Question:
How much is the time to trip of the 8200vector/motec's I²xt-monitoring?
Answer:
The 8200vector/motec frequency inverter offers the possibility to switch off the I²xt for sensor-less thermal motor monitoring of self-ventilated three-phase AC motors (no total motor protection!!!). For this purpose the required switch-off threshold can be set, where the I²xt monitoring intervenes. The setting of code C0120 is calculated as follows:
C0120 [%] = I rated motor current / I inverter * 100 %
I rated motor current = motor rated current
I inverter = inverter output rated current corresponding to the selected switching frequency
This value corresponds to 100 % motor utilization. If the value in code C0120 is reduced, the I²xt-monitoring is activated already when the motor utilization is < 100 %. If the value in code C0120 is increased, the I²xt-monitoring is activated not before the motor utilization is > 100 % (Attention: Motor protection is not ensured!!!).
By means of a nonlinear release the time to trip of the I²xt-switch off is calculated independent from the inverter's output rated current, the actual flowing apparent motor current (C0054), the current output frequency (C0050), as well as from the setting of code C0120 (I²xt-switch off).
The time to trip of the I²xt-monitoring can be calculated by means of the attachment.
