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MCL Ironless Linear Motors
Determining the required addition‐
al DC bus capacity
●
either an interruption-free power supply or
●
additional DC bus capacities (capacitors), and /or
●
mechanical braking facilities
must be provided.
Additional capacities in the DC bus represent an additional energy store that
can supply the brake energy required in the event of a power outage.
The control voltage must be available even at a power failure for
the time of braking! If needed, buffer the control voltage supply or
feed the control voltage from the DC intermediate circuit if possi‐
ble!
The additional capacity required for a deactivation upon a mains failure can
be determined as follows:
C
Required additional DC bus capacitor in mF
add
m
Moved mass in kg
v
Maximum velocity in m/s
max
U
Maximum DC bus voltage in V
DCmax
U
Minimum DC bus voltage in V
DCmin
F
Maximum braking force of the motor in N
max
k
Motor constant (force constant) in N/A
FN
R
Winding resistance at 20 °C
12
F
Friction force in N
R
Fig. 9-30:
Determining the required additional DC bus capacitor
Prerequisites:
- final velocity = 0
- velocity-independent friction
- constant deceleration
- winding temperature 135 °C
The maximum possible DC bus capacity of the employed power
supply module must be taken into account when additional ca‐
pacities are used in the DC bus. Do not initiate a DC voltage
short-circuit when additional capacitors are employed.
Application and construction instructions
R911330592_Edition 06 Bosch Rexroth AG
127/197
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