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ECET 211 Electric Machines and Controls
Fundamental Units
Professor Paul I-Hai Lin
Department of Computer, Electrical and Information Technology
Indiana University-Purdue University Fort Wayne
Basic SI Units
 Mass
Kilogram (kg)
1 kg = 2.205 pounds
1 pound (lb) = 0.4536 kg
1 oz = 0.02835 kg = 28.35 g
 Length
Meter (m)
1 m = 100 cm = 1000 mm = 39.27 inches
1 inch = 25.4 cm
 Temperature
Three temperature scales: Celsius, Fahrenheit, and Kelvin
 Electric current
ampere: A
 Thermodynamic temperature
Kelvin: K
 Amount of substance
Mole: mol
 Luminous intensity
Candela: cd
Fahrenheit
The degree Fahrenheit (°F) non-metric temperature scale was devised and
evolved over time so that the freezing and boiling temperatures of water are
whole numbers, but not round numbers as in the Celsius temperature scale.
Celsius
The degree Celsius (°C) scale was devised by dividing the range of temperature
between the freezing and boiling temperatures of pure water at standard
atmospheric conditions (sea level pressure) into 100 equal parts. Temperatures
on this scale were at one time known as degrees centigrade, however it is no
longer (since 1948 when the official name was change) correct to use that
terminology.
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Kelvin
The Kelvin (K) temperature scale is an extension of the degree Celsius scale
down to absolute zero, a hypothetical temperature characterized by a complete
absence of heat energy. Temperatures on this scale are called Kelvin, NOT
degrees Kelvin, Kelvin is not capitalized, and the symbol (capital K) stands alone
with no degree symbol.
Water Boiling Point Temp
Water Freezing Temperature
Absolute Zero
373.15 k, 100 C, 212 F
273.15 k, 0 C, 32 F
0 k, -273.15 C, -459.57 F
Temperature
Kelvins
degrees Celsius
degrees Fahrenheit
Symbol
K
°C
°F
Boiling point of water
373.15
100.
212.
Freezing / melting point of water / ice
273.15
0.
32.
Absolute zero
0.
-273.15
-459.67
Temperature Conversion Formulas
 Kelvin = C + 273.15
 degree F = C (9/5) + 32
 degree C = (F – 32)/1.8
SI Derived Units
Frequency
hertz: Hz = 1/s
Force
newton: N = m kg/s2
Pressure, stress
pascal: Pa = N/m2 = kg/m s2
Energy, work, quantity of heat
joule: J = N m = m2 kg/s2
Power, radiant flux
Watt: W = Joule/sec = m2 kg/s3
Quantity of electricity, electric charge
coulomb: C = sec* Ampere
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Electric potential
volt: V = Watt/Ampere = m2 kg/s3 A
Capacitance
farad: F = Coulomb/Volt = s4 A2/m2 kg
Electric resistance
ohm: Omega = Volt/Ampere = m2 kg/s3 A2
Conductance
siemens: S = A/V = s3 A2/m2 kg
Magnetic flux
weber: Wb = V s = m2 kg/s2 A
Magnetic flux density, magnetic induction
tesla: T = Wb/m2 = kg/s2 A
Inductance
henry: H = Wb/A = m2 kg/s2 A2
Luminous flux
lumen: lm = cd sr
Illuminance
lux: lx = lm/m2 = cd sr/m2
Activity (ionizing radiations)
becquerel: Bq = 1/s
Absorbed dose
gray: Gy = J/kg = m2/s2
Dynamic viscosity
pascal second: Pa s = kg/m s
Moment of force
meter newton: N m = m2 kg/s2
Surface tension
newton per meter: N/m = kg/s2
Heat flux density, irradiance
watt per square meter: W/m2 = kg/s3
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Heat capacity, entropy
joule per kelvin: J/K = m2 kg/s2 K
Specific heat capacity, specific entropy
joule per kilogram kelvin: J/kg K = m2/s2 K
Specific energy
joule per kilogram: J/kg = m2/s2
Thermal conductivity
watt per meter kelvin: W/m K = m kg/s3 K
Energy density
joule per cubic meter: J/m3 = kg/m s2
Electric field strength
