Calculate the induction motor efficiency, Mechanical Engineering

Question:

Characterisation tests have been performed on a four pole, 415 V (line to line), three phase, star connected, 50Hz induction motor, with the following results:

  • No-load test : 415Vl-l, 3.76A, 234.3 W/phase.

(obtained at synchronous speed with a drive motor supplying the rotational losses of the drive system)

  • Locked rotor test: 163.8 Vl-l, 30A, 603 W/phase.

a)  Draw the per phase approximate equivalent circuit model of the induction motor, with all elements "stator-referred". Identify the physical significance of each element in the model.

b)  Using the characterisation data, calculate the "stator-referred" induction motor parameters. Assume that the shunt elements are much larger than the series terms. Remember that the measured input voltages are "line-to-line", not phase voltages.

c)  A load test is performed on the induction motor, which is fed from a 415Vl-l 50Hz supply, and the rotor speed is measured to be 1410rpm. Calculate the output mechanical power and mechanical torque for this test if the rotational losses constitute 880W for this condition. [Hint : Assume that the stator and rotor winding resistances are split equally].

d)  Calculate the induction motor efficiency for the load test described in (c).

e)  It is required to run the induction motor at a no-load zero slip speed of 900 rpm. Neglecting rotational losses, what must the supply voltage and frequency be in order to achieve this speed?

Posted Date: 2/18/2013 2:43:17 AM | Location : United States






Your posts are moderated
Related Questions
The Radial Dimension Commands There are 2 main radial dimension commands, DIMDIAMETER & DIMRADIUS. Both commands result in  similar looking dimension so AutoCAD automatically i

T ype s of Loading: Mainly three types of load acts on any beam; 1. Concentrated load ( or point load) 2. Uniformly distributed load 3. Uniformly varying load

what is second law of thermodynamics

An inside cylinder locomotive has its cylinder centre lines 0.70m apart and has a stroke of 0.60m. Rotating mass per cylinder = 150kg Distance between wheel Centre lines = 1.


Q. Design Stairways - Ladders and Platforms? Stairways, rather than ladders, should be provided for main access to elevated structures. Ladders should be reserved for isolated

A radically inward flow turbine working under a head of 10 m and running at 250 rpm develops 185 KW at the turbine shaft. At inlet tip of the runner vane, the peripheral velocity o

Hill Roads: Alignment Selection and Geometric Design Standards Here, you have already learnt how an alignment of a hill road has to be selected. The selection of a g

Heat Treatment of Stainless Steels: Stainless steels, as other steels, react to heat treatments over broad range. They are subjected to one or more of the given heat treatmen

relation between fluid pressure and velocity