Repulsion-start induction-engine start
Repulsion-asynchronous motor runs on one principle of operation and, when almost up to speed, is transformed into another type of work. Very high twisting forces are made when starting with the repulsion between the magnetic pole fittings and the same kind of pole in the adjacent field of the stator with winding. The repelling force controlled and changed so that the speed of rotation of the armature is rising fast, and if not stopped, will continue to grow beyond a practical working speed. This prevents the speed-operated mechanical switch that causes the frame to act as the rotor electrically same as rotor single-phase induction motors. That is why the engine is called repulsion induction motor.
Stator this motor is built very much like that in splitphase or capacitor-start motor, but only to run or field windings are mounted inside. The end of the bells keep fittings and shaft position and hold the shaft bearings.
Valves composed of many separate coils of wire connected to segments of the switch.
Set at the other end of the valve are Governor of weight, slide bars, which pass through the stator core. These rods push short-circuit rings, mounted on the shaft on the switch end of the valve. Brushes and brush mounted in the switch end of the bell, and in brush, interconnected with heavy wire, press against the segments on the opposite side of the switch (see Fig. 7-12).
When the engine is stopped, the action of the Governor of the weight keeps short-circuit rings from touching the switch. When the power is on, and the current flows through the field of the stator winding, a current is induced in the coil form. Two brushes are United together as an electromagnetic coil that produces the North and South pole in the valve, positioned so that the North pole in the armature is near the North pole in the field of the stator windings. Since the poles are trying to push, repulsion produced in this case can be met only by one way: anchor turns and moves the armature coils of the field windings.
Reinforcement you can get faster and faster, accelerating until it reaches, that is approximately 80 percent of running speed. At this rate, the Governor of the weight of the fly and allow thrust to move. These thrust, which are parallel to the valve shaft, conduct short-circuit rings from the switch. Now, when the Governor came up to full speed, the cylinders can move together electrically, in the same manner that the cast aluminum wheels not in a cage rotor induction motor. This means that the engine runs as an asynchronous motor.
Repulsion-type induction motor can start very heavy, hard-to-turn loads without drawing too much current. They are made from 1/2 " up to 20 HP Engines of this type is used for large applications, such as air compressors, refrigeration equipment and large rises, and is especially useful in places where low line voltage problem.
This type of engine is no longer used in the refrigeration industry. Some older operating units can be found with this type of engine is still used...