volt per meter: V/m = m kg/s3 A
Electric charge density
coulomb per cubic meter: C/m3 = s A/m3
Electric displacement, electric flux density
coulomb per square meter: C/m2 = s A/m2
Permittivity
farad per meter: F/m = s4 A2/m3 kg
Permeability
henry per meter: H/m = m kg/s2 A2
Molar energy
joule per mole: J/mol = m2 kg/s2 mol
Molar entropy, molar heat capacity
joule per mole kelvin: J/mol K = m2 kg/s2 K mol
Exposure (ionizing radiations)
coulomb per kilogram: C/kg = s A/kg
Absorbed dose rate
gray per second: Gy/s = m2/s3
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Electricity
Electrical Charge
Unit: Coulomb
1 Electron = 1.6 x 10-19 Coulombs
1 C = 6.24 x 1018 electrons
1 C = 1 Amp-second
Charles Augustin de Coulomb (1736-1806), France,
http://en.wikipedia.org/wiki/Charles-Augustin_de_Coulomb
Coulomb’s Law describes forces between two charged particles
q q
F k a b
r
Attractive force (negative sign) or repulsive force (positive sign)
r is distance between two particles
k = 8.99 x 109 Nm2/C2
Static generator (electricity)
 High voltage DC
 Energy = ½ QV2
 Clouds are charged by rubbing together
 Friction causes static charge
 Electric shocks:
o Body voltage when getting out of a car
 Nylon clothes: 21,000 volts
 Wool clothes: 9,000 volts
 Cotton clothes: 7,000 volts
o In office
 Charge generators (static electric machines)
 Charge detectors
 Charge eliminators
o Industrial static control
o Ionizer air gun, curtain
 Storage of charges
o Capacitors
Electrical Units
 Current (I, ampere, A)
 Electromotive Force (E, volt, V)
 Potential Difference (V, volt, V)
 Resistance (R, ohm, )
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Electrical Current
Ampere, I
Ammeter, A
AC, DC
Example
Potential
Volt, E
Voltmeter, V
1.5, 9, 12, 24, 115, 220, 230, 460, 575, 2300, 765kv
AC, DC
Example
Resistance
Resistors
Ohms
Ohmmeter
Static
Dynamic
Temperature sensitive
Example
Watts
P = V*I
P = V^2/R
P = I^2*R
P = V * I * cos(theta)
P = 1.732 * V * I * cos(theta)
Horse Power (HP)
1 HP = 746 Watts
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Number Prefix Used with Electrical/Electronic Units
Prefix
Symbol
Factor
Yotta
Zetta
Exa
Peta
Tera
Giga
Mega
Kilo
hecto
deca
deci
centi
milli
micro
nano
pico
femto
atto
zepto
yocto
Y
Z
E
P
T
G
M
k
h
da
d
c
m

n
p
f
a
z
y
1024
1021
1018
1015
1012
109
106
103
102
101
10-1
10-2
10-3
10-6
10-9
10-12
10-15
10-18
10-21
10-24
or E24
or E21
or E18
or E15
or E12
or E9
or E6
or E3
or E2
or E1
or E-1
or E-2
or E-3
or E-6
or E-9
or E-12
or E-15
or E-18
or E-21
or E-24
Electrical Materials
 Conductor
 Insulator
 Semiconductor
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Web Site References
 SI units (the International System of Units)
o International Systems of Units from National Institute of Standards
and Technology: http://physics.nist.gov/cuu/Units/index.html
o Institute of Chemistry: http://www.chemie.fuberlin.de/chemistry/general/si_en.html
o Basic and Derived SI Units: http://www.techexpo.com/techdata/siunits.html
o Bureau International des Poids et Mesures:
http://www.bipm.fr/enus/3_SI/si.html
 Electricity
o Static Electricity Page: http://www.electricalcontractor.net/ESF/Static%20Electricity%20Page.htm
o Electrostatic Electricity generator:
http://www.sparkmuseum.com/FRICTION.HTM (machine pictures)
o How does static electricity work? The Library of Congress,
http://www.loc.gov/rr/scitech/mysteries/static.html
o Static Electricity, by Science Made Simple,
http://www.sciencemadesimple.com/static.html
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