Fundamental Principles and System Description
Engineering Information
1.14.2.6 Partial load efficiency of G130 / G150 converters
The charts below show the partial-load efficiency of SINAMICS G130 and G150 converters for constant-torque
drives. The calculations are based on a typical efficiency at full load of 98 %. The efficiency is represented in two
different ways. In one chart, the efficiency is shown as a function of the output frequency with the output current as a
parameter, and in the second chart, as a function of the output current with the output frequency as a parameter.
Figure 1a) shows the characteristic curve of the efficiency for constant-torque drives as a function of the output
frequency ratio f
/f
which is proportional to the motor speed ratio n/n
. The parameter for the family of
Out
Out-rated
rated
curves is the output current ratio I
/I
which is proportional to the motor torque ratio M/M
.
Out
Out-rated
rated
Figure 1a)
Efficiency of SINAMICS G130 and G150 converters in constant-torque drives
as a function of the output frequency ratio in %
Figure 1b) shows the characteristic curve of the efficiency for constant-torque drives as a function of the output
current ratio I
/I
which is proportional to the motor torque ratio M/M
. The parameter for the family of
Out
Out-rated
rated
curves is the output frequency ratio f
/f
which is proportional to the motor speed ratio n/n
.
Out
Out-rated
rated
Figure 1b)
Efficiency of SINAMICS G130 and G150 converters in constant-torque drives
as a function of the output current ratio in %
SINAMICS Engineering Manual – November 2015
187/528
Ó Siemens AG