Operation's Precautions - Mitsubishi Electric FR-K-400-U Instruction Manual

(4) When the FWD start switch (or REV start switch) is turned off while the motor is rotating, motor
speed is decelerated in the time'period set by the DECEL dial. When the frequency falls below
3Hz. the DC dynamic brake will be activated and the motor will stop immediately. If the motor
speed does not decelerate smoothly and the ALARM lamp blinks during the deceleration or the
"ALARM" indication lamp lights up, this is because the deceleration time is not sufficient for the
motor load, and the deceleration time should thus be lengthened.
(5) I f the FWD start switch and the REV start switch are turned on simultaneously, the motor will not
rotate. Also, if the FWD start switch and the REV start switch are simultaneously activated while
the motor is rotating, the motor will begin decelerating in the same manner as when the FWD (or
REV) start switch is turned off.
(6) If the FWD start switch is turned off and the REV start switch turned on while the motor is rotat-
ing forward, the motor speed will decelerate t o a frequency of 3Hz. at which point the rotation
direction will automatically be reversed, accelerating gradually tothe frequency that has been set.
The same is also true of movement from reverse to forward rotation.
(7)
I f the settings of the acceleration or deceleration times are changed during motor operations, the
previous settings will remain in memory and the changes will not take effect. Note that this
unit is designed for changes in the setting of acceleration and deceleration time to be made at a
inverter frequency below 3Hz.
(8) I f the protective circuits, such a s those against overcurrent and regenerative overvoltage are
activated, the alarm indication lamp will light up in red and the shut-off state will continue. To
reset
after a shut-off, perform the following operations:
0
First turn off the power supply with the MCCB or the Magnetic contactor (MS), then turn
it
on.
0
Short-circuit the terminals between RES (reset) and SD (common) of the control circuit by the
reset switch, then (after about 0.1 second), re-open.
(9) Use the calibration resistor to adjust the frequency meter so that the frequency i s indicated a s 60,
120 or 240Hz when the commanded voltage (across terminals between 2 and 5) is set to 5V DC
or 10V DC by the frequency setting input signal select switch.
Inverters equipped with a frequency meter have already been adjusted at the factory before
shipping.
(10) When the DC dynamic brake activates at below 3Hz during deceleration,
it
may cause a high-
pitched noise. This noise is common, and does not indicate any abnormalities (The DC dynamic
brake functions for about 0.5 second.)
5.4 Operation's Precautions
When the confirmations described above have been completed you may begin normal operations, but
keep the following points in mind when doing so.
(1) When a general type motor is being driven by the inverter, the temperature, noise and vibrations
will be somewhat higher than they would be with a commercial power supply.
(2) Since cooling efficiency decreases at low speed operations,
it
is necessary to reduce the torque
from the rated motor torque. (Refer to the catalog for the torque reduction ratio.)
(3) The FREQROL-K is capable of controlling plural motors at the same time. When the inverter is
used to control more than one motor, care should be taken that the total current requirement for
the simultaneously operated motors is within the rated output current of the inverter.
(4) I f the FREQROL-K is being used to control multipole motors with 8 or more poles, submersible
motors. or other special-purpose motors, carefully examine the rated current and other electrical
specification.