ENG H192 Hands-on Lab
LAB 3: Product Analysis
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Fundamentals of Engineering – Honors – ENGR H192
Product Analysis
Objectives:
 Combine previous lab experiences to better understand the
workings of a completed product.
 Develop an appreciation for horsepower and wattage
considerations in product design.
 Expand the library of electrical schematic symbols used to
designate components.
 Develop reverse engineering skills.
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Fundamentals of Engineering – Honors – ENGR H192
Product Analysis
Contents:
 Power Conversion and Approximation
 Schematic Components
 Motor Discussion
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Fundamentals of Engineering – Honors – ENGR H192
Power Conversion
watt [for James Watt], abbr. W, unit of power, or
work done per unit time, equal to 1 joule per
second. It is used as a measure of electrical and
mechanical power. One watt is the amount of
power that is delivered to a component of an
electric circuit when a current of 1 ampere flows
through the component and a voltage of 1 volt
exists across it.
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Fundamentals of Engineering – Honors – ENGR H192
Power Conversion
horsepower, unit of power in the English system of
units. It is equal to 33,000 foot-pounds per
minute or 550 foot-pounds per second or
approximately 746 watts. The term horsepower
originated with James Watt, who determined by
experiment that a horse could
do 33,000 foot-pounds of work
a minute in drawing coal from
a coal pit.
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Fundamentals of Engineering – Honors – ENGR H192
Schematic Symbols
Commonly Used Symbols:
DC Source
Resistor
N.C. Push
Button Switch
AC Source
Motor
Ground
Capacitor
Fuse
SPST Switch
N.O. Push
Button Switch
Female
Connector
Male
Connector
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Fundamentals of Engineering – Honors – ENGR H192
Part II
Shaded-Pole Motor Lecture
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Fundamentals of Engineering – Honors – ENGR H192
Breakaway View
Stator Winding
Rotor
Laminated Core
Poles “Shaded”
with Copper Wire
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Fundamentals of Engineering – Honors – ENGR H192
Shading Theory
Stator Winding
Shading
Coils
Rotor
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Fundamentals of Engineering – Honors – ENGR H192
Shading Theory
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Fundamentals of Engineering – Honors – ENGR H192
Shading Theory
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Fundamentals of Engineering – Honors – ENGR H192
Shading Segments
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Fundamentals of Engineering – Honors – ENGR H192
Flux Wave Rotation
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Fundamentals of Engineering – Honors – ENGR H192
Motor Speed
Motor theory tells us that the speed of an ac motor is
directly proportional to the frequency and inversely
proportional to the number of poles as follows:
120 fs
rpm =
Np
Thus, for a 2-pole motor running at 50 hz:
120 x 50
rpm =
= 3000
2
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Fundamentals of Engineering – Honors – ENGR H192
Motor Slip
The rotor of an induction motor will not rotate at the
theoretical speed due to slip. The equation for slip is:
rpmtheoretical  rpmactual
100  % slip
rpmtheoretical
Thus, if the anticipated rpm was 3600 and
the actual rpm was 3440:
3600  3440
 100  4.44% slip
3600
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