You might be surprised how many places electric motors are hiding. They power many of the tools, machines, and gadgets we use everyday! From your fridge, to your air conditioner, to the windows on your car, electric motors are all around us.
But they’re also a key component in all kinds of industrial systems. Conveyor systems, fans, pumps, and CNC machinery all rely on electric motors.
Let’s take a look at electric motors and how they work, discuss some tips and tricks, and examine some premium options from ABB along the way.
What Are Electric Motors?
Electric motors convert electrical energy into mechanical energy using magnetic fields. The two main components are the stator and the armature (also called a rotor).
The power that is supplied to the motor runs through the stator, which contains coils that generate a magnetic field. The armature, in turn, also generates its own magnetic field. These magnetic fields interact with and “push against” each other to create rotational motion. That force is applied to the motor’s shaft, which causes it to rotate– which continues the transmission of power on to the next component.
Types of Electric Motors
There are two main types of electric motors– alternating current (AC), and direct current (DC). Alternating current reverses the current direction periodically, and direct current flows in one direction only. If you plug something into a wall outlet in your home, you’re using AC. If you are powering something off of a battery, you’re using DC.
NEMA is an important classification of electric motors that are designed according to exacting standards from the National Electrical Manufacturers Association that can apply to AC or DC motors. These standards include dimensions, power output, and performance characteristics.
Common categories include general purpose (GP), severe duty (SD), and explosion proof (XP), which all refer to how well the motor operates under certain conditions. Severe duty is designed for harsh environments, for example, and explosion proof is designed to contain sparks or other fire catalysts within the motor casing itself.
Another important term to know is inverter duty electric motors. Inverter duty motors are designed to handle the varying demands of a variable frequency drive (VFD). A standard motor, when connected to a VFD, may experience issues like overheating, insulation breakdown, or wear due to the rapid voltage changes produced by the drive.
AC (Alternating Current) Electric Motors
AC motors run off of alternating current that comes from the power grid. They’re typically used in applications where high power and efficiency are required, such as in industrial machinery, HVAC systems, and household appliances.
Induction motors, which are the most common type of AC electric motor, are known for their durability and ability to run at constant speed under varying loads.
ABB is a leading manufacturer of NEMA industrial electric motors, with a wide product range. For example, their Severe Duty line is stocked with powerhouse AC induction motors for the chemical processing, mining, foundries, pulp and paper mills, waste management facilities, and petroleum/chemical sectors. These durable and tough motors, featuring cast-iron housing, are built for long, trouble-free life in all kinds of hazardous environments.
The Severe Duty line also offers a diverse range of customizable features, such as a field-modifiable conduit box, NEMA efficiency options, and power ratings up to 800 horsepower. Featuring Class F insulation, Class B Rise at full load, a Division 2 rating, and IP55 protection, the SD100 (pictured above right) and SD200 (pictured at right) are reliable, hard-working options for your facility.
Depending on your environmental conditions, you may need an electric motor that has specialized safety features. That could range from high IP (ingress protection) ratings, insulation systems, vibration dampening features, corrosion-resistant coatings, and reinforced bearings.
Another common safety feature is explosion proof housing. This contains any internal sparks or explosions, preventing ignition of flammable gasses or dust in hazardous areas. An example of this is a grain terminal, where flammable dust is abundant. 
ABB’s XP100 (at right) utilizes a totally enclosed cast iron construction, making it an electric motor you can trust in extreme and dangerous conditions. These motors are Class I rated for gasses (groups C&D), and rated Class 2 for dust (groups F&G). They also have an IP65 ingress protection rating,
There are also synchronous AC electric motors. In these motors, the rotation of the shaft is synchronized with the frequency of the supply current. They are less common than induction motors, and are found in applications requiring AC power and precise speed control like clocks and timers.
DC (Direct Current) Electric Motors
DC motors are powered by direct current that comes from a battery or DC power supply. DC is more stable than AC by nature, so it is often preferred for electronic devices that are more sensitive to changes in current. The biggest distinction in DC motors is whether they are brushed or brushless.
Brushed
These are the simplest type of DC electric motors, where the electric current flows through brushes that contact a rotating commutator, creating a magnetic field that drives the motor. A commutator is a mechanical switch that periodically reverses the direction of current flow. Brushed motors offer greater control, but also require more maintenance due to brush wear.
If you’re looking for a brushed product that lasts, ABB’s Baldor-Reliance DC motors offer performance and reliability in tough applications. Their round frame DC motors utilize permanent magnet technology optimizing the commutator, brushes and inertia to assure the best performance possible. Additionally, their wound field motors are designed with high-performance molded commutators that provide superior commutation throughout the speed range to ensure trouble-free operation.
Brushless
In brushless electric motors, the brushes and commutator are replaced by electronic controllers that manage the current flow, eliminating the need for brushes. Brushless motors are more efficient, produce less noise, and have a longer lifespan when compared to brushed motors.
Learn more about DC motors from ABB’s DC product specialist below:
Electric Motor Tips & Tricks
When deciding what electric motor is best for you, consider your power requirements and your available voltage.
Always make sure your motor matches your required power output. Then, determine the type of voltage your facility uses. It’s easiest to work with the voltage that is already available, but converters like transformers or VFDs (variable frequency drives) are an option when necessary.
Next, determine the speed required, and your mounting and enclosure needs. Making the right decision upfront is important– it will save you time and money in the long run. Also, consider purchasing a premium efficiency motor, like ABB’s Super Premium (SP4), to lower your energy consumption.
Once you’ve invested in the right electric motor, you’ll need to maintain it to ensure it continues working for the long haul. Despite electric motors’ low-maintenance reputation, you’ll still want to ensure you do the following regularly to avoid electric motor failure:
- Take the time to visually inspect your motor and remove any debris or buildup. Monitor the operating temperature to catch signs of overheating, and check electrical connections.
- Run the motor and listen for any unusual noises, and look for vibrations. Keeping the motor correctly aligned and balanced is critical for long term performance.
- Keep an eye on your electric motor bearings, as they absorb the most wear and tear.
- Ensure lubrication levels are at appropriate levels, and visually inspect for leaks.
- Don’t forget to inspect the equipment that the motor is running– problems further down your line can affect the longevity of your electric motor.
Talk to Electric Motor Experts
IBT has been providing industrial motor solutions for over 75 years. Our product experts are ready to answer any questions you might have about your existing or future electric motor needs.
We can also help with facility maintenance schedules, troubleshooting, and online training! Contact us today.
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