Hitachi SJ Series User Manual page 603

Chapter 18
E007 Overvoltage error
Too high P-N voltage results in a failure. To prevent
this, the inverter turns OFF its output. When P-N
voltage exceeds approx. 410Vdc (200V class) or
approx. 820Vdc (400V class), the output is turned
OFF. By setting the parameter, you can perform
retries for a fixed number of times without generating
an error.
Occurrence Estimated cause(s)
• Insufficient deceleration
Error occurred
during time
• Load inertia is large.
deceleration.
• Load inertia is large.
Error occurred
during operation.
• Rotated by external
force (fan, crane).
• Abnormality of PS
Error occurred
during stop. voltage
• Mutual interference
Error occurred
caused by 2 inverters
during drooping
trying to control motors
control
strictly.
Exemplar measures to be taken
• Setting longer deceleration time in [FA-12] may improve the
situation that the motor is rapidly decelerated. If deceleration time
cannot be shortened, you need to re-examine load condition,
enable overvoltage suppression function in [bA140] and [bA146], or
use a braking resistor, braking unit, or regenerative converter.
• If load inertia is large, high regenerative power returns from the
motor; hence an overvoltage is likely to occur. You need to
re-examine load condition, enable overvoltage suppression
function in [bA140] and [bA146], or use a braking resistor, braking
unit, or regenerative converter.
• An overvoltage is likely to occur if motor rotation speed exceeds the
output frequency (rotation speed) of inverter. You need to
re-examine load condition, enable overvoltage suppression
function in [bA140] and [bA146], or use a braking resistor, braking
unit, or regenerative converter.
• Power supply voltage may be raised or fluctuated. Re-examination
of power supply environment or use of an AC reactor may improve
the situation.
• When 2 motors driving a same shaft are controlled by 2 inverters,
both the inverters attempt to generate torques, which may result in
control divergence. The situation may be improved by setting one
of the inverters to P control. See "12.11.3 Perform Drooping
Control".
18-10
Tips/FAQ/Troubleshooting
E007