User Manual 08/2003 Edition

2
2 Installing and Connecting–up 02.99 05.03
2.2 Electrical system requirements
Regenerative
feedback
protection for
48 V supply (300 W
motor)
SITOP modular
48 V
2-36
L+
M
or
Depending on the type of power supply, the following possibilities are
available to provide regenerative feedback protection when the motors
brake:
Non–regulated 48 V power supply (transformer, rectifier)
The regenerative feedback protection depends on the following factors:
Effective total moment of inertia
Coincidence factor
Power supply used (output rating)
Regulated 48 V power supply (SITOP power)
Regenerative feedback protection with diode and capacitor
An example is shown in Fig. 2-11 where up to 3 drives can be operated
under the following conditions:
– Effective overall moment of inertia = motor moment of inertia
– Coincidence factor = 1
– Braking from rated speed in S3 duty
2 SITOP power
24 V
L+
M
Diode (adapt the current load capacity
to SITOP, if required, use a heatsink)
48 V
to the
remaining
system
M SIMODRIVE
Elko POSMO A, 1
15000 µF / 100 V
Fig. 2-11 Example: Regenerative feedback protection with diode and capacitor
SIMODRIVE
POSMO A, 3
Regenerative feedback protection with Power Management Module
48 V DC (DC-PMM/48V)
1 DC-PMM/48V can absorb a braking energy of 15 Ws.
Example:
– 3 motors each with a braking energy = 4.5 Ws
– Max. current load capability = 25 A
– Coincidence factor = 1
––> A maximum of 3 POSMO A –300 W can be connected to
1 DC–PMM/48V.
(at the rated motor current = 5.25 A, refer to Table 2-7 as a
result of the maximum braking energy of 15 Ws)
Siemens AG 2003 All rights reserved
SIMODRIVE POSMO A User Manual (POS1) – 08.03 Edition