Operating Instructions ACTIVE06/07 185
06/07 Operating Instructions ACTIVE 185
17.4 Brake Chopper and Brake Resistance
The frequency inverters feature a brake chopper transistor. The external brake resis-
tor is connected to terminals Rb1 and Rb2. The parameter
Trigger Threshold 506
defines the switch-on threshold of the brake chopper. The generator output of the
drive, which leads to the increase in the DC link voltage, is converted to heat by the
external brake resistor above the limit set via parameter
Trigger Threshold 506.
Parameter Settings
No. Description Min. Max. Fact. sett.
506 Trigger Threshold U
dmin
+25V 1000.0 V U
dBC
Default settings of parameter Trigger Threshold 506:
- 385 V for ACT series of devices ACT 201
- 770 V for ACT series of devices ACT 401
The parameter
Trigger Threshold 506 is to be set in such a way that it is between
the maximum DC link voltage which the mains can generate and the maximum admis-
sible DC link voltage of the frequency inverter.
maxBCNetz
UdUd21.1U <<⋅⋅
If the parameter
Trigger Threshold 506 is set larger than the maximum admissible
DC link voltage, the brake chopper cannot become active, the brake chopper is
switched off.
If the parameter Trigger Threshold 506 is set to a value below the DC link voltage
generated by the mains, error message F0705 (chapter "Error Messages") is displayed
if the start command is issued to the frequency inverter.
If the DC link voltage exceeds the maximum values of 400 V for the ACT 201 series of
devices and 800 V for the ACT 401 series of devices, respectively, error message
F0700 is displayed (chapter "Error Messages").
The sampling period of the function is 125 µs.
After exceeding the trigger threshold the brake chopper remains in switched-on condi-
tion for at least 125 µs, even if the DC link voltage will fall below the trigger threshold
in this time.
Brake chopper
ON
OFF
125 s
µ
t
U
d
Trigger Threshold
506
t
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