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Which is the upper limit of load angle for which synchronous motor can run without losing its synchronism?
0 degree
45 degree
90 degree
120 degree
90 degree
The upper limit of the load angle for which a synchronous motor can run without losing its synchronism is 90 degrees. Beyond this angle, the motor may lose synchronism and fall out of phase with the supply voltage.
The upper limit of the load angle for which a synchronous motor can run without losing its synchronism is 90 degrees. Beyond this angle, the motor may lose synchronism and fall out of phase with the supply voltage.
P=3тАЛ3VphтАЛIphтАЛcos(╧Х)тАЛ тАФ Power in a three-phase system
T=KтЛЕ╬жтЛЕIaтАЛsin(╬┤) тАФ Torque equation for synchronous machines
Synchronous motors operate by maintaining a constant speed in synchrony with the line frequency. The load angle is the phase difference between the rotor's magnetic field and the stator's magnetic field. When the load angle exceeds 90 degrees, the torque developed becomes negative, causing the motor to lose synchronism.
Synchronous motors maintain synchronism between rotor and stator fields.
The load angle represents the torque developed by the motor, which is critical for operation.
Can operate at a constant speed regardless of load changes.
High efficiency at rated load.
Requires initial starting mechanism to reach synchronous speed.
Potential to lose synchronism under high load or disturbance.
Used in large industrial drives and synchronous generators.
Applicable in power factor correction systems.
The standard operating load angle for synchronous motors is typically less than or equal to 90 degrees.
Option A (0 degrees) implies no load, while options B (45 degrees) and D (120 degrees) exceed the limit for stability.
C is correct тАФ The synchronous motor can only maintain synchronism up to a load angle of 90 degrees.
Remember that the load angle must be monitored in synchronous motors to prevent loss of synchronism, especially in varying load conditions.