User Manual

Table Of Contents
Induction Motor Parameters Calculation
Advanced Digital Motor Controller User Manual 143
Example:
The following data have been given from the induction motor manufacturer:
P = 400 W (nominal power)
I
N
= 23 A (nominal stator current)
V
dc
= 24 V (Input dc voltage at controller)
f
s
= 90 Hz (Nominal stator frequency)
n
s
= 2700 rpm (Synchronous speed)
p= 2 (pole pairs)
Therefore, the Volts per Hertz ratio introduced in configuration tab is
V
f
=
24
90
=0.267
dc
s
Then the motor run volts per Hertz and the respective results from Roborun+ utility are
illustrated below.
FIGURE 9-10. No load testing monitoring
From the above results, it can been observed that the stator speed is close to the syn-
chronous speed (2700 rpm), while the slip is very small due to the no-load operation.
Therefore, by applying equation (9.1) the magnetizing inductance is:
L
V
2fI
24.1
32
290 23.1
754uH
m
s
s
== =


Furthermore, the rotor “Rotor Flux current” should be set in the configuration as (Motor
Amps) x
2
= 32.7 A