24. NEMA-rated general-purpose motors can operate on voltages 610% of their rated nameplate voltage. An unbalanced voltage situation is extremely damaging to a motor. Calculate the expected heat rise in a motor subjected to an unbalanced voltage situation where the voltages between phases AB = 465 volts, BC = 487 volts, and CA = 473 volts. Add these voltages: Total Find the average voltage: Total ÷ 3 = volts Full Subtract the average voltage from the voltage reading that results in the greatest difference: volts 100 ÷ Greatest voltage difference/Average voltage = %voltage unbalance Temperature rise in the winding with highest current = 2 × (percent voltage unbalance)? % temperature rise in the winding with highest current

24. NEMA-rated general-purpose motors can operate on voltages 610% of their rated nameplate voltage. An unbalanced voltage situation is extremely damaging to a motor. Calculate the expected heat rise in a motor subjected to an unbalanced voltage situation where the voltages between phases AB = 465 volts, BC = 487 volts, and CA = 473 volts. Add these voltages: Total Find the average voltage: Total ÷ 3 = volts Full Subtract the average voltage from the voltage reading that results in the greatest difference: volts 100 ÷ Greatest voltage difference/Average voltage = %voltage unbalance Temperature rise in the winding with highest current = 2 × (percent voltage unbalance)? % temperature rise in the winding with highest current

Introductory Circuit Analysis (13th Edition)

13th Edition

ISBN:9780133923605

Author:Robert L. Boylestad

Publisher:Robert L. Boylestad

Chapter1: Introduction

Section: Chapter Questions

Problem 1P: Visit your local library (at school or home) and describe the extent to which it provides literature...

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Concept explainers

Three Phase Induction Motor

The induction motor is an electric motor that runs on AC (alternating current) and it is of two type single phase motor that work on single-phase power supply and three-phase motor that work on three-phase power supply.

Question

24. NEMA-rated general-purpose motors can operate on voltages 610% of their rated nameplate voltage. An unbalanced voltage situation is extremely damaging to a
motor. Calculate the expected heat rise in a motor subjected to an unbalanced voltage situation where the voltages between phases AB = 465 volts, BC = 487 volts,
and CA = 473 volts.
Add these
voltages:
Total
Find the average voltage: Total ÷ 3 =
volts
Full Bool
Subtract the average voltage from the voltage reading that results in the greatest difference:
volts
100 ÷ Greatest voltage difference/Average voltage =
%voltage unbalance
Temperature rise in the winding with highest current = 2 x (percent voltage unbalance)2
% temperature rise in
the winding with highest current
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