A Quick and Easy Guide to Industrial Motor SelectionFollow article
Nobody needs to tell you how useful motors are in industrial settings. From power tools and blowers to conveyors, robotic arms and pallet manipulators, they are everywhere.
If you find you need to choose a motor, it’s sometimes difficult to know where to begin. Here’s a quick guide to help you better understand the variables that go into industrial motor selection.
General Motor Characteristics to Know
First, let’s look at some questions to ask about your application and needs, and then go into specific types of motors and how they fit into the equation.
Here are some things you’ll need to ask before finding the right motor:
- Do you require a single-speed motor? This type of engine runs at an approximate or fixed speed with a simple on/off control and doesn’t require acceleration or deceleration. Either DC or AC motors are suitable in fixed-speed applications.
- Do you require a variable-speed motor? If your application requires precise speed changes, a variable-speed AC or DC motor will work for you. Centrifugal-based pumps, conveyors and fans are possible applications.
Apart from speed, the variability or constancy of several other variables apply as well:
- Horsepower: Cranes, conveyor belts and some types of pumps are all examples of where variable-horsepower motors come into play.
- Torque: Machines tasked with spooling or winding materials may require motors with constant torque but variable horsepower.
- Position control: Precise position control is a necessity in linear actuators and any place where a machine must hold multiple positions in sequence extremely accurately. Steel and paper mills are some of the primary benefactors.
- Speed: Motors are usually most efficient when allowed to run at or near their top speeds. That's why it’s important to know what you’ll require and whether it needs to change.
- Current: Motors must deliver predictable torque for you to get your intended work done. A motor’s operating current expresses how much it must draw to achieve that torque.
- Voltage: Higher-voltage motors deliver higher torque. Naturally, they require an environment that can supply the voltage needed to function. Too much can result in a loss of power or the motor itself.
A Closer Look at Types of Industrial Motors
Let’s go into more detail about some of the major motor types and look at industrial applications and industry trends driving choices.
One of the first factors to understand is whether your application is best served by a brushed or brushless motor. Here’s a brief rundown:
Brushed motors are put to use in a variety of lower-budget industries and basic functions, including in cranes, paper-making machines and steel mills, among many others.
They’re simple in construction, and that makes then inexpensive. They’re also good for achieving high torque and solid control at a range of lower speeds.
The downside is that the brushes require regular maintenance. However, subtypes of brushed motors can serve specialized functions. Shunt-wound brushed engines are useful in conveyors and vacuum applications owing to their constant speeds. Permanent magnet motors are better in servo systems, robotics and low-torque applications.
These require less maintenance than brush motors and generate less noise. Compared with brushed DC motors, they’re also more efficient and sport a better power density. They’re typically found in positioning, actuation and servo operations.
Brushless motors are more efficient than brushed motors, even though they’re capable of operating at higher speeds. They usually log more hours of operation over their service lives, too.
Other Industrial Motor Types
Here are some of the other industrial motor classes and types that are worth understanding in better detail:
- Stepper or torque control motors: Some industrial applications require very high holding torque to provide stability in multistep operations. Stepper motors deliver in those cases, at the expense of drawing lots of current almost constantly.
- Vibration motors: Some applications require a specific type of engine to deliver haptic feedback to the user. This includes some toys and consumer electronics, as well as medical and emergency alert devices.
- AC motors: AC motors are popular because they are economical with their electricity consumption at startup and are fairly simple to build and rebuild. They’re generally durable and require less frequent maintenance intervals. AC motors are good for applications that need fixed speeds without gear changes.
- AC single-phase and three-phase motors: AC motors come in single- and three-phase varieties. Single-phase AC motors are less powerful, but therein lies their advantage. Three-phase engines allow the transmission of a greater amount of electrical power. That’s important for infrastructural and heavy equipment needs.
Other Information on Choosing Industrial Motors
If you’re confused about AC versus DC motors and how it applies to power, don’t be any longer. DC power is more consistent in voltage than AC power and DC motors are simultaneously more efficient than AC motors. In fact, some accounts say they’re up to 30% more efficient.
For general industry purposes, AC brushless motors are coming into wider favour because they don’t need as much maintenance as some of the other options. The relative complexity of DC motors compared to AC motors makes them burdensome to repair.
The differences between motors that use bushings and those that use bearings should weigh on your decision as well. Motors with bearings perform radial movements of loads better and outlast motors with bushings.
With this rundown of some of the basics of choosing industrial motors, you should be on firmer footing. There are lots of variables to weigh, but also many industrial applications to suit. There are several choices because of all the general and speciality applications that require power and locomotion.