Hitachi L700 Series

Chapter 4 Explanation of Functions
4 - 46
4.2.37 Dynamic braking (BRD) function
The dynamic braking (BRD) function is provided in the
L700-300LFF/HFF and other models that have the built-in BRD circuit.
With this function, the energy regenerated by the motor is consumed by
an external resistor (i.e., the energy is converted to heat). You can
effectively use this function in your system, for example, to operate the
motor as a generator by rapidly decelerating the motor.
To use this function, make the following settings:
Item Function code Data or range of data Description
Dynamic braking
usage ratio
b090 (*2)
0.0 Disabling the BRD operation
0.1 to 100.0 (%)
Setting of the dynamic braking usage ratio in units
of 0.1%
The inverter will trip when the set rate is exceeded.
Usage rate (%) = × 100
Dynamic braking
control
b095
00 Disabling the BRD operation
01
Enabling the BRD operation while the motor is
running
Disabling the BRD operation while the motor is
stopped
02
Enabling the BRD operation regardless of whether
the motor is running
Dynamic braking
activation level
b096
330 to 380 (V) (*1) Level setting for 200 V class models
660 to 760 (V) (*1) Level setting for 400 V class models
*1 The set dynamic braking activation level specifies the DC output voltage of the inverter's internal
converter.
*2 Please refer P2-22 for minimum resistance of connectable resistor and BRD ratio (2.2.5).
4.2.38 Cooling-fan operation setting
The cooling-fan operation setting function allows you to specify the
operation mode of the inverter's internal cooling fan. The cooling fan can
be operated on a constant basis or only while the inverter is driving the
motor.
Item Function code Data or range of data Description
Cooling fan
control
b092
00 Specifying that the fan operates on a constant basis
01
Specifying that the fan operates only while the
inverter is driving the motor.
Note that the fan operates for 5 minutes after the
inverter power is turned on and after the inverter is
stopped.
Note: The cooling fan stops automatically when instantaneous power failure occurs or the inverter power is
shut off and resume the operation after power recovered.
b090: Dynamic braking usage ratio
b095: Dynamic braking control
b096: Dynamic braking activation level
Related code
t2
ON
t1 t3
ON ON
BRD
operation
100 seconds
100 seconds
(t1+t2+t3)
b092: Cooling fan control
Related code