They’re found in appliances and toys throughout your house: remote control cars, electric can openers, computers, washing machines, electric mowers, electric toothbrushes, and much more. In fact, the electric motor might just be one of the most useful electrical inventions since Benjamin Franklin discovered electricity!
Most electric motors have a four-pole permanent magnet motor with double insulation design that runs at 120 volts. They work by adding electricity at one end, which sends a jolt to rotate the metal axle at the other end to power whichever machine the motor lives in.
What else should you know about these incredibly useful and common motors? Here are four things to keep in mind about their design and functioning.
1. They Work Using Electromagnetism
Those attending electrician school will learn electrical motor theory. When power is added, what really happens is that current flows through the motor’s coil to generate a magnetic force. One side of this force will flow in the direction the magnetic field is heading in, while a force generated on the other side of the housing will begin flowing the other way. Rotation on the armature thus happens, as an up-and-down action is created.
Most small household appliances like blenders and coffee grinders are run by a universal electric motor. This motor uses an electromagnet to take its energy from the DC or AC power feed, as the motor can be either AC or DC-powered.
2. Dynamic Braking Is Used for Safety
Most electric motors handle safety with the addition of a dynamic braking feature, also known as rheostatic braking. Located inside the circuitry of the motor, handle switch, and wire harness, the dynamic brake is activated upon the handle switch’s release. After the handle switch moves into the off position, the motor is brought to a complete halt.
There are also two other types of electric braking commonly found in the DC motor. Plugging—also called reverse current braking—gives greater braking torque than dynamic braking, and is more commonly used in larger machines such as printing presses and elevators. Regenerative braking is used when there is heavy inertia on the load on the motor, as one would find with an electric train.
3. Improper Maintenance Is the Leading Cause of Malfunction
Many electric motors will last longer if given the right level of care. Electric mowers and HVAC units are good examples of things needing regular maintenance, due to their exposure to grass, dirt, dust, and other contaminating elements.
At least once a year, an electric motor that can be contaminated in this way should be inspected and have all of its parts cleaned. This helps to avoid incidences of overheating by removing anything that may be clogging the filter and air cooling system of the machine.
4. Specialized Electrician Training Is Helpful for Attending to Repairs
To diagnose a problem with an electric motor, a technician with electrician training should start by using a digital multimeter to assess the components. Once a problem has been identified, the motor must often be disassembled to proceed with repairs. From there, the parts can be assessed for damage, corrosion, rust, or other contaminants. Brushes will often need to be replaced, along with any damaged parts, but rust and corrosion can usually be cleaned off with a wire brush.
Electric motors are an essential part of modern life, used to power all kinds of machinery in and out of the household. Most of the designs on these kinds of motors are built to last, and will tend to have a good lifespan as long as they are well-maintained. When problems occur, people rely on the specialist knowledge that those trained on electric motor theory can provide.
Interested in learning more about electric motors by receiving professional training at an electrician college?
Contact North American Trade Schools today for more information on our Construction & Maintenance Electrician Pre-Apprenticeship diploma program!
