Why Slip ring Induction motor is preferred for High starting Torque application.
Which induction motor has the highest starting torque?
2. Capacitor-start motor: The capacitor-start motor develops a much higher starting torque, i.e. 3.0 to 4.5 times the full-load torque.To obtain a high starting torque, the value of the starting capacitor must be large, and the resistance of starting winding must be low.
Do induction motors have high starting torque?
Slip ring induction motor has high starting torque. Because slip ring is connected through the resistance. When the supply is on the resistance is increases the phase difference is decrease due to this starting torque is increases.
Which will give the highest starting torque?
For 1st question A) Repulsion motor has high starting torque.
Which AC motor have high starting torque?
A capacitor start motor is a split-phase induction motor with a starting capacitor inserted in series with the startup winding, creating an LC circuit which produces a greater phase shift (and so, a much greater starting torque) than both split-phase and shaded pole motors.
What is low starting torque?
The starting torque of the motor is given by, … At start, the rotor reactance is large because slip of the motor at start is equal to unity. The large rotor reactance at start makes the starting torque of the motor poor. The motor draws about 5 to 6 times current of its full load current and produce very less torque.
How is rated torque calculated?
- Torque (lb.in) = 63,025 x Power (HP) / Speed (RPM)
- Power (HP) = Torque (lb.in) x Speed (RPM) / 63,025.
- Torque (N.m) = 9.5488 x Power (kW) / Speed (RPM)
- Power (kW) = Torque (N.m) x Speed (RPM) / 9.5488.
Why starting current is high in motor?
Why High Starting Currents:
Resistance and leakage reactance circuit consist of resistance and leakage reactance of stator and rotor of induction motor connected in series. A load resistance (variable) is connected in series to the fixed rotor and stator impedance. During starting of the motor, slip will be one.
How do you increase starting torque?
There are three ways to improve the starting torque of induction Motor
- Internal Rotor Resistance. The across the line starting torque at low speed can be increased by increasing the rotor resistance. …
- External Rotor Resistance. …
- Variable Voltage/Frequency.
Which motor is more efficient Mcq?
Two pole motor has better efficiency. Two pole motor has better rpm and noise performance.
What is the single phase induction motor?
A single phase induction motor consists of a single phase winding on the stator and a cage winding on the rotor. When a 1 phase supply is connected to the stator winding, a pulsating magnetic field is produced. In the pulsating field, the rotor does not rotate due to inertia.
When a motor speed of 5000 rpm is required which motor will you select?
When a motor speed of 5000 rpm is required, which motor will you select ? (D) Universal motor.
Are AC motors reversible?
In order to reverse the direction of an AC motor, the magnetic fields must be altered to provoke movement in the opposite direction. Since each wire consists of a positive and negative current within the magnetic fields, the flip-flopping of main and starter wires causes the motor to run in reverse rotation.
Why does induction motor draw high starting torque?
As the speed of the rotor is zero at the start, the rotor conductor will cut the maximum flux and the maximum voltage will be induced in the rotor. As the motor starts accelerating the speed of the rotor will align in the direction of synchronous speed of the motor and the slip will get reduced.