Device Overload Monitoring (I*T) - Lenze i950 Commissioning Manual

17.14

Device overload monitoring (i*t)

The inverter calculates the i*t utilisation in order to protect itself against thermal overload. In
simple terms: a higher current or an overcurrent that continues for a longer time causes a
higher i*t utilisation.
DANGER!
Uncontrolled motor movements by pulse inhibit.
When the device overload monitoring function is activated, pulse inhibit is set and the motor
becomes torqueless. A load that is connected to motors without a holding brake may there-
fore cause uncontrolled movements! Without a load, the motor will coast.
▶ Only operate the inverter under permissible load conditions.
Details
The device overload monitoring function primarily offers protection to the power section.
Indirectly, also other components such as filter chokes, circuit-board conductors, and termi-
nals are protected against overheating. Short-time overload currents followed by recovery
periods (times of smaller current utilisation) are permissible. The monitoring function during
operation checks whether these conditions are met, taking into consideration that higher
switching frequencies and lower stator frequencies as well as higher DC currents cause a
greater device utilisation.
If the total utilisation exceeds the total warning threshold set in
•
ting: 95 %), the inverter outputs a warning.
If the device utilisation exceeds the permanent error threshold 100 %, the inverter is disa-
•
bled immediately and generates an error message.
The device overload can be obtained from the configuration document.
•
Parameter
Address Name / setting range / [default setting]
0x2D40:001 Device utilisation ixt: Power unit actual utilisation
• Read only: x %
0x2D40:002 Device utilisation ixt: Power unit warning threshold
0 ... [95] ... 101 %
0x2D40:003 Device utilisation ixt: Power unit error threshold
• Read only: x %
0x2D40:004 Device utilisation ixt: Device actual utilisation
• Read only: x %
0x2D40:005 Device utilisation ixt: Device warning threshold
0 ... [95] ... 101 %
0x2D40:006 Device utilisation ixt: Device error threshold
• Read only: x %
0x2D40:007 Device utilisation ixt: Actual total utilisation
• Read only: x %
0x2D40:008 Device utilisation ixt: Total utilisation warning thresh-
old
0 ... [95] ... 101 %
0x2D40:009 Device utilisation ixt: Total utilisation error threshold
• Read only: x %
Device overload monitoring (i*t)
0x2D40:008 (default set-
Info
Display of the power module utilisation.
If the device utilisation exceeds the threshold set, the inverter outputs a
warning.
If the power module utilisation exceeds the displayed threshold, the
inverter outputs a warning.
Display of the current device utilisation.
If the device utilisation exceeds the displayed threshold, the device out-
puts an error.
Display of the current total device utilisation.
If the total utilisation exceeds the set threshold, the device outputs a
warning.
If the total utilisation exceeds the displayed threshold, the device out-
puts an error.
Device functions
359