Programming instructions

DC Motor
 National Instruments Corporation 13-3 Multisim Component Reference Guide
13.2.1 Characteristic Equations
The characteristic equations of an ideal DC motor are given by:
where:
ω
m
= rotational speed
K
m
= EMF constant
V
a
= armature voltage
V
f
= field voltage
Other terms are defined in “DC Motor Parameters and Defaults”.
The EMF constant K
m
is determined by:
VRiL
di
dt
Ki
VRi L
di
dt
J
d
dt
BTKii
aaaa
a
mf m
f
ff f
f
m
fmL mf
a
=∗+ + ∗∗
=∗+
+∗ += ∗∗
ω
ω
ω
K
VIR
I
n
I
V
R
I
V
R
V
R
I
V
R
I
m
aN a
N
a
fN
N
fN
fN
f
fN
fN
f
aN
f
fN
fN
f
aN
=
−∗
∗
=
=
=
2
60
π *
where
=
=
for separately excited DC motor
for parallel excited DC motor
for series excited DC motor
ComponentRef.book Page 3 Thursday, December 7, 2006 10:12 AM