January 2012 6.17 Monitoring Functions 977
6.17.9 Momentary utilization of drive motors
Module 9166 provides the momentary utilization of the given drive motor as a
percentage value.
Utilization means:
Instead of the drive torque, one uses the effective component I
q
of the
current, which is proportional to the torque.
I
qMean
is formed as mean value of the individual current values I
qx
of the last
20 ms:
For asynchronous motors:
I
N
: Rated current of motor
I
mag
: Magnetizing current
For synchronous motors:
I
qRated
= <Rated current of motor>
The utilization display of synchronous motors is with respect to the rated
torque (M/M
rated
).
Speed range n
actl
< rated speed n
actl
Š rated speed
Asynchronous
motor
Synchronous motor –
M
M
Mean
------------------------
P
P
Mean
----------------------
M
M
Mean
------------------------
I
qMean
I
q1
..I
qn
()
∑
n
------------------------------=
Utilization 1000
I
qMean
I
qRated
-------------------
⋅=