Delta HES Series User Manual page 156

Appendix B Optional Accessories|HES Series
U-shape metal bracket
The length of motor cable
When motor is driven by a drive of PWM type, the motor terminals will experience surge voltages easily
due to components conversion of 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 drive. The length of the cable between drive and motor should be as short as possible (10 to 20 m or
less).
For models 7.5hp/5.5kW and above:
Insulation level of motor
460Vac input voltage
230Vac input voltage
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 drive may damage.
To drive the 460V series motor, if there is one relay installed between the Hybrid Servo Controller and
motor to protect the motor from over-heating, the relay might malfunction even if the length of the wire is
below 50 meters. Thus, a filter for output current shall be added (optional for purchase).
NOTE:
When a thermal O/L relay protected by motor is used between Hybrid Servo Controller 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 a filter.
Never connect phase lead capacitors or surge absorbers to the output terminals of the Hybrid Servo
Controller.
Protective coating required at contacts between brackets
and metal plates to ensure good contact.
Figure 1
Figure 2
1000V
66 ft (20m)
1312 ft (400m)
Metal plate with good
grounding
1300V
328 ft (100m)
1312 ft (400m)
B-14
1600V
1312 ft (400m)
1312 ft (400m)