Chapter 3   Ambient Environment and Installation 
3-8 
z  When the connection between the inverter and the motor is too long,consider the voltage drop 
of the cables. Phase-to-phase voltage drop (V) = 
3 ×resistance of wire (/km)×length of line (m)×current×10
-3
.  
z  Carrier frequency must be adjusted based on the motor cable length. 
Cable length between the 
inverter and the motor 
Below 75ft  Below 150ft Below 300ft  Above 300ft
Recommended 
carrier frequency 
Below 15KHz Below 12KHz Below 8KHz  Below 5KHz
Setting of parameter 10-03  15  12  8  5 
(B) The control circuit wiring must be separated and routed away from the main circuit control line or 
other high voltage or current power lines to avoid noise interference 
z  To avoid erroneous operation caused by noise interference, shield the control circuit wiring 
with twisted-wires, and connect the shielded wire to a ground terminal. Refer to the figure 
below. The wiring distance should not exceed 50 meters. 
z   
 
 
(C)Inverter Ground terminal must be connected to installation ground correctly and according to the 
required local wiring regulations. 
For 200V class ground resistance should be 100 or less.  
For 400V class ground resistance should be 10   or less. 
●Ground cable size must be according to the required local wiring regulations. The shorter the better. 
●Do not share the ground of the inverter with other high current loads   
(Welding machine, high power motor). Connect the terminals to their own ground. 
●Do not make a loop when several inverters share a common ground point. 
 
                            (a) Good      (b) Good       (c) Bad 
 
(D) To ensure maximum safety, use correct wire size for the main power circuit and control circuit. 
(According to the required local regulations) 
(E) Verify that all wiring is correct, wires are intact, and terminal screws are secured. 
Shielding sheath
Protective coverin
To ground terminal 
Wrapped with insulating tape 
Do not connect this end
Figure 3-5 Control Cable requirements 
Figure 3-6 Grounding Examples