4-201
07-13 Low voltage detection level
Range
200V: 150~210Vdc
400V: 300~420Vdc
575V: 500~600Vdc
690V: 500~600Vdc
07-25
Low voltage detection time
Range
0.00~1.00 Sec
Adjust the 07-13 voltage level from 150 to 300 Vdc (200V class) or from250 to 600 Vdc (400V class).
When the AC input voltage is lower than the 07-13 value (07-13/ 1.414 = AC voltage detection level) for the time
specified in 07-25 the low-voltage error "UV" will displayed. If 07-25 = 0.00 sec., the UV error will be displayed
immediately.
Set preventive measures:
- The inverter input voltage will limit the output voltage. If the input voltage drops excessively, or if the load is
too big, the motor may stall.
- If the input voltage drops below the value set in 07-13 then the output is turned off momentarily. The inverter
will not automatically start when power is restored.
07-14 Pre-excitation time
Range
0.00~10.00 Sec
07-15 Pre-excitation level
Range
100~200 %
If a high starting torque is required for the application, especially for a large horsepower motors, the pre-excitation
operation can be used to pre-flux (magnetize) the motor.
Pre-excitation time (07-14)
When an operation command (forward or reverse) is activated, the inverter will automatically start pre-excitation
based on the time set in parameter 07-14.
The time for the flux to reach 100% is a function value of motor’s electrical time constant (See figure 4.4.62).
Electrical time constant (quadratic by-pass circuit time constant) can be calculated by motor parameter setting
(group 02)
Electrical time constant T2=
Set the pre-excitation time (07-14) based on the electrical time constant T2
Pre-excitation initial level (07-15)
Use the pre-excitation initial level (07-15) to provide a higher excitation current during the pre-excitation time
(07-14), which will increase the speed and stability for motors.
Motor leakage inductance (02-17) + motor mutual inductance (02-18)
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