Mitsubishi Electric FR-F820-00077 Instruction Manual page 904

Specification comparison between PM motor control and induction motor control
Item
Output signal
Carrier frequency
Automatic restart after
instantaneous power failure
Startup delay
Driving by the commercial power
supply
Operation during motor coasting
Maximum motor wiring length
Tab. A-2:
For the motor capacity, the rated motor current should be equal to or less than the inverter rated
current. (It must be 0.4 kW or higher.)
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 about 40% or higher of the inverter rated current.
For the MM-EFS (1500 r/min specification), the number of motor poles differs between the 15 kW
or lower motor (6 poles) and the 18.5 kW or higher motor (8 poles). For this reason, the frequency
setting resolution also differs between them.
For the FR-F820-02330(55K) or lower and the FR-F840-01160(55K) or lower
For the FR-F820-03160(75K) or higher and the FR-F840-01800(75K) or higher
NOTES Before wiring, make sure that the motor is stopped. Otherwise you may get an electric shock.
Never connect an IPM motor to the commercial power supply.
No slippage occurs with an IPM motor because of its characteristic. If an IPM motor, which took
over an induction motor, is driven at the same frequency as for the general-purpose motor, the
running speed of the IPM motor becomes faster by the amount of the general-purpose motor's
slippage. Adjust the speed command to run the IPM motor at the same speed as the induction
motor, as required.
A - 4
PM motor control
In the initial setting, 1 mA is output at
the rated motor frequency from across
terminals FM and SD. (SD is a common
terminal.)
Pulse output for
meter The permissible frequency load current
is 2 mA.
Pulse specification: 1440 pulses/s at the
rated motor frequency.
Four patterns of 2 kHz, 6 kHz, 10 kHz, and
14 kHz
Two patterns of 2 kHz and 6 kHz
No startup waiting time.
Using the regeneration avoidance
function or retry function together is
recommended.
Startup delay of about 0.1 s for initial
tuning.
Not available
Never connect an IPM motor to the
commercial power supply.
While the motor is coasting, potential is
generated across motor terminals.
Before wiring, make sure that the motor
is stopped.
100 m or shorter
Differences between PM motor control and induction motor control (2)
Appendix
Induction motor control
In the initial setting, 1 mA is output at
60 Hz from across terminals FM and SD.
(SD is a common terminal.)
The permissible frequency load current
is 2 mA.
Pulse specification: 1440 pulses/s at
60 Hz
Selectable between 0.75 kHz to
14.5 kHz
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, potential is
not generated across motor terminals.
Overall length: 500 m or shorter