Table of Contents
When would a synchronous motor be used?
In the fractional horsepower range, most synchronous motors are used where precise constant speed is required. These machines are commonly used in analog electric clocks, timers and other devices where correct time is required. In higher power industrial sizes, the synchronous motor provides two important functions.
What application would I use a synchronous motor and why?
Synchronous motors are normally used in applications in which a constant and precise speed is required. Typical applications of these low power motors are positioning machines. They are also used in robot actuators. Synchronous motors are also used in ball mills, watches, record players, and turntables.
Why synchronous motor operate at constant speed on every load?
If Damper winding is used to self start the motor, then after falling out of synchronism, the damper winding comes into action to achieve Magnetic Locking again. Hence the speed is always kept to synchronous speed.
Why synchronous motors run at a fixed speed?
Synchronous motors are constant speed motors. They run at the synchronous speed of the supply. They are generally used for constant speed operation under no load conditions such as to improve the power factor. Synchronous motors have fewer losses than induction motors at a given rating.
What is synchronous speed motor?
Synchronous speed is the speed of rotation of the magnetic field in a rotary machine. An induction motor always runs at a speed less than synchronous speed. If the motor is running at synchronous speed, then the torque generated by the motor equal to zero.
What factors determine the speed of a synchronous motor identify whether the speed is directly or inversely proportional to these factors?
The synchronous speed of an induction motor depends on the frequency of the power supply and on the number of poles for which the motor is wound. The higher the frequency, the faster a motor runs. The more poles the motor has, the slower it runs.
What is the difference between a synchronous and synchronous motor?
Synchronous motors are built with PM excitation, with nonexcited high magnetic saliency or with electromagnetically excited rotors (for large powers). Synchronous motors, as the name implies, rotate at a constant (synchronous) speed.
What are the advantages of synchronous motors above 1000 kW?
The last two factors are particularly important above 1000 kW. Synchronous motors are often used in large plants to drive the central air compressor. A large synchronous motor can be used to control the power factor of the whole plant, compensating the lagging power factor of a large number of medium and small induction motors.
Can a synchronous motor self start on AC power?
Synchronous motors are inherently not able to self-start on an AC power source with the utility frequency of 50 or 60 Hz. As stated in Chapter 1, this is because synchronous motors can develop a torque only when running at the synchronous speed.
What are the applications of synchronous motors in power plants?
Synchronous motors are often used in large plants to drive the central air compressor. A large synchronous motor can be used to control the power factor of the whole plant, compensating the lagging power factor of a large number of medium and small induction motors. View chapter Purchase book