What is the difference between a synchronous motor and a generator?

Answer 1

A DC generator is Direct Current most common in industrial environments.

Limited to DC equipment such as motors, cranes, certain types of lighting etc.

A AC generator is Alternating Current can be used in virtually every environment.

These are used for virtually everything from residential dwellings to large steel manufacturing facilities.

Answer 2

All mechanical generators of electricity look almost the same inside. The only difference is at the points where electricity leaves and returns to the generator.

Basic simplified explanation

A generator produces electricity in a form that looks like a linear sine wave: first it is positive and then negative.

To create AC electricity, the central shaft carrying windings - which is called the rotor - has slip rings connected to the ends of the winding. In a single-phase generator (more correctly called an "alternator") the outer slip ring is attached to one end of the rotor's winding and the inner slip ring is attached to the other end of the rotor's winding. (In a three-phase alternator there are three separate windings and three sets of slip rings. Each slip ring is connected to the ends of one pair of the windings in such a manner that no windings are shorted-out.) The slip rings are touched by fixed brushes to take off the AC current.

To generate DC electricity, the central shaft carries a part called a "commutator" which has many separate segments. Each segment in sequence around the commutator is connected to the opposite ends of the rotor's winding . As the rotor spins round, two fixed brushes diametrically opposite one another connect to those segments one by one. Thus, as the rotor spins, one brush always picks up the positive wire from the winding and the opposite brush picks up the negative wire from the winding. So, as the shaft rotates, the two brushes always remain positive or negative.

Answer 3

What we usually call an AC generator is really an alternator, and what we usually call a d.c. generator is really a dynamo.

In an alternator, the rotating part is the field coil, which is supplied with DC current to produce a rotating magnetic field. When the field rotates through the stator windings, it induces an AC voltage which becomes the output.

A DC generator, like the ones found on very old automobiles, is opposite - the field coils are fixed, and the output windings (armature) rotate. Although the voltage in the armature is technically AC, the output goes through a commutator - a pair of segmented brass or copper rings at the end of the armature. The commutator constantly switches the polarity of the output so that one terminal is always positive, effectively rectifying the output so that it is DC. A pair of carbon brushes that contact the spinning commutator are used to conduct the armature voltage to the load.

Answer 4

One generates power, the other uses it. Generators can operate as motors (called "motoring", which is usually a bad thing). Under special conditions a motor can operate as a generator as well.

Answer 5

armature used in synchronous gen is stationary but for dc its rotating