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Import of a Technical Question of a not registered user
Guest
Greetings:
Was searching through a thread concerning my subject matter "Active-line module vs Smart-line module" and came across the following:
hi
The advantages of the ALM are for example
- regulation at a 400V line up to 720 V DC link voltage (so you get more output voltage for your motors)
- power factor correction
- sine form of the current
- high stabilty at weak grids - for example constant DC- link although the line goes down to 50% line voltage
- master slave / redundancy at a common DC- link
VP


I have an issue/potential problem which speaks very much to the points as stated above.
I have a drive system for a double-end dynamometerwhich includes the following Siemens components:




Module ID

Module Description

Module Part Number

Module Options


LCM1

1000A Line Connection Module

6SL3700-0LE41-0AA3

D02+K76+L44+M23+M70+M82+Y11+X30


SLM1

518kW Smart Line Module

6SL3730-6TE41-1AA3

D02+K08+K91+M23+M82+Y11


MM1

710kW Motor Module

6SL3720-1TE41-2AA3

D02+K50+M23+M27+M70+M82+Y11


MM2

710kW Motor Module

6SL3720-1TE41-2AA3

D02+K50+M23+M26+M70+M82+Y11


ENG

Integration engineering

6SL3780-0AC00-0AA0

Options selected:
D02
Customer documentation (circuit diagram, terminal diagram, layout diagram) in DXF format
K08
AOP30 Advanced Operator Panel, door mounted
K50
SMC30 Sensor Module Cabinet-Mounted
K76
Auxiliary voltage supply, mounted in LCM
K91
Control Unit CU320 with associated CompactFlash card with performance enhancement 1
L44
Line Connection Module for Smart Line Modules
M23
IP23 Degree of protection
M26
Side panel (right)
M27
Side panel (left)
M70
EMC shield busbar
M82
DC busbar system (Id = 1840 A, 1x 100 x 10 mm)
Y11
Grouped assembly of Cabinet Modules into transport units
X30
Qty. 2 Blower Starters for motor blower
Based on measurements, it appears that DClink voltage is capped at about 650V, providing a cap of approximately 440-450 Vac to the e-motors. I am by no means so versed on this subject technically speaking, but colleagues who are so versed report that these observed "apparent" caps are a consequence of the SMART-line module, relative to the ACTIVE-line module, which should provide higher DClink voltage, from which my 480 V line-in would yield higher than 650Vdclink (based on measurements, I am confident that line voltage is nominally 480V). To provide 480V at e-motors from 3300rpm thru to 8000rpm top speed, my colleague tells me (based on his previous experiences with your drive system products) that approximately 700Vdclink would be required for rated performance, then even greater Vdclink for short duration 175% of rated excursions in this 7500-8000rpm range(e-motor rated condition 2000rpm/1675Nm....350KW......then holds 350KW through to 8000rpm). I realize this is quite a bit of information to put into this message, but would like to know whether I am truly limited by the presence of the SMART-line module, and"apparent" 650Vdclink top end, or can the SMART-line module provide additional Vdclink up to 720V as the Siemens drive system drawing notes. Thanks in advance for your reply.