3 i2t utilisation - brake resistor, I2t utilisation - brake resistor, I2t utilisation – Lenze 9400 User Manual
Page 270: Brake resistor, 7braking operation
7
Braking operation
7.2
Monitoring
270
Lenze · Servo-Inverter 9400 HighLine · Reference manual · DMS 10.0 EN · 11/2013 · TD05/06
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7.2.3
I2t utilisation - brake resistor
The controller is provided with a monitoring function of the I
2
t utilisation of the brake resistor
which is proportional to the converted braking power.
[7-2]
Signal flow - I2t utilisation - brake resistor
• The monitoring function is based on the mathematical model which calculates the braking
current from the current DC-bus voltage and the brake resistance parameterised in
• Hence, monitoring can be activated although no brake resistor is connected and can
therefore also be used for a testing mode to check the parameterisation.
• During the calculation, the thermal utilisation of the brake resistor on the basis of the following
parameters is taken into consideration:
• Resistance value (
)
• Continuous power (
)
• Thermal capacity (
•
displays the calculated utilisation of the brake resistor in [%].
• A 100 % utilisation corresponds to the continuous power of the brake resistor which results
at the maximum permissible temperature limit of the brake resistor.
• The calculated utilisation is provided as oscilloscope signal Common.dnI2tBrakeResistor to
check the braking operation while the system is running
(scaling: 2
30
≡ 100 %).
• If the utilisation exceeds the advance warning threshold set in
, "Brake resistor: I2t >
C00572" is entered in the logbook and the response set in
is activated.
Note!
If the DC-bus voltage exceeds the overvoltage threshold due to a too high braking
energy, the monitoring function for overvoltage in the DC bus responds.
Note!
The braking operation will never be switched off by this monitoring function.
I2t
C00138
C00129
T
= 0
Off
T
= 1
On
100 %
C00572
C00571
C00574
C00129
C00130
C00131
Logbook entry "
"
Brake resistor: I2t > C00572
Logbook entry "
"
Brake resistor: I2t overload
U
DC_act
Temperature model
I
=
Br
I
Br