How to Choose the Right Motor with Brush for Your Application

The first step is to analyze what the motor is expected to do:

• What is the load it will drive? (weight, resistance)
• What speed (RPM) is required?
• Is continuous or intermittent operation expected?
• What operational environment will the motor be exposed to? (temperature, moisture, dust, chemicals)
• What size constraints exist in your design?

Brushed motors are ideal for applications requiring simple control, good torque at low speed, and where budget is limited. Typical uses include toys, tools, vacuum cleaners, and some industrial machines.

Voltage is a critical initial factor. Brushed motors commonly operate in ranges from 1.5V up to 48V DC. The power source (battery or power supply) will determine available voltage:

• Low voltage: for portable or battery-powered devices
• Higher voltages: (12V, 24V, or more) for rack-mounted or industrial setups

Selecting a motor voltage compatible with your power source ensures stable and efficient operation.

Speed (RPM) and torque (rotational force) demand are interrelated in motor selection:

• Torque: is needed to overcome load resistance. It varies with starting loads, acceleration, and operation.
• Speed: requirements depend on how fast the driven component must move.

Motor datasheets typically provide performance curves showing torque vs speed. Your required torque under load will guide you in selecting a motor that can handle peak and continuous torque without overheating or stalling.

General formula:

Power (kW) = (Torque (Nm) × Speed (RPM)) / 9550

The motor must fit within the mechanical space allotted. Larger motors generally provide more torque and power but may not be suitable if space is limited. Brushed motors come in various frame sizes; carefully measure or specify the maximum dimensions allowed.

Brushed motors use brushes that make physical contact to transfer current. This creates wear and sparking, which means:

• They may not be suitable for explosive or very dusty/fluid-heavy environments.
• Require periodic maintenance (brush replacement).
• Duty cycle matters — continuous operation motors require robust design and cooling, whereas intermittent cycles have less thermal stress.

If the environment is harsh, consider sealed or coated motors, or possibly brushless types if cost permits.

A gearbox can adjust speed and torque to better match application requirements. For low speed and high torque applications, a geared brushed motor may be best. For higher speed without gearbox, a direct drive may be preferable.

• Define voltage and power source
• Determine required speed and torque
• Check available physical space and select frame size
• Consider environmental exposure and duty cycle
• Decide if gearbox is necessary
• Review motor datasheets and curves to confirm performance
• Factor in maintenance and lifecycle costs
• Finalize motor winding types and customization options if needed

• Simple design and lower initial cost
• Good starting torque and low-speed control
• Easy to replace and repair
• Suitable for battery-operated and simple applications

• When high precision and low maintenance are required
• In environments prone to dust, chemicals, or explosives
• When high efficiency and longer motor life are critical

In such cases, brushless DC motors can often be a better investment.

This guide provides a structured approach to choose the appropriate brushed motor by evaluating your functional, electrical, mechanical, and environmental needs. Matching the motor correctly to your application reduces operational issues and improves system reliability and performance.