HEIDENHAIN ITNC 530 - I 2 T Monitoring

3 – 676 HEIDENHAIN Service Manual iTNC 530
3.3.9 I
2
t monitoring
General
information
HEIDENHAIN inverter systems feature individual I
2
t monitors, one for each power module and
motor.
Function An I
2
t monitor calculates and supervises the temperature pattern in a thermal motor or power-
stage model during operation.
The calculation is based on:
 The momentary current
 The rated or standstill current
(with motors multiplied by MP 2302.x and with power stages multiplied by MP 2304.x)
 A device-specific temperature model
A first-order temperature model is available for monitoring power modules, first and second-
order models are available for motors. These models make it possible to permanently calculate
the temperature of the stator winding in the motor or the semiconductor in the power module.
Temperature model in an example comparison (motor)
The I
2
t monitor responds if this calculated temperature exceeds a certain limit.
Because temperature increase and heat dissipation are uneven when the motor is stationary or
moving slowly, the I
2
t monitor distinguishes between standstill and traversing mode.
This limit range is defined in a motor table or power module table.
The following entries are important:
 F-AC (transition frequency in traversing mode [Hz])
 F-DC (transition frequency at standstill [Hz]; only CC 424(B))
0 100 200 300 400 500 600 700 800 900 1 000
0
2020
40
60
80
100
120
140
160
180
200
T [°C]
Motor temperature
Second-order temperature model
First-order temperature model
t [s]