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KFU 2-/4-
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5.4.3.3
Motor cable length, with sinus filter
Motor cables can be much longer if sinus filters are used. By conversion in sinus-
shaped currents, high-frequency portions which might limit the cable length are filtered
out. Also consider the voltage drop across the cable length and the resulting voltage
drop at the sinus filter. The voltage drop results in an increase of the output current.
Check that the frequency inverter can deliver the higher output current. This must be
considered in the projecting phase already.
If the motor cable length exceeds 300 m, please consult your supplier of drive sys-
tems..
5.4.3.4 Group
drive
In the case of a group drive (several motors at one frequency inverter), the total length
shall be divided across the individual motors according to the value given in the table.
Please note that group drive with synchronous servomotors is not possible.
Use a thermal monitoring element on each motor (e.g. PTC resistor) in order to avoid
damage.
5.4.3.5
Speed sensor connection
Install sensor cables physically separate from motor cables. Comply with the sensor
manufacturer's specifications.
Connect the shield close to the frequency inverter and limit the length to the necessary
minimum.
5.4.4
Connection of a Brake Resistor
Connection of a brake resistor is done via terminal
X2
.
Danger!
Switch off power supply
before connecting or disconnecting the brake
resistor cables to terminal
X2.
Dangerous voltage may be present at the
motor terminals and the terminals of the brake resistor even after the
frequency inverter has been disconnected safely from power supply. Wait
for some minutes until the DC link capacitors have discharged before
starting to work at the unit.
The unit may only be connected with the power supply switched off.
Make sure that the frequency inverter is discharged.
Caution!
The brake resistor must be equipped with a temperature switch. The
temperature switch must disconnect the frequency inverter from mains
supply if the brake resistor is overloaded.
L1 L2 L3
K1
K1
R
b
T1
Rb1
Rb2
T2
Rb2
Rb1
X2
X1
Note:
Limit the length of the brake resistor cables to the necessary minimum.