Specifications

93
• DOK-DIAX01-MAIN+2AD+1M-ANW1-EN-E1,44 • 07.97
3. Controller Functions
Para-NOT-AUS
Parameter protocol !
☞
Parameter
A06
Designation
FUNCT 2
Function
Ramp active with E-Stop also
Value range or value
< 32 >
Figure 94: Parameters to activate speed comand value ramps with E-Stop due to
mains failure
3.19 Performance during mains failure (RAC)
To prevent the main spindle from coasting during a mains failure, the
RAC control unit can also brake the asynchronous drive. This is done
either at maximum or at approximately 1/5th of maximum braking torque
with so-called direct-current braking.
DC braking
The energy regenerated during braking is converted into heat in the rotor
of the motor. The braking time is approximately five times longer than that
of controlled braking at maximum braking torque, but is adequate for
many main spindle applications.
The permissible amount of braking energy depends on the size of the
motor. Braking the load moment of inertia of the rotor from N
max
increases
the rotor temperature by about 2K (
o
C). Additional moments of inertia
increase the temperature-rise linearly.
When the motor is at operating temperature, the temperature-rise should
not be more than 20K. This otherwise affects bearing service life. When
idling, the thermal recovery time is about 30 minutes.
DC braking is included in the standard control unit and is activated in the
standard parameter record.
Braking at maximum torque (RAC 2 and 3 only)
The energy regenerated in the RAC during braking is converted into heat
via a load resistor (additional bleeder). Due to short deceleration distances
and times, this type of braking is advantageous in servo applications. The
deceleration time is the same as in regenerative braking. The permissible
amount of energy depends on the controller:
RAC 3.1 120 kWs
RAC 2.2 240 kWs
Maximum-torque braking is only possible in the RAC 2.2 and 3.1 with the
"additional bleeder" option (type code field = Z1)!
An additional bleeder cannot be integrated into the RAC 4.1!