EE Pro for TI-89, 92 Plus
Equations - Motors and Generators
136
Pme
p
m
s
Pma
= ⋅ ⋅
⋅
3
2
ω
ω
Eq. 31.10.6
Pme
T
m
= ⋅
ω
Eq. 31.10.7
The eighth equation expresses torque in terms of p, Pma, and
ω
ω
s.
T
p Pma
s
= ⋅ ⋅
3
2
ω
Eq. 31.10.8
The last three equations show an equivalent circuit representation of induction motor action and links the power Pa
with rotor resistance Rr, rotor current Ir, slip s, rotor resistance per phase RR1 and the machine constant KM.
Pma
Rr Ir
s
s
Rr Ir
=
⋅
+ − ⋅
⋅
2
2
1
Eq. 31.10.9
Pa
s
s
Rr Ir
= − ⋅
⋅
1
2
Eq. 31.10.10
Rr
RR
KM
=
1
2
Eq. 31.10.11
Example
31.10
– Find the mechanical power for an induction motor with a slip of 0.95, a rotor current of 75 A ,
and a resistance of 1.8
Ω
.
Entered Values
Calculated Results
Solution
- Choose the next to last equation to compute the solution. Select by highlighting and pressing
¸
. Press
„
to display the input screen, enter all the known variables and press
„
to solve the
equation.
-PQYP8CTKCDNGU
+T
A#4TA
Ω
U
%QORWVGF4GUWNV
2C
A9
31.11 Induction Motor II
These equations are used to perform equivalent circuit analysis of an induction motor. The first equation shows the
power in the rotor per phase Pma, defined in terms of the rotor current Ir, rotor resistance Rr, and slip s.