Mitsubishi Electric 800 Series Instruction Manual page 623

9
APPENDIX
APPENDIX provides the reference information for use of this product.
Refer to APPENDIX as required.
9.1
Specification comparison between PM motor
control and induction motor control
Item
Applicable motor
Number of connectable motors
Maximum starting torque
Carrier frequency
Automatic restart after instantaneous
power failure
Startup delay
Driving by the commercial power
supply
Operation during motor coasting
Maximum motor wiring length
*1 For the motor capacity, the rated motor current should be equal to or less than the inverter rated current.
If a motor with substantially low rated current compared with the inverter rated current is used, speed and torque accuracies may deteriorate due
to torque ripples, etc. Set the rated motor current to 40% or higher of the inverter rated current.
*2 For the FR-F860-00680 or lower
*3 For the FR-F860-01080 or higher
NOTE
• Before wiring, make sure that the motor is stopped. Otherwise you may get an electric shock.
• Never connect a PM motor to the commercial power supply.
• No slippage occurs with a PM motor because of its characteristic. If a PM motor, which took over an induction motor, is
driven at the same frequency as for the general-purpose motor, the rotation speed of the PM motor becomes faster by the
amount of the general-purpose motor's slippage. Adjust the speed command to run the PM motor at the same speed as
the induction motor, as required.
622
9. APPENDIX
9.1 Specification comparison between PM motor control and induction motor control
PM motor control
PM motor (tuning required)
(The same capacity as the inverter capacity)
1: 1
50%
Four patterns of 2 kHz, 6 kHz, 10 kHz, and 14
*2
kHz
Two patterns of 2 kHz and 6 kHz
No startup waiting time.
Using the regeneration avoidance function
together is recommended.
Startup delay of about 0.1 s for initial tuning.
Not available
Never connect a PM motor to the commercial
power supply.
While the motor is coasting, an electrical
potential is generated across motor terminals.
Before wiring, make sure that the motor is
stopped.
100 m or shorter
Induction motor control
Induction motor
Several motors can be driven under V/F control.
120% (Advanced magnetic flux vector control)
Selectable between 0.75 kHz to 14.5 kHz
*3
0.75 kHz to 6 kHz
Startup waiting time exists.
No startup delay.
Can be driven by the commercial power supply.
While the motor is coasting, no potential is
generated across motor terminals.
Overall length: 500 m or shorter
*1
*2
*3