Use of a brake resistor
For braking operation, optionally the brake chopper integrated in the inverter (brake transistor) can be used.
Preconditions
In order that the integrated brake chopper is activated in the braking operation, one of the following braking methods must be set in 0x2541:001 (P706.01):
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"Brake resistor [0]"
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"Brake resistor + RFGS [2]"
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"Brake resistor + IMB + RFGS [4]"
In the default setting of 0x2541:001 (P706.01), the integrated brake chopper is not activated in the brake operation!
Details
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The brake resistor required is to be connected to terminals RB1 and RB2 of the inverter.
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In 0x2541:001 (P706.01), additionally the stopping function for the deceleration ramp function generator can be set when the brake resistor is controlled, in order to avoid overvoltage disconnection in the case of lower deceleration times.
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In the default setting and with a disabled inverter and an error status ("Error active"), the brake chopper is switched off. This behaviour can be changed in 0x2541:006 (P706.06). Example: In a DC-bus connection with several inverters, only one brake resistor is used. It is connected to the most powerful inverter in the DC-bus connection. This inverter then serves to change the behaviour so that inverter disable and/or an error does not cause a switch-off of the brake chopper.
Internal protective function
The following protective function prevents the brake chopper from being switched on permanently, e.g. due to too high voltages or wrong settings:
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The brake chopper is switched off if it was switched on over a period of 4 s.
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If the DC-bus voltage again falls below the voltage threshold for braking operation, the brake chopper can again be switched on for maximally 4 s without interruption.
Brake resistor monitoring
The inverter calculates and monitors the thermal load of the brake resistor to ensure that the brake resistor will not be overloaded.
A correct calculation required the following settings according to the data on the nameplate of the brake resistor:
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0x2550:002 (P707.02): Resistance value
–
0x2550:003 (P707.03): Rated power
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0x2550:004 (P707.04): Maximum thermal load
The calculated thermal load is not displayed in 0x2550:007 (P707.07).
The brake resistor monitoring is designed with two stages:
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If the calculated thermal load exceeds the warning threshold set in 0x2550:008 (P707.08) (default setting: 90 %), the response set in 0x2550:010 (P707.10) takes place (default setting: "Warning"). The warning status will be reset if the thermal load falls below the warning threshold - 20 %.
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If the calculated thermal load exceeds the warning threshold set in 0x2550:009 (P707.09) (default setting: 100 %), the response set in 0x2550:011 (P707.11) takes place (default setting: "Fault"). The error status will be reset if the thermal load falls below the error threshold - 20 %.
Parameter
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Address
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Name / setting range / [default setting]
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Information
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|
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0x2541:006
(P706.06)
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Brake energy management: Brake resistor response
(Brake management: Brk. res. behav)
–
Setting can only be changed if the inverter is disabled.
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Behaviour of the integrated brake chopper if the inverter is disabled and if the error status is active.
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|
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0
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Off: disable / Off: error
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If the inverter is disabled and the error status is active, the brake chopper is switched off.
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|
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1
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On: disable / off: error
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Brake chopper is switched off if the error status is active, but not if the inverter is disabled.
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2
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Off: disable / on: error
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Brake chopper is switched off if the inverter is disabled but not if the error status is active.
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|
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3
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On: disable / On: error
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Brake chopper is not switched off if the inverter disabled and the error status is active.
|
|
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0x2550:002
(P707.02)
|
Brake resistor: Resistance value
(Brake resistor: Resistance value)
0.0 ... [180.0]* ... 500.0 Ω
* Default setting dependent on the model.
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Resistance value of the brake resistor connected.
–
The value to be entered can be obtained from the brake resistor nameplate.
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|
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0x2550:003
(P707.03)
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Brake resistor: Rated power
(Brake resistor: Rated power)
0 ... [50]* ... 800000 W
* Default setting dependent on the model.
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Rated power of the brake resistor connected.
–
The value to be entered can be obtained from the brake resistor nameplate.
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|
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0x2550:004
(P707.04)
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Brake resistor: Maximum thermal load
(Brake resistor: Maximum heat)
0.0 ... [8.0]* ... 100000.0 kWs
* Default setting dependent on the model.
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Thermal capacity of the brake resistor connected.
–
The value to be entered can be obtained from the brake resistor nameplate.
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|
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0x2550:007
(P707.07)
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Brake resistor: Thermal load
(Brake resistor: Thermal load)
–
Read only: x.x %
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Display of the utilisation of the brake resistor connected.
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0x2550:008
(P707.08)
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Brake resistor: Warning threshold
(Brake resistor: Warning thresh.)
50.0 ... [90.0] ... 150.0 %
|
Warning threshold for brake resistor monitoring.
–
If the utilisation shown in 0x2541:004 (P706.04) reaches the threshold set, the response selected in 0x2550:010 (P707.10) is effected.
–
The warning is reset with a hysteresis of 20 %.
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|
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0x2550:009
(P707.09)
|
Brake resistor: Error threshold
(Brake resistor: Error thresh.)
50.0 ... [100.0] ... 150.0 %
|
Error threshold for brake resistor monitoring.
–
If the utilisation shown in 0x2541:004 (P706.04) reaches the threshold set, the response selected in 0x2550:011 (P707.11) is effected.
–
Resetting the error is only possible if the hysteresis is lower than 20 %.
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0x2550:010
(P707.10)
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Brake resistor: Response to warning
(Brake resistor: Warning resp.)
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Selection of the response that is executed when the warning threshold for brake resistor monitoring is reached.
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0
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No response
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1
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Warning
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2
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Trouble
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3
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Fault
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0x2550:011
(P707.11)
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Brake resistor: Response to error
(Brake resistor: Error response)
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Selection of the response to be executed when the error threshold for brake resistor monitoring is reached.
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0
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No response
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1
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Warning
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2
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Trouble
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3
|
Fault
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Severity