Technical data and dimension diagrams
Operating instructions RHF
29
ELTROPLAN
-
REVCON
Elektrotechnische Anlagen GmbH
6 Selection of the right filter module and technical data
To reach optimal performance of the filter module and to operate it durable opti-
mal, the filter module must be sized so that it fits to the load defined by the line in-
put current of the frequency converter
=> I
FC,L
This is the input current of the frequency converter,
not
to be confused with the
classification of the frequency converter which is the output(motor) current of the
frequency converter.
6.1 Calculation
The line input current I
FC,L
can be calculated with the data of the motor, nominal
current I
M,N
and cos
φ
. Both data are to be found for example on the name plate of
the motor.
In the case that the nominal motor voltage, U
M,N
is unequal to the actual line volt-
age U
L
, the calculated current I
FC,L
must be corrected with the ratio between these
voltages and with the following equation:
The equation is:
,
= 1.1 ∗
,
∗
∗ cos ∗ ((
,
)/( ))
The chosen RHF filter module must have an equal nominal current I
RMS
, which
complies with the line input current of the frequency converter or which is larger.
"
≥
,
Do not oversize the RHF. The best harmonic performance is obtained at nominal filter load.
Using an oversized filter will most likely result in worse THDI performance.
If several frequency converters are operated on the same filter module, the RHF
filter module must be dimensioned with the sum of the calculated line input cur-
rents.
Stop!
If the RHF module is sized for a specified load and the motor is exchanged or modified
afterwards, the current must be calculated again to prevent an overload of the filter
module.
STOP
