Electrical Engineering ⇒ Topic : Causes of Hunting
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Sachin
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HUNTING OF SYNCHRONOUS MOTORS When the mechanical load is constant, the rotor settles down to an absolutely constant speed with the torque angle fixed by the particular delivered horsepower. Should the load be changed, however, the rotor speed changes momentarily until the torque angle adjusts itself to the new horsepower, if the load increases, the rotor slips backwards to an increased torque angle, while a load reduction causes the rotor to advance to a smaller torque angle. But because of the moment of inertia of the rotating parts, the rotor overshoots the final position. slowing down or speeding up more than it should.In slowing down as a result of an increased load, for example, it passes the proper torque angle, giving up some of the kinetic energ-y; under this condition, the motor develops more torque than it requires and speeds up. Acceleration to locate the correct torque angle causes the rotor to move forward a little more than it should; this results in less than the required torque, so that the motor slows down again. It may be understood that this periodic speed change is only momentary while the rotor is attempting to settle down to a correct torque angle and that it goes on while the averge speed is constant. This rapid forward and backward motion of the rotor as it revolves at the average constant speed is called 'hunting' (i.e., the rotor may be said to 'hunting' for its correct position with respect to the absolutely constant speed of the revolving field. | |
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Sachin
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HUNTING OF SYNCHRONOUS MOTORS When the mechanical load is constant, the rotor settles down to an absolutely constant speed with the torque angle fixed by the particular delivered horsepower. Should the load be changed, however, the rotor speed changes momentarily until the torque angle adjusts itself to the new horsepower, if the load increases, the rotor slips backwards to an increased torque angle, while a load reduction causes the rotor to advance to a smaller torque angle. But because of the moment of inertia of the rotating parts, the rotor overshoots the final position. slowing down or speeding up more than it should.In slowing down as a result of an increased load, for example, it passes the proper torque angle, giving up some of the kinetic energ-y; under this condition, the motor develops more torque than it requires and speeds up. Acceleration to locate the correct torque angle causes the rotor to move forward a little more than it should; this results in less than the required torque, so that the motor slows down again. It may be understood that this periodic speed change is only momentary while the rotor is attempting to settle down to a correct torque angle and that it goes on while the averge speed is constant. This rapid forward and backward motion of the rotor as it revolves at the average constant speed is called 'hunting' (i.e., the rotor may be said to 'hunting' for its correct position with respect to the absolutely constant speed of the revolving field. | |
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Lalan
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Causes of Hunting
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