How many losses are present in induction motors?
Explanation: There are 5 losses present in the induction motor. They are i) Stator copper losses, ii) Rotor copper losses, iii) Stator iron losses, iv) Friction and winding losses, v) Additional losses.
What are the different types of losses in motor?
Various types of losses, including rotational losses, reduce motor efficiency.
- Mechanical losses. As their name suggests, mechanical losses are caused by movement of the motor. …
- Magnetic losses (aka core losses or iron losses) …
- Copper losses (aka electrical losses or winding losses) …
- Brush losses. …
- Stray load losses.
What are stator losses?
= Stator Resistance The stator losses are a function of the stator winding resistance and directly proportional to square of stator currents, thus stator losses are inversely proportional to square of efficiency and power factor.
What is no load test of induction motor?
The no-load test of an induction motor is similar to the open-circuit test of a transformer. The motor is not connected from its load, and the rated voltage at the rated frequency is applied to the stator to run the motor without a load. The 2-wattmeter method measures the input power of the system.
What is the efficiency of induction motor?
Efficiency of three-phase induction motors can vary from 85% to 96%. See the chart below for torque vs. slip. Induction motors of 50-100 HP for industrial applications vary in weight from 700 to almost 1,000 lbs.
What is synchronous speed?
: a definite speed for an alternating-current machine that is dependent on the frequency of the supply circuit because the rotating member passes one pair of poles for each alternation of the alternating current.
What is core loss?
: energy wasted by hysteresis and eddy currents in a magnetic core (as of an armature or transformer)
What is back EMF in motor?
The back emf is represented as a variable emf that opposes the one driving the motor. Back emf is zero when the motor is not turning, and it increases proportionally to the motor’s angular velocity. Back emf is the generator output of a motor, and so it is proportional to the motor’s angular velocity ω.
How are stator losses calculated?
DC can measure the stator resistance. The hysteresis and eddy current loss in the conductors increase the resistance, and the effective resistance is taken at 1.2 times the DC resistance. The rotor copper loss is calculated by subtracting the stator copper loss from the total measured loss or the rotor I2R loss.
Why is the efficiency of induction motor so poor at high slips?
When an induction motor is started, the slip value is equal to 1 since the rotor is not moving. Therefore, the induced magnetic field and current in the rotor can be very large. This in turn causes a high current to be drawn by the stator that can cause damage to the motor if not controlled.
What is eddy current loss?
Eddy current loss is conductive I2R loss produced by circulating currents induced in response to AC flux linkage, flowing against the internal resistance of the core.
What is load test of induction motor?
The load test on induction motor is performed to compute its complete performance i.e. torque, slip, efficiency, power factor etc.
What is no load test of 3 phase induction motor?
No Load Test is an indirect method used for determining the efficiency and also to determine the circuit parameters of the equivalent circuit of the three-phase induction motors. The open-circuit test is performed on the transformer. The no-load test is the same as the open-circuit test performed on the transformer.
What happens when induction motor is loaded?
If the load on the induction motor is increased the current will increase to deliver the demanded power. The slip of the motor will increase with an increase of loading on the motor, and the speed of the motor will decrease accordingly.