# Which type of motor can be easily reversed by switching two of the line leads?

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## What type of motors operate on the principle of a rotating magnetic field?

An AC motor is an electric motor driven by an alternating current (AC). The AC motor commonly consists of two basic parts, an outside stator having coils supplied with alternating current to produce a rotating magnetic field, and an inside rotor attached to the output shaft producing a second rotating magnetic field.

## What is the name of the motor part that rotates during operation?

With this simple understanding, we can divide any motor into two physical parts; one part which rotates—called the rotor—and one part which doesn’t— called the stator. Figure 1 shows a simple diagram of an electrical machine showing the rotor and stator. DC motors use DC current and voltage to power the motor.

## What is the stationary magnet of a DC motor represented by?

The stator is the stationary outside part of a motor. The rotor is the inner part which rotates. In the motor animations, red represents a magnet or winding with a north polarization, while green represents a magnet or winding with a south polariztion. Opposite, red and green, polarities attract.

## How many motor designs does a NEMA designate?

NEMA has established four different designs – A, B, C and D for electrical induction motors. Different motors with the same nominal horsepower may have different start current, torque curves, speeds and other variables.

## What is meant by rotating magnetic field?

A rotating magnetic field is the resultant magnetic field produced by a system of coils symmetrically placed and supplied with polyphase currents. … Rotating magnetic fields are often utilized for electromechanical applications, such as induction motors, electric generators and induction regulators.

## Is my motor AC or DC?

Look for the stator core construction and rotor. If there is no commutator, then it is a AC motor. If there is a commutator and brushes, it may be either a DC motor or an AC commutator motor (Universal motor).

## What is C face motor?

A “C-Face” motor is a common American mechanical standard designed with a rugged flange on the face of the motor for mounting purposes. The weight of the. motor is supported by the flange, which is most commonly attached to a gearbox. The flange is strong enough to cantilever the motor.

## How many types of stators are there?

Stator of Three Phase Induction Motor

Stator frame. Stator core. Stator winding or field winding.

## What is the first thing you should do when troubleshooting a motor?

For the supply, test first with the motor disconnect open and locked out. Use your megohmmeter to test the insulation resistance to ground.

Final tests and procedures.

1. Listen for unusual noises.
2. Smell for smoke or hot insulation.
3. Feel the motor for excessive heat or vibration.
4. Look for possible obstructions.
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## Which are the main parts of DC motor?

DC motors include two key components: a stator and an armature. The stator is the stationary part of a motor, while the armature rotates. In a DC motor, the stator provides a rotating magnetic field that drives the armature to rotate.

## Which motor is used in traction system?

AC traction motors have replaced DC motors in many traction applications. The motors used are induction or asynchronous motors designed to have characteristics suitable for traction. The speed and torque of the motor are controlled by varying the frequency, voltage and current applied to the stator coils.

## What are the parts of a DC motor?

These components are: a stator, a rotor, a yoke, poles, armature windings, field windings, commutator, and brushes.

## Which NEMA design motor has about a 5% slip?

NEMA Three Phase Electric Motor Designs

Basic Characteristics Normal locked rotor torque High slip
Slip 5 – 8%
Areas of Application High peak loads with or without flywheels such as punch presses, shears, elevators, extractors, winches, hoists, oil-well pumping and wire-drawing motors
Efficiency Low

## What is NEMA standard for motors?

NEMA is the North American standard for electric motors. NEMA is the publisher of NEMA MG 1-2014, a book that defines the manufacturing standards for alternating-current (AC) and direct-current (DC) motors in North America. The IEC is the standard for electric motors for the rest of the world.

## Which one is the most efficient method of braking?

Regenerative braking

It is the most efficient method of braking. In regenerative braking, the motor, instead of being disconnected from the supply, remains connected to the supply and returns the braking energy to the supply line.

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