The Length Of Motor Cable - Delta C2000 series User Manual

The length of motor cable

When motor is driven by an AC motor drive of PWM type, the motor terminals will experience surge voltages easily
due to components conversion of AC motor drive and cable capacitance. When the motor cable is very long
(especially for the 460V series), surge voltages may reduce insulation quality. To prevent this situation, please
follow the rules below:
Use a motor with enhanced insulation.
Connect an output reactor (optional) to the output terminals of the AC motor drive
The length of the cable between AC motor drive and motor should be as short as possible (10 to 20 m or less)
For models 7.5hp and above:
Insulation level of motor
460VAC input voltage
230VAC input voltage
For models 5hp and less:
Insulation level of motor
460VAC input voltage
230VAC input voltage
NOTE
Never connect phase lead capacitors or surge absorbers to the output terminals of the AC motor drive.
If the length is too long, the stray capacitance between cables will increase and may cause leakage current. It
will activate the protection of over current, increase leakage current or not insure the correction of current
display. The worst case is that AC motor drive may damage.
If more than one motor is connected to the AC motor drive, the total wiring length is the sum of the wiring
length from AC motor drive to each motor.
For the 460V series AC motor drive, when an overload relay is installed between the drive and the motor to
protect motor over heating, the connecting cable must be shorter than 50m. However, an overload relay
malfunction may still occur. To prevent the malfunction, install an output reactor (optional) to the drive or lower
the carrier frequency setting (Pr.00-17).
NOTE
When a thermal O/L relay protected by motor is used between AC motor drive and motor, it may malfunction
(especially for 460V series), even if the length of motor cable is only 165 ft (50m) or less. To prevent it, please use
AC reactor and/or lower the carrier frequency (Pr. 00-17 PWM carrier frequency).
Chapter 7 Optional Accessories|C2000 Series
Saddle on both ends
Saddle on one end
Figure 2
1000V
66 ft (20m) 328 ft (100m)
1312 ft (400m) 1312 ft (400m)
1000V
66 ft (20m) 165 ft (50m)
328 ft (100m) 328 ft (100m)
7-13
1300V 1600V
1312 ft (400m)
1312 ft (400m)
1300V 1600V
165 ft (50m)
328 ft (100m)