U
Mv
Voltage value at frequency fv
U
Gv
Voltage limit value for frequency fv
ΔT
ges
Calculated temperature rise of the dielectric for all frequencies
Fig.15-45:
Calculating the Temperature Rise of the Dielectric for all Frequencies
With the above formulas and the measured voltages, it is possible to deter‐
mine the real load of a filter with voltages of higher frequencies. To this end,
the rms value of the voltage on the mains side of the filter with all occurring
frequencies (higher than f
k
) must be measured by means of a Fourier analy‐
sis for all combinations of line/line and line/PE. You always have to measure
the voltages under conditions of operation at the nominal working point, the
filter having been installed. By means of the measured values, it is then pos‐
sible to calculate the temperature rise. To do this, the limit values of the fol‐
lowing diagram are read at the respective frequency and used in the formula
together with the measured value.
L / L
Line / line
L / PE
Line / PE
Fig.15-46:
Derating
If the total of the temperature values is greater than 10 K, the harmonics have
to be reduced by means of appropriate measures.
Current Reduction in the Case of Overtemperature
The mains filters recommended by Rexroth have been sized for an ambient
temperature of 45 °C.
For higher temperatures, reduce the mains current according to the following
formula:
Bosch Rexroth AG
DOK-INDRV*-SYSTEM*****-PR06-EN-P
Rexroth IndraDrive Drive Systems with HMV01/02 HMS01/02, HMD01, HCS02/03
274/309
Calculations
