With electric motors speed refers to how quickly the output shaft turns (either on the motor or gearbox) and is typically measured in revolutions per minute (RPM).
The required speed depends on your application and faster isn’t always better. For instance, a precision robotics system may need high-speed accuracy, whilst a patient hoist might need slower, controlled motion.
The speed of an electric motor is influenced by several key electrical, mechanical, and control factors. The exact mix depends on the type of motor (AC induction, synchronous, DC, brushless DC, stepper, etc.) However, 2 standout influences are both voltage supply and the load on the motor. A higher voltage can increase speed, but if there is too much load or friction it can, as a consequence, slow it down.
Understanding the required operating speed for your specific application helps ensure you don’t over-specify or under-power your motor which will affect efficiency and component life span.
Power represents how much work a motor can do over time which is a combination of torque and speed. Power is normally measured in watts (W) or horsepower (HP).
As the motor power depends directly on both torque and speed increasing either will raise the overall power output.
However, higher power also means greater energy consumption, which may not be suitable for your particular application. Therefore, choosing the right motor size for your task is important for both performance and efficiency.
Voltage is the electrical potential supplied to the motor and determines how much current flows through the motor windings, which affects both speed and torque.
Different applications require different voltage ratings. For example smaller DC motors may run at 12V or 24V, whilst larger industrial AC motors may require 230V or 400V.
Using the correct voltage ensures optimal performance and longevity; too high a voltage can damage the motor, while too low may result in poor torque and stalling. Neither is ideal.
Bringing it All Together
As we can see torque, speed, power and voltage are all very closely intertwined and reliant on each other. In order to procure the most efficient electric motor or geared motor solution for your specific application it’s essential to choose the correct combination of these elements. Each application will have different requirements. For example, a solution driving a conveyor belt will have very different requirements to one powering a fan or medical device.
Speed and torque are generally classified as being High, Moderate or Low and it is important to be aware of the difference.
Low to High Torque
High Torque – These motors are normally accompanied with gearboxes to produce between 500-5,000+ Nm and are ideal for industrial machinery, and heavy lifting motors.
Moderate Torque – These are between 50-500 Nm and are used in winches, fans and elevators.
Low Torque – This runs between 0-50 Nm and is good for small appliances, fans, and drone motors.
Low to Moderate Speed
High Speed – This is a motor that runs between 5,000-2,000+ RPM and is used in high speed drills, electric fans and drone motors. Small brushless DC motors can reach more than 50,000 RPM which is considered extremely high speed.
Moderate Speed – These motors run between 1,000-5,000 RPM and are often found in pumps, fans, and washing machines.
Low Speed – These run at 0-1,000 RPM and are used in cranes, winches and heavy industrial machinery.
Understanding these features and how they relate to your application is key. Here are some example specifications of common applications.
Conveyor Systems – These require high torque, low to moderate speed and moderate power. Conveyors often carry heavy loads and consistent speed and torque is more important than RPM.
Fans and Blowers – As air movement requires rotational speed rather than strength, fans and blowers require low torque, high speed and low to moderate power.
Door and Gate Operators – These motors require the strength to lift or swing doors reliably, smoothly and quietly. Therefore they require moderate torque, low speed and low power.
Medical and Laboratory Equipment – Equipment such as centrifuges, pumps, and automated lab systems are dependent on consistent speed and smooth operation and therefore rely on low torque, high speed and precise control.
Robotics and Automation – Depending on the specific task robotics often require rapid changes in direction and torque, switching from fine positioning to gripping or lifting. Therefore their motors need variable torque, highly controlled speed and precise power.
Industrial Mixers and Agitators – Such equipment requires strong, steady rotation to move viscous materials and therefore require a high torque, low speed and high power motor.
Mobility Aids and Small Machinery – Wheelchairs, hoists, or compact industrial drives require a moderate torque which ensures reliable movement and load handling, as well as low speed and moderate power to ensure smooth and quiet operation.
Partnering with Parvalux
When working with Parvalux to ensure the best solution for your electric drive requirements we will start with identifying:
- Load – how much torque is required
- Speed – required RPM for your process
- Duty cycle – how long the machinery must run continuously
- Voltage and power supply – requirement for optimal operation