Lenze i700 - Manual (Page 153)

Lenze · i700 servo inverter · Reference manual · DMS 1.5 EN · 03/2014 · TD05
153
5 Motor control & motor settings
5.15 "DC-injection braking" function
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5.15 "DC-injection braking" function
The control modes for asynchronous motors provide the opportunity to use "DC-injection braking"
for the braking process.
DC-injection braking can be
• parameterised via bit 6 in the Lenze control word ( 0x2830 or 0x3030 for axis B) or
• as response to light errors.  Response of the device in the event of an error ( 262)
Cases of application
• for DC-injection braking via bit 6:
• The braking energy cannot be converted into heat in a brake resistor.
• An external control wants to request DC-injection braking with a drive in V/f operation.
• for DC-injection braking as response to light errors:
• Due to an encoder error, no quick stop is possible anymore.
Functional description
In this case, the motor control injects a DC current the amplitude of which can be set in the object
0x2B80 (or 0x3380 for axis B). For this purpose, it is required that the current control is adapted to
the corresponding motor.  Setting and optimising the current controller ( 105)
0x2B80 | 0x3380 - DC-injection braking: Current
Current amplitude for DC-injection braking
Note!
During the parameter setting of this object, it must be considered that a DC current amplitude is set here. In
contrast, the rated current of the motor is usually given as effective value. In order to prevent an overload of the
motor, the value set here should be at least lower by the factor "√2" than the rated motor current or attention
should be paid on a correspondingly set I²xt characteristic ( 0x2D4D or 0x354D for axis B).
Setting range (min. value | unit | max. value) Lenze setting
0.00 A 500.00 0.00 A
 Write access  CINH  OSC  P  RX  TX Scaling: 1/100 UNSIGNED_16

Note!
The r.m.s. value of the current is calculated from the time values by means of the use of
the factor "√2". This also happens in case of the field frequency 0 Hz (DC current). In case
of the DC injection braking, the r.m.s. value is thus given by the factor "√ too low in
0x2DD1:5 (or 0x35D1:5 for axis B).