7
Output chokes
Manual – Accessories
38
7
Output chokes
Type
LTE-B+
LTP-B
HD LT xxx xxx xx
X
X
X = available
− = not available
3186116363
Output chokes improve the quality of the output wave shape. When an output choke is
used, the maximum cable length can be doubled. For information on cable length,
refer to the technical data in the operating instructions or in the catalog of the fre-
quency inverter MOVITRAC
®
LT.
The frequency inverter has unfiltered outputs. In most applications, a satisfactory per-
formance is achieved this way. However, for some applications, an output filter is
highly recommended to improve the functionality, reliability and service life of the sys-
tem. These include:
•
Long motor cables up to 300 m (the nominal length can be doubled when using an
output choke), requires PWM frequency ≤ 4 kHz.
•
High capacity motor cable (e.g. "Pyro" wire for fire protection).
•
Several motors connected in parallel.
•
Motors without insulation suited for inverters (usually older motors).
A series of high-quality output chokes with the following main features are available for
the frequency inverter:
•
Limiting of output voltage drop, usually < 200 V/µs.
•
Limiting of transient overvoltage at the motor terminals, usually < 1000 V.
•
Suppressing line-related interference in low frequency ranges.
•
Compensating capacitive load currents.
•
Reducing HF interference emission of the motor cable.
•
Reducing motor losses and audible noise caused by ripple.
23540052/EN – 06/2018
