Delta Compact Drive MS300 IP66/NEMA 4X Series User Manual page 66

Chapter 7 Optional Accessories  MS300 (IP66 / NEMA 4X)
Length of the Motor Cable
1. Leakage current affects the motor and remedies
Due to larger parasitic capacitances in longer motor cables, longer cables increase the leakage
current. This can activate the over-current protection and display the incorrect current. In the worst
case, it can damage the drive.
If more than one motor is connected to the AC motor drive, the total motor cable length is the sum of
the cable length from AC motor drive to each motor.
For 460V series AC motor drives, when an overload relay is installed between the drive and the motor
to protect the motor from overheating, the connecting cable must be shorter than 50 m.
However, the overload relay could still malfunction. To prevent this, install an AC output reactor
(optional) to the drive and/or lower the carrier frequency setting (Pr.00-17).
2. Surge voltage affects the motor and remedies
When a PWM signal from an AC motor drive drives the motor, the motor terminals can easily
experience surge voltages (dv/dt) due to IGBT switching and cable capacitance. When the motor
cable is very long (especially for the 460V series), surge voltages (dv/dt) may reduce motor insulation
quality. To prevent this situation, follow the rules listed below.
a. Use a motor with enhanced insulation.
b. Connect an output reactor (optional) to the output terminals of the AC motor drive.
c. Reduce the motor cable length to the values in the table below.
The suggested motor shielded cable length in the following table complies with IEC 60034-17,
which is suitable for motors with a rated voltage ≤ 500 V
460V Three-phase
Model
VFD1A5MS43MNSAA
VFD1A5MS43MFSAA
VFD2A7MS43MNSAA
VFD2A7MS43MFSAA
VFD4A2MS43MNSAA
VFD4A2MS43MFSAA
VFD5A5MS43MNSAA
VFD5A5MS43MFSAA
VFD9A0MS43MNSAA
VFD9A0MS43MFSAA
VFD13AMS43MNSAA
VFD13AMS43MFSAA
VFD17AMS43MNSAA
VFD17AMS43MFSAA
Without AC Reactor
Shielded Cable Non-shielded
[meter] Cable [meter]
35
35
35
50
50
50
100
7-16
and with an insulation level of ≥ 1.35 kV
AC
With AC Reactor
Shielded Cable
[meter]
50 50
50 50
50 50
75 75
75 75
75 75
150 150
p-p
Non-shielded
Cable [meter]
90
90
90
115
115
115
225