7-4
-2 Measuring the capacitance of the DC link bus capacitor (during power-off time under ordinary operating
condition)
In general, the discharging condition of the DC link bus capacitor during a power-off time under the ordinary
operating condition at the end user’s installation is different from that under which the initial measurement is
conducted at the time of factory shipment. As a result, the measured data for the DC link bus capacitor may not be
updated. A method is provided, therefore, that allows you to measure the capacitance of the DC link bus capacitor
during an ordinary power-off time by taking on (assuming) its discharging condition during a power-off time under
the ordinary operation condition at the end user's installation.
Presented below is the procedure for taking on the discharging condition during a power-off time under the
ordinary operating condition at the end user’s installation.
--------------------------------------- Procedure for setting up measurement condition ---------------------------------------
1) Set function code H98 (Maintenance function) to enable the user to specify the judgment criteria for the
service life of the DC link bus capacitor (Bit 3) (refer to function code H98).
2) Place the inverter in stopped state.
3) Place the inverter in the state of power-off under ordinary operating conditions.
4) Set both function codes H42 (Capacitance of DC Link Bus Capacitor) and H47 (Initial Capacitance of DC Link
Bus Capacitor) to "0000."
5) Switch OFF the inverter.
Measure the discharging time of the DC link bus capacitor and save the result in function code H47 (Initial
Capacitance of DC Link Bus Capacitor).
The condition under which the measurement has been conducted will be automatically collected and saved.
During the measurement, " . . . . " will appear on the LED monitor.
6) Switch ON the inverter again. Confirm that H42 (Capacitance of DC Link Bus Capacitor) and H47 (Initial
Capacitance of DC Link Bus Capacitor) hold right values. Move to Menu 5 "Maintenance Information" and
confirm that the relative capacitance (ratio to full capacitance) is 100%.
If the measurement has failed, "0001" is entered into both H42 and H47. Check whether there has
been any mistake in operation and conduct the measurement again.
----------------------------------------------------------------------------------------------------------------------------------------------------
To change the settings back to the state at the time of factory shipment, set H47 (Initial Capacitance of DC Link
Bus Capacitor) to "0002"; the original values will be restored.
Hereafter, each time the inverter is switched OFF, the discharging time of the DC link bus capacitor is
automatically measured if the above condition is met.
The condition given above produces a rather large measurement error. If this mode gives you a lifetime
alarm, set H98 (Protection/Maintenance Function) back to the factory defaults (Bit 3 (Select life
udgment criteria of DC link bus capacitor) = 0) and conduct the measurement under the condition at the
time of factory shipment.
Electrolytic capacitor on the printed circuit board
Move to Menu 5 "Maintenance Information" in Programming mode and check the accumulated run time of the
electrolytic capacitor on the printed circuit board. This value is calculated from the cumulative total number of
hours a voltage has been applied on the electrolytic capacitor, adjusted with ambient temperature, and is used as
the basis for judging whether it has reached its service life. The value is displayed on the LED monitor in units of 1
hour.
Cooling fan
Select Menu 5 "Maintenance Information" and check the accumulated run time of the cooling fan. The inverter
accumulates hours for which the cooling fan has run. The display is in units of 1 hour. The accumulated time
should be used just a guide since the actual service life will be significantly affected by the temperature and
operation environment.
To Next Page
Loading...
Need help?
General
