Siemens MICROMASTER 411 - Manual (Page 146)

10 Engineering Information Issue 03/01
MICROMASTER 411 & COMBIMASTER 411 Operating Instructions
146 6SE6400-5CA00-0BP0
10.10 Use of MM4 Input Chokes
When the inverter is operating it gives rise to a non-sinusoidal current from the
mains supply with harmonics. The amplitude of the harmonics can be reduced by
fitting input chokes.
When the mains supply impedance is less then 1% it is necessary to use an input
choke with the inverter. It is recommended to use the standard MM4 range of input
chokes, details of which can be obtained from the DA51.2 Catalogue. The choke
must be housed in a mechanical enclosure appropriate to the environment.
10.10.1 Mains Supply Impedance
This is the ratio of the inverter rated power to mains short-circuit power. If the
mains supply impedance is below 1%, the lifetime of the electrolytic capacitors
could be reduced.
The mains short-circuit power may be obtained from the power supply company, or
may be read from the Type Plate of the supplying power transformer.
10.11 Power Losses
Figure 10-18 shows the power loss for the MICROMASTER 411/COMBIMASTER
411 Inverters.
88
90
92
94
96
98
0 5 10 15 20 25 30 35 40 45 50
Output Frequency
Effic
ienc
y
Hz
%
Efficiency at Max Line CSB
Efficiency at Min Line CSB
Efficiency at Max Line CSC
Efficiency at Min Line CSC
Figure 10-18 Power Losses MICROMASTER 411 / COMBIMASTER 411