Find out which of the two motors, Electrical Engineering

Find out which of the two motors:

Two three-phase induction motors while connected across a 400 V, 50 Hz supply are running at 1440 and 940 RPM respectively. Find out which of the two motors is running at higher slip.

Solution

We know that f = 50 Hz and we may determine the synchronous speed for

P = 2, N s  = (120 × 50 )/2 = 3000 RPM

P = 4, N  = (120 × 50 )/4 = 1500 RPM

P = 6,     N s   = (120 × 50 )/6 = 1000 RPM

An induction motor runs at a speed somewhat less than the synchronous speed. Numbers of poles of the motor running at 1440 rpm must be 4 and Ns = 1500 rpm.

% Slip of the motor (A),

SA   = ((Ns - Nr) /Ns) × 100 = (1500 - 1440/1500) × 1000 = 4%

Numbers of poles of the motor running at 940 rpm must be six and

Ns = 1000 rpm.

The slip of the motor (B),

s B   = (1000 - 940 )/1000= 6%

Therefore the slip of the motor running at 940 rpm is higher than the slip of the motor running at 1440 rpm.

Posted Date: 2/5/2013 3:20:21 AM | Location : United States







Related Discussions:- Find out which of the two motors, Assignment Help, Ask Question on Find out which of the two motors, Get Answer, Expert's Help, Find out which of the two motors Discussions

Write discussion on Find out which of the two motors
Your posts are moderated
Related Questions
Your assignment is to write a one page paper answering the question posed below. One page is the absolute limit. (You must attach a technical appendix showing computer output for

0PERATION OF POWER TRANSMISSION (SPEED GOVERNORS)

Design a Mealy system whose output is 1 iff there have been exactly two 1's followed by a 0 and then a 1. (a) Assume overlapping is allowed (b) Assume overlapping is not

Given that a BJT has β = 60, an operating point defined by I CQ = 2.5 mA, and an Early voltage V A = 50 V. Find the small-signal equivalent circuit parameters g m , r o , and rπ.

Q. Input offset voltage of operational amplifier? When both inputs are tied to ground, i.e., both differential-mode and common-mode inputs are zero, the output should be zero.

Q. Give the principle of biasing a FET amplifier. To correctly bias the FET, the gate needs to be negative with respect to the source. Bias is obtained in the following manner:

Q. Describe CCITT  hierarchical  structure  of  switching  and  routing  using  block schematic.  Ans: Hierarchical network are capable of handling heavy traffic where req

Explain Eddy currents. Eddy currents: Magnetic materials placed as in alternating magnetic fields have eddy currents also induced in them. It is because the material is subject

Q. Transistor terminals in BJT ? BJTS have three terminals namely base terminal, emitter terminal and collector terminal .The emitter layer is a source of charge carriers and i

Diagram and explanation of cro