Search

Premium Membership ❱❱

Study specialized electrical engineering articles and technical papers in low/high voltage areas. Save 15% on PRO plan with code EEP21.

Formulas

Shunt Generator
For a shunt generator with armature induced voltage Ea, armature current Ia and armature resistance Ra, the terminal voltage V is:
V = Ea – IaRa
The field current I f for a field resistance R f is:
I f = V / R f

The armature induced voltage Ea and torque T with magnetic flux F at angular speed w are:
Ea = k fFw = kmw
T = k fFIa = kmIa
where k f and km are design coefficients of the machine.

Note that for a shunt generator:
– induced voltage is proportional to speed,
– torque is proportional to armature current.

The airgap power Pe for a shunt generator is:
Pe = wT = EaIa = kmw Ia

Shunt Motor
For a shunt motor with armature induced voltage Ea, armature current Ia and armature resistance Ra, the terminal voltage V is:
V = Ea + IaRa
The field current I f for a field resistance R f is:
I f = V / R f

The armature induced voltage Ea and torque T with magnetic flux F at angular speed w are:
Ea = k fFw = kmw
T = k fFIa = kmIa
where k f and km are design coefficients of the machine.

Note that for a shunt motor:
– induced voltage is proportional to speed,
– torque is proportional to armature current.

The airgap power Pe for a shunt motor is:
Pe = wT = EaIa = kmw Ia

Series Motor
For a series motor with armature induced voltage Ea, armature current Ia, armature resistance Ra and field resistance R f, the terminal voltage V is:
V = Ea + IaRa + IaR f = Ea + Ia(Ra + R f)
The field current is equal to the armature current.

The armature induced voltage Ea and torque T with magnetic flux F at angular speed w are:
Ea = k fFw Ia = kmw Ia
T = k fFIa2 = kmIa2
where k f and km are design coefficients of the machine.

Note that for a series motor:
– induced voltage is proportional to both speed and armature current,
– torque is proportional to the square of armature current,
– armature current is inversely proportional to speed for a constant induced voltage.

The airgap power Pe for a series motor is:
Pe = wT = EaIa = kmw Ia2

NOTATION
The symbol font is used for some notation and formulae. If the Greek symbols for alpha beta delta do not appear here [ a b d ] the symbol font needs to be installed for correct display of notation and formulae.
B
E
f
G
I
j
k
m
N
n
P
p
R
susceptance
induced voltage
frequency
conductance
current
j-operator
coefficient
number of phases
number of turns
rotational speed
power
pole pairs
resistance
[siemens, S]
[volts, V]
[hertz, Hz]
[siemens, S]
[amps, A]
[1Ð90°]
[number]
[number]
[number]
[revs/min]
[watts, W]
[number]
[ohms, W]
S
s
T
V
X
Y
Z
d
F
f
h
q
w
voltamperes
slip
torque
terminal voltage
reactance
admittance
impedance
loss angle
magnetic flux
phase angle
efficiency
temperature
angular speed
[volt-amps, VA]
[per-unit]
[newton-metres, Nm]
[volts, V]
[ohms, W]
[siemens, S]
[ohms, W]
[degrees, °]
[webers, Wb]
[degrees, °]
[per-unit]
[centigrade, °C]
[radians/sec]

Premium Membership

Get access to premium HV/MV/LV technical articles, advanced electrical engineering guides, papers, and much more! It will help you to shape up your technical skills in your everyday life as an electrical engineer.
More Information

Leave a Comment

Tell us what you're thinking... we care about your opinion! Please keep in mind that comments are moderated and rel="nofollow" is in use. So, please do not use a spammy keyword or a domain as your name, or it will be deleted. Let's have a professional and meaningful conversation instead. Thanks for dropping by!

  ×  9  =  fifty four

Learn to Design Power Systems

Learn to design LV/MV/HV power systems through professional video courses. Lifetime access. Enjoy learning!

Subscribe to Newsletter

Subscribe to our Weekly Digest newsletter and receive free updates on new technical articles, video courses and electrical guides.