycle = output always on (motor at full speed)
- 15 kHz switching frequency means the output switches on and off 15,000 times per second — far too fast for the motor to "feel" individual pulses. The motor responds to the average power, resulting in smooth, quiet speed control.
The potentiometer (or 0–5V analog signal) sets the duty cycle. The controller's internal circuitry converts this setting into the corresponding PWM signal that drives the power MOSFET, which switches the motor current on and off.
🎯 Typical Applications
- DC Motor Speed Control: Fans, pumps, conveyor belts, power tools, robotics
- LED Dimming: High-power LED strips or arrays (within voltage and current limits)
- Heater Control: Resistive heating elements (within power limits)
- Solenoid / Actuator Control: Proportional control of linear actuators
- Test Bench: Variable-speed motor testing and prototyping
- Automated Systems: CNC machines, 3D printers, or PLC-controlled equipment (using 0–5V analog input)
💡 Tips & Best Practices
- Wire Gauge: Use wire rated for at least 15A for the power and motor connections. For runs longer than a few feet, use heavier gauge wire to minimize voltage drop. 14 AWG is a good minimum; 12 AWG or 10 AWG is better for longer runs or higher currents.
- Fuse Replacement: The board-mounted 15A fuse is user-replaceable. If the fuse blows, investigate the cause (overload, short circuit, stalled motor) before replacing it. Always replace with a fuse of the same rating (15A).
- Heat Management: At high currents (near 15A), the MOSFET and board will generate heat. Ensure adequate airflow around the module. If operating continuously at high loads, consider adding a small fan or heatsink.
- Motor Stall Current: A stalled (locked rotor) DC motor can draw many times its normal running current. If your motor's stall current exceeds 15A, the fuse will blow to protect the controller. This is normal and by design.
- Flyback Protection: DC motors are inductive loads. This controller includes built-in flyback protection, but for very large motors or long cable runs, adding an external flyback diode across the motor terminals is good practice.
- Potentiometer Mounting: The included potentiometer has a panel-mount design with a threaded bushing. You can mount it in an enclosure panel for a clean, professional installation.
- Power Supply Sizing: Make sure your DC power supply can deliver enough current for your motor's requirements. The controller can pass up to 15A, but your supply must be able to provide it.
🛠️ Troubleshooting
| Symptom | Possible Cause | Solution |
|---|---|---|
| Motor doesn't spin | Fuse blown | Check and replace the 15A board-mounted fuse. Investigate the cause before replacing. |
| Motor doesn't spin | Potentiometer at minimum | Turn the potentiometer clockwise to increase the duty cycle. |
| Motor doesn't spin | Wiring polarity reversed | Check that power supply and motor polarity match the terminal labels. |
| Motor doesn't spin | Supply voltage too low | Ensure your power supply is providing at least 6V DC. |
| Motor doesn't spin | Motor is not a DC motor | Controller only works with DC motors. It does not work with AC or brushless motors. |
| Motor runs but speed doesn't change | Potentiometer disconnected or faulty | Check the potentiometer wiring harness connection to the board. |
| Motor runs at full speed only | Potentiometer wiring issue | Verify the potentiometer harness is fully seated on the board header. |
| Fuse keeps blowing | Motor stall current exceeds 15A | Use a motor with a lower stall current, or prevent mechanical stalling. |
| Fuse keeps blowing | Short circuit in wiring | Inspect all wiring for bare conductors touching each other or the chassis. |
| Controller is very hot | Operating near maximum current | Improve airflow around the module. Add a fan or heatsink if needed. |
| Analog control not responding | No common ground | Connect the GND of your control signal source to the GND pin on the controller. |
⚠️ Important Notes
- Maximum Voltage: Do not exceed 90V DC input. Exceeding this can damage the controller's MOSFET and other components.
- Maximum Current: Do not exceed 15A continuous load. The fuse will blow at 15A to protect the circuit, but sustained overcurrent before the fuse trips can cause heat damage.
- Brushed DC Motors Only: Not compatible with AC motors or brushless (BLDC) motors — brushless motors require a dedicated ESC
- No Reverse Polarity Protection: Connecting the power supply with reversed polarity can permanently damage the controller. Always double-check polarity before applying power.
- No Motor Direction Control: This module controls speed only, not direction. To reverse motor direction, you need an external H-bridge or DPDT reversing switch.
- Not Waterproof: The controller board is an open PCB with no conformal coating or enclosure. Protect it from moisture, dust, and conductive debris. Use an appropriate enclosure for permanent installations.
- Operating Temperature: Rated for -20°C to 40°C ambient. Performance may degrade or the module may be damaged outside this range.
- High Voltage Safety: At supply voltages above 50V DC, the system presents a serious shock hazard. Use appropriate safety precautions, insulated tools, and ensure all connections are secure and insulated. If you are not experienced with high-voltage DC systems, seek assistance from a qualified person.
🏪 Where to Buy the 15A 6V-90V PWM DC Motor Speed Controller
This motor controller is availabel from Envistia Mall:
Buy the 15A 6V-90V PWM DC Motor Speed Controller →
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📚 Additional Resources
- PWM Motor Control Tutorial: Pulse Width Modulation for Motor Control — Electronics Tutorials
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VIDEO: 6v-90v 15a pwm dc motor speed controller Review & Testing with Different MotorsMotor Speed Controller Explained — Technoreview85 on Youtube
This guide is provided by Envistia Mall for educational and technical reference purposes. The manufacturer and Envistia LLC (dba Envistia Mall) are not responsible for any damages or losses resulting from the use of this product. Always follow proper electrical safety practices when working with electronic components. Specifications are based on manufacturer data and are subject to change without notice.