Selection Of The Motor Cable; Connection Of The Motor; 2.8.3.1 Motor Cable Length For Parallel Operation Of Motors; Figure 11: Connection Of The Motor - KEB COMBIVERT F5 Instruction Manual

2.8.2

Selection of the motor cable

The correct selection and wiring of the motor cable is very important:
• lower abrasion of the motor bearings by leakage currents
• improved EMC characteristics
• lower symmetrical operating capacities
• less losses by transient currents
2.8.3

Connection of the motor

As standard the connection of the motor must be carried out in accordance with the following table:
Connection of the motor
230 V
Delta
Motor connection in star connection
PE
Figure 11:
Attention
Caution
Inverters switch with dv/dt of approx. 5kV/µs at the output. Voltage peaks at the motor which
endanger the insulation system can occur especially in case of long motor lines (> 15 m). A
motor choke, a dv/dt-filter or sine-wave filter can be used for protection of the motor.

2.8.3.1 Motor cable length for parallel operation of motors

The resulting motor cable length for parallel operation of motors, or parallel installation with
multiple cables arises from the following formula:
resulting motor cable length = ∑single line length x √number of motor lines
230/400 V motor
400 V
Star
U1 V1 W1
W2 U2 V2
Connection of the motor
The connecting-up instructions of the motor manufacturer are gener-
ally valid !
Protect motor against voltage peaks !
400/690 V motor
400 V
Delta
Motor connection in delta connection
PE
U1 V1
W2 U2
690 V
Star
W1
V2
23