8monitoring functions – Lenze i700 User Manual
Page 244
8
Monitoring functions
8.4
Monitoring of the motor utilisation (I²xt)
244
Lenze · i700 servo inverter · Reference manual · DMS 1.5 EN · 03/2014 · TD05
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Parameter setting of the time constant and the influence of the winding on motors of other
manufacturers
When the influence of the winding is activated, the i²xt monitoring becomes more sensible as if only
the influence of the laminated core would be used for monitoring purposes.
The necessity to activate the influence of the winding rises with the increasing utilisation of the
motor overload capacity. It also rises with applications where the motor is at standstill for longer
periods or cyclically and a load ≥ permanent standstill current is applied.
For determining the values for the thermal time constant, try to get the data from the motor
manufacturer. If this is not possible, you can use the data of a comparable Lenze motor.
Conditions for comparability are similar values in case of the following motor features:
• Square dimensions of the motor (active part)
• Length of the active part (if available)
• Permanent standstill current Io [A_RMS]
• Peak current/overload capacity [A_RMS]
• Copper resistance of the winding at 20 °C [Rphase]
Example:
When the "MCS09F38" Lenze motor is selected from the motor catalogue of the »PLC Designer«m
the following values are displayed:
• Thermal time constant of the winding = 126 s
(or
for axis B)
• Influence of the winding = 27 %
(or
for axis B)
Motor features
Data of the third-party
motor
Data of a comparable Lenze motor (from motor
catalogue)
Square dimension
95 mm
MCS09xxx = 89 mm
Standstill current
2.2 A
MCS09F38 = 3.0 A
Peak current
7.3 A
MCS09F38 = 15 A
Phase resistance
5.1 Ohm
MCS09F38 = 5.2 Ohm