Yaskawa P7 Drive User Manual - Manual (Page 39)

Electrical Installation 2 - 11
Cable Length between Drive and Motor
The P7 should be installed as close as possible to the motor to minimize the length of load side power cable. If the cable
between the Drive and the motor is long, the high-frequency leakage current will increase, causing the Drive output current to
increase as well. This may affect peripheral devices. To prevent this, reduce the cable length whenever possible, or if
necessary, adjust the carrier frequency (set in C6-02) as shown in Table 2.6.
Ground Wiring
Observe the following precautions when connecting the ground wire:
1.
208-240Vac Drives should have a ground connection with resistance of less than 100
Ω.
2. 480Vac Drives should have a ground connection with resistance of less than 10
Ω.
3. Do not share the ground wire with other devices, such as motors or large-current electrical equipment.
4. Always use a ground wire that complies with technical standards on electrical equipment and minimize the length of the
ground wire. Leakage current flows through the Drive. Therefore, if the distance between the ground rod and the ground
terminal is too long, potential on the ground terminal of the Drive will become unstable.
5. When using more than one Drive, be careful not to loop the ground wire. See Fig 2.2.
Fig 2.2 Ground Wiring Examples
Control Circuit Ground Terminals
The removable Drive control terminal card provides two ground terminals (marked TB3 and TB4) to accept the control wire
shield connection. The control wire shield should be connected on this end only, the opposite end should be isolated with
electrical tape.
Table 2.6 Motor Cable Length vs. Carrier Frequency (C6-02)
Motor Cable Length 164 ft. (50m) maximum 328 ft. (100m) maximum More than 328 ft.(100m)
Carrier Frequency 15kHz maximum 10kHz maximum 5kHz maximum
IMPORTANT Grounding of the P7 enclosure and motor is required for proper system operation.
NO
OK NOT OK