Single-phase motors induction

Single-Phase Sguirrel-cage Motors. Single-phase squirrel-cage induction motors are classified and defined as follows ... 

Single-Phase Synchronous Motors. Single-phase synchronous motors are constant-speed motors that operate in synchronism with line frequency. As with squirrel-cage induction motors, speed is determined by the number of pairs of poles and is always a ratio of the line frequency. 

In I 888 Nikola Tesla (1856-1943) at Columbus, Ohio, USA, invented the first induction motor which has become the basic prime mover to run the wheels of industry today. Below, for simplicity, we first discuss a polyphase and then a single-phase motor. 

Since the kW developed by a 3-0 winding is 50% more than by a 2-0 winding for the same value of stator current /, the economics of this principle is employed in an induction motor for general and industrial use. As standard practice, therefore, in a multi-phase system, only 3-0 induction motors are manufactured and employed, except for household appliances and applications, where mostly single-phase motors are ttsed. 

Rotating electrical machines, Starting performance of single-speed three-phase cage induction motors for voltages up to and including 660 V 8789/1996 BS EN 60034-12/1996 ... 

Single-phase Motors. Alternating-current single-phase motors are usually induction or series motors, although single-phase synchronous motors are available in the smaller ratings. 

Split-Phase Motor. A split-phase motor is a single-phase induction motor equipped with an auxiliary winding, displaced in magnetic position from, and connected in parallel with, the main winding. Note Unless otherwise specified, the auxiliary circuit is assumed to be opened when the motor has attained a predetermined speed. The term split-phase motor, used without qualification, described a motor to be used without impedance other than that offered by the motor windings themselves, other types being separately defined. 

Capacitor Motor. A capacitor motor is a single-phase induction motor with a main winding arranged for a direct connection to a source of power and an auxiliary winding connected in series with a capacitor. There are three types of capacitor motors, as follows ... 

Shaded-Pole Motor. A shaded-pole motor is a single-phase induction motor provided with an auxiliary short-circuited winding or windings displaced in magnetic position from the main winding. This makes the motor self-starting. 

Table 2-1 yields ballpark motor efficiencies. The table applies to three-phase induction motors only. For singlephase, multiply by about 0.8. Single-phase motors are not generally recommended above 10 HP. 

Motor M-hp, 110-volt, single-phase, 60-cycle, a-c, squirrel-cage, induction, 1,200 rpm... 

Alternating current for induction motors and furnaces (three phase and single phase) and... 

A cage rotor is used on single-phase a.c. motors, the turning force being produced in the way described previously for three-phase induction motors and shown in Fig. 2.49. Because both windings carry currents which are out of phase with each other, the motor is known as a split-phase motor. The phase... 

Figure 10.70 shows a single-phase CSI using thyristors. A three-phase version of this type of inverter is widely used in induction motor drives. 

Ordinary two-wire ac is called "single phase" electricity. Induction motors without commutators would have to be started mechanically (for example, by hand), if no special motor design were used with that kind of electric power source. Therefore some clever tricks are built into most motors to aid in starting. 

Like single-phase induction motors, synchronous motors cannot start themselves. They employ self-starting circuits. 

Electrical energy is furnished to the plant at 5000 volts, 50 cycles, three phase. Two 1300-kva. transformers step the voltage down to 115 volts. The 50-cycle power is converted to 500 cycles by alternators with a capacity of 36 kw. A single motor drives two alternators, and a self-induction coil is used to regulate the power factor and ensure operational stability. The 500-cycle current is stepped up to 10,000 volts for the tubular ozonizers and 18,000 to 20,000 volts for the plate type. 

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