Industrial electric motors power many essential pieces of equipment. As such, they consume approximately half of all power used worldwide.

Motors are often mismatched or oversized for the load they serve, and it’s important to replace them with energy-efficient models when they fail. To maximize efficiency, you must understand how to estimate motor part-load using input power and amperage measurements.

Commutator

The commutator is an essential component of electric motors and electrical generators. It switches power to the rotor's windings, reversing the direction of current in each coil with every half-turn. This turns alternating voltage into pulsating direct current that powers the external load circuit.

Without a commutator, the magnetic fields of the rotor and stator would collide, stopping the machine from turning. The commutator solves this problem by splitting the rotor's current-carrying winding into two separate circuits connected to the brushes on opposite sides of the split. This prevents sparking at the commutator, which can damage brushes or cause so-called brush fire. It also allows the brushes to be removed and replaced as needed. It's important to note that this is a dangerous procedure, and special PPE should be worn.

Armature

The armature houses the current-carrying coils and the magnetic field that powers the industrial electric motors. It also has a core, commutator and shaft. The armature is constructed from former-wound coils that are insulated from each other. They may be lap wound or wave wound. They connect to a commutator through slots that are lined with insulating material, typically a thermoset plastic or sheet mica. Some armatures feature slots that are twisted to reduce cogging and ensure a level rotation from one pole to the next.

The commutator transforms the alternating current generated by the coils into direct current for the motor to use. It also cuts the magnetic flux produced by the coils. This prevents the resulting armature reaction and protects brushes from sparking. It is composed of copper segments insulated by mica.

Shaft

A mechanical shaft in the motor spins when power flows through it. The motor is energized by either DC current from batteries or AC current from the electric grid or generators.

The rotor's magnetic field creates force that turns the shaft. The commutator and brushes allow the magnetic current to pass through the rotor, flipping the direction of electron flow at just the right moment. This applies Fleming's left-hand rule, creating an upward force on the shaft to turn it. At Applied, we carry a wide selection of industrial electric motors to help you complete your specific tasks. You can search by horsepower, RPM/Speed, phase, frame, voltage, enclosure, mounting and more to find the model that suits your needs. Contact us for more information about these models or any of our other products and services.

Air Gap

The air gap is an important component in a motor. It prevents rotor rub and helps dissipate heat in the stator during operation. It also plays a critical role in determining the performance of the magnets within the rotor. If the air gap is too large, it can reduce the power factor. This is because the magnetizing current required to build up a magnetic field in the rotor increases as the air gap length decreases.