To Further Prevent A Trip (Pr.154); Trip During Stall Prevention Operation (Pr.874) - Mitsubishi Electric FR-F800 Instruction Manual

(H) Protective function parameter
To further prevent a trip (Pr.154)
• When Pr.154 Voltage reduction selection during stall prevention operation = "0, 10", the output voltage is reduced. By
making this setting, an overcurrent trip becomes less likely to occur. Use this setting when torque reduction does not pose
a problem. (Under V/F control, the output voltage is reduced only during the stall prevention operation is activated.)
• Set Pr.154 = "10, 11" when the overvoltage protective function (E.OV[ ]) activates during stall prevention operation in an
application with large load inertia. Note that turning OFF the start signal (STF/STR) or varying the frequency command
during stall prevention operation may delay the acceleration/deceleration start.
Pr.154 E.OC[ ] countermeasure
0 Effective
1 (initial value) ―
10 Effective
11 ―
Trip during stall prevention operation (Pr.874)
• The inverter can be set to trip at activation of stall prevention and stalling of the motor.
• When a high load is applied and the stall prevention is activated, the motor stalls. At this time, if the rotation speed is lower
than 1.5 Hz and the output torque exceeds the level set in Pr.874 OLT level setting and such a state continues for 3 s, stall
prevention stop (E.OLT) is activated and the inverter output is shut off.
NOTE
• Under V/F control or Advanced magnetic flux vector control, if the output frequency drops to 0.5 Hz due to the stall prevention
operation and this state continues for 3 s, a fault indication (E.OLT) appears, and the inverter output is shut off. This operation
is activated regardless of the Pr.874 setting.
Caution
 Do not set the stall prevention operation current too low.
Doing so will reduce the generated torque.
 Be sure to perform a test run.
Stall prevention operation during acceleration may extend the acceleration time.
Stall prevention operation during constant-speed operation may cause sudden speed changes.
Stall prevention operation during deceleration may extend the deceleration time.
Parameters referred to ???????
Pr.73 Analog input selection
Pr.178 to Pr.189 (Input terminal function selection)
Pr.190 to Pr.196 (output terminal function selection)
Pr.858 Terminal 4 function assignment, Pr.868 Terminal 1 function assignment
254
PARAMETERS
E.OV[ ] countermeasure
―
―
Effective
Effective
Torque
Output torque
Output
frequency
1.5Hz
Start signal
(STF)
Fault signal
(ALM)
page 306
page 329
page 288
V/F V/F V/F Magnetic flux Magnetic flux Magnetic flux
Stall prevention limit
Pr.874
3s
E.OLT occurs
page 310
Time
Time