Speed Does Not Accelerate; Unable To Write Parameter Setting - Mitsubishi Electric FR-E700 Instruction Manual

Troubleshooting
7.6.12

Speed does not accelerate

Check Points
Input signal
Parameter
setting
Main circuit
7.6.13

Unable to write parameter setting

Check Points
Input signal
Parameter
setting
FR-E700 SC EC/ENE
Possible Cause
Start command and frequency command are
chattering.
The wiring length used for analog frequency
command is too long, and it is causing a volt-
age (current) drop.
Input signal lines are affected by external
EMI.
Pr. 1, Pr. 2, Pr. 18, calibration parameter C2 to
C7 settings are improper.
Torque boost (Pr. 0, Pr. 46) setting is improper
under V/F control, so the stall prevention
function is activated.
V/F pattern is improper when V/F control is
performed. (Pr. 3, Pr. 14, Pr. 19)
Stall prevention is activated due to a heavy
load.
Auto tuning is not performed under
Advanced magnetic flux vector control or
General-purpose magnetic flux vector con-
trol.
During PID control, output frequency is automatically controlled to make measured value =
set point.
Brake resistor is connected between terminal
P/+ and P1 or between terminal P1 and PR by
mistake.
Possible Cause
Operation is being performed (signal STF or
STR is ON).
You are attempting to set the parameter in
the External operation mode.
Parameter is disabled by the Pr. 77 "Parame-
ter write selection" setting.
Key lock is activated by the Pr. 161 "Fre-
quency setting/key lock operation selection"
setting.
Operation mode and a writing device do not
correspond.
Check first when you have troubles
Countermeasures
Check if the start command and the fre-
quency command are correct.
Perform analog input bias/gain calibration.
Take countermeasures against EMI, such as
using shielded wires for input signal lines.
Check the settings of Pr. 1 "Maximum fre-
quency" and Pr. 2 "Minimum frequency". If
you want to run the motor at 120Hz or
higher, set Pr. 18 "High speed maximum fre-
quency".
Check the calibration parameter C2 to C7 set-
tings.
Increase/decrease Pr. 0 "Torque boost" set-
ting value by 0.5% increments so that stall
prevention does not occur.
Set rated frequency of the motor to Pr. 3
"Base frequency". Use Pr. 19 "Base frequency
voltage" to set the base voltage (e.g. rated
motor voltage).
Change Pr. 14 "Load pattern selection"
according to the load characteristic.
Reduce the load weight.
Set Pr. 22 "Stall prevention operation level"
higher according to the load. (Setting Pr. 22
too large may result in frequent overcurrent
trip (E.OC ).)
Check the capacities of the inverter and the
motor.
Perform offline auto tuning.
Connect an optional brake transistor (MRS
type, FR-ABR) between terminal P/+ and PR.
Countermeasures
Stop the operation.
When Pr. 77 = "0" (initial value), write is ena-
bled only during a stop.
Choose the PU operation mode.
Or, set Pr. 77 = "2" to enable parameter write
regardless of the operation mode.
Check Pr. 77 "Parameter write selection" set-
ting.
Check Pr. 161 "Frequency setting/key lock
operation selection" setting.
Check Pr. 79, Pr. 338, Pr. 339, Pr. 550, Pr. 551,
and select an operation mode suitable for
the purpose.
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