IS620P User Manual                                                                                Chapter 3 Wiring of Servo System
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1KM: electromagnetic contactor; 1RY: relay; 1D: bypass diode
Connect the main circuit power supply according to the preceding two gures. 
DOs (ALM+/-)  are set as fault output. Power supply is automatically cut off when the servo 
drive reports an error. Meanwhile, the fault indicator goes ON. 
Observe the following precautions when wiring the main circuit: 
1.  Do not connect the input power cables to the output terminals U, V and W. Failure to 
comply will cause damage to the servo drive. 
2.  When cables are bundled together in a duct, take current reduction into consideration 
since the cooling condition becomes poor.
3.  Common cables become quickly aged in high temperature environment and easily sclerotic 
and broken in low temperature environment. Thus, use high-temperature cables in high 
temperature environment and take thermal measures in low temperature environment. 
4.  The bending radius of a cable shall exceed 10 times that of its outer diameter to prevent 
the internal wire core from breaking due to long time bending. 
5.  Select and use cables with withstand voltage of 600 VAC (and above) and temperature 
of 75°C (and above). Under the ambient temperature of 30°C and with normal cooling 
conditions, the allowable current density of the cables shall not exceed 8 A/mm
2
 when the 
total current is below 50 A, or 5 A/mm
2
 when the total current is above 50 A. This value 
shall be adjusted when the ambient temperature is high or when the cables are bundled. 
The allowable current density (A/mm
2
) can be calculated as below: 
Allowable current density = 8 x Current reduction coefcient of conductor x Current 
augmenting coefcient
Current augmenting coefficient = (Max. allowable temperature of cable - Ambient temperature)/ 30
Table 3-6 Current reduction coefcient of 
conductor
No. of Cables in 
the Same Duct
Current Reduction 
Coefcient
≤ 3 0.7
4 0.63
5 to 6 0.56
7 to 15 0.49
6.  The regen resistor cannot be connected between terminals 
 and  . Failure to comply 
may cause a re. 
7.  Do not bundle power cables and signal cables together or run them through the same 
duct. Power and signal cables shall be separated by at least 30 cm to prevent interference. 
8.  Hazardous voltage may still remain in the servo drive when the power supply is cut off. Do 
not touch the power terminals within 5 minutes after power-off.