What is the ratio of slip in induction motor?

What is the ratio of slip in induction motor?

It is common to express the slip as the ratio between the shaft rotation speed and the synchronous magnetic field speed. When the rotor is not turning the slip is 100 %….Number of poles, frequencies and synchronous induction motor speed.

No. of Magnetic Poles Frequency (Hz)
50 60
4 1500 1800
6 1000 1200
8 750 900

How do you find the stator current of an induction motor?

Therefore, the frequency of induced current or voltage in the stator winding is f = Ns P/120—the supply frequency. When the rotor is stationary, s = 1. Under these conditions, the per phase rotor e.m.f. E2 has a frequency equal to that of supply frequency f.

How do you calculate the stator impedance of an induction motor?

Calculation of Power of Equivalent Circuit

  1. Find Zf and Zb.
  2. Find stator current which is given by Stator voltage/Total circuit impedance.
  3. Then find the input power which is given by.
  4. Power Developed (Pg) is the difference between forward field power and backward power.
  5. The rotor copper loss is given by- slip × Pg.

What is the formula for rotor turns per phase?

8. What is the formula for rotor turns per phase? Explanation: Firstly, the winding factor for stator is obtained along with the winding factor for stator. Next the ratio of the rotor voltage per phase to the stator voltage per phase.

What is slip formula?

If the revolving magnetic flux’s synchronous speed & the speed of rotor are Ns & Nr in the motor, then the speed among them can be equivalent to (Ns – Nr). So, slip can be determined as. S = (Ns – Nr) / Ns.

What is slip in 3 phase induction motor?

Slip in Induction Motor is the relative speed between the rotating magnetic flux and rotor expressed in terms of per unit synchronous speed. When a three phase power supply is connected to the three phase stator winding of induction motor, a rotating magnetic field is produced in the air gap.

How do you find the stator current?

The stator current is calculated by dividing the phase voltage by the equivalent complex impedance of the entire circuit shown. The speed of the stator magnetic field in radians per second is 4xPixf/poles. The speed of the rotor (mechanical speed) is the speed of the stator magnetic field minus the slip.

How do you find the frequency of an induction motor?

To calculate RPM for an AC induction motor, you multiply the frequency in Hertz (Hz) by 60 — for the number of seconds in a minute — by two for the negative and positive pulses in a cycle. You then divide by the number of poles the motor has: (Hz x 60 x 2) / number of poles = no-load RPM.

What is the range of clearance that can be left between rotor bars and the core?

The range is usually chosen between 0.15-0.4 mm.

How do you calculate rotor resistance of an induction motor?

Under normal working condition r2/s≫ r1, x1 and therefore the equation becomes, This equation shows that for a constant torque, the slip is directly proportional to the rotor resistance. If the resistance in the rotor circuit is increased, the slip is increased and the speed of the rotor is decreased.

How do you calculate unit slip?

What is Slip in an Induction Motor?

  1. Definition: In Induction Motor, a slip is a speed among the rotary magnetic flux as well as rotor expressed in terms of for every unit synchronous speed. It can be measured in dimensionless & the value of this motor cannot be zero.
  2. S = (Ns – Nr) / Ns.
  3. Slip = (Ns-Nr/Ns)*100.

What is the slip frequency?

Slip frequency can be measured by determining the phase angle traversed in a defined period. For example, with a slip setting of 2 seconds (0.055 Hz) and slip frequency of 0.04 Hz, an angle of approx 29° (elec) is traversed before synchronising is permitted, as shown in Fig 12.15.