Mitsubishi Electric FR-D720-008 Instruction Manual page 254

Causes and corrective actions
Operation panel
PS
indication
Name
PU stop
Stop with
Description
page 156 .)
Check point
Check for a stop made by pressing
Corrective action
Turn the start signal OFF and release with
Operation panel
RB
indication
Name Regenerative brake prealarm
Appears if the regenerative brake duty reaches or exceeds 85% of the Pr. 70 Special regenerative brake duty value.
When the setting of Pr. 70 Special regenerative brake duty is the initial value (Pr. 70 = "0"), this warning does not occur.
If the regenerative brake duty reaches 100%, a regenerative overvoltage (E. OV_) occurs.
Description
The RBP signal can be simultaneously output with the [RB] display. For the terminal used for the RBP signal output,
assign the function by setting "7 (positive logic) or 107 (negative logic)" in Pr. 190 or Pr. 192 (output terminal function
selection). (Refer to page 117).
1. Check that the brake resistor duty is not high.
Check point
2. Check that the Pr. 30 Regenerative function selection and Pr. 70 Special regenerative brake duty settings are correct.
1. Increase the deceleration time.
Corrective action
2. Check that the Pr. 30 Regenerative function selection and Pr. 70 Special regenerative brake duty settings.
Operation panel
TH
indication
Name Electronic thermal relay function prealarm
Appears if the cumulative value of the Pr. 9 Electronic thermal O/L relay reaches or exceeds 85% of the preset level. If
it reaches 100% of the Pr. 9 Electronic thermal O/L relay setting, a motor overload trip (E. THM) occurs.
Description The THP signal can be simultaneously output with the [TH] display. For the terminal used for THP signal output,
assign the function by setting "8 (positive logic) or 108 (negative logic)" in Pr. 190 or Pr. 192 (output terminal function
selection). (Refer to page 117).
1. Check for large load or sudden acceleration.
Check point
2. Is the Pr. 9 Electronic thermal O/L relay setting is appropriate? (Refer to page 98)
1. Reduce the load and frequency of operation.
Corrective action
2. Set an appropriate value in Pr. 9 Electronic thermal O/L relay. (Refer to page 98)
Operation panel
MT
indication
Name
Maintenance signal output
Indicates that the cumulative energization time of the inverter has reached a given time.
Description When the setting of Pr. 504 Maintenance timer alarm output set time is the initial value (Pr. 504 = "9999"), this warning
does not occur.
The Pr. 503 Maintenance timer setting is larger than the Pr. 504 Maintenance timer alarm output set time setting. (Refer to
Check point
page 231).
Corrective action Setting "0" in Pr. 503 Maintenance timer erases the signal.
Operation panel
UV
indication
Name
Undervoltage
If the power supply voltage of the inverter decreases, the control circuit will not perform normal functions. In addition,
the motor torque will be insufficient and/or heat generation will increase. To prevent this, if the power supply voltage
decreases below about 115VAC (about 230VAC for 400V class, about 58VAC for 100V class), this function stops the
Description
inverter output and displays
An alarm is reset when the voltage returns to normal.
Check point Check that the power supply voltage is normal.
Corrective action Check the power supply system equipment such as power supply.
250
FR-PU04
FR-PU07
of the PU is set in Pr. 75 Reset selection/disconnected PU detection/PU stop selection. (For Pr. 75 refer to
of the operation panel.
FR-PU04
FR-PU07
FR-PU04
FR-PU07
FR-PU04
FR-PU07
FR-PU04
FR-PU07
.
PS
.
RB
TH
——
MT
——