Troubleshooting Of Etr - Mitsubishi Electric V Series Instruction Manual

19. Troubleshooting of ETR

If you have encountered a trouble during operation, check the following items.
1. Current is displayed as 0 A when you perform a test with the field test device.
While the test signal and voltage are input by the field test device, the LCD indicates the current value as 0 A
according to the specifications.
If you perform a trip test with the field test device while supplying power to ETR through the control power
sources (P3 or P4), the following operations will occur.
• While test signals are being input, the indicated values of load current and harmonic current will all be 0 A.
• If a test signal exceeding the pre-alarm current setting (Ip) is input by the field test device, the current
indication will be kept at 0 A and the back light will change from white to red.
• If a trip operation is performed by the field test device, the back light will change from white to red and the
fault current value will be displayed on the trip information screen.
While voltage is supplied from the test terminal of the field test device, the current indication on LCD will be
kept at 0 A.
2. The load current indication is 0 A even during energization.
If the measured current value is less than 1.5% of the rated current, the value is cut off so that the indication
is 0 A.
3. The elapsed time since fault occurrence is displyed as "----".
If control power (P3 or P4) turns off after fault occurrence when the elapsed time is short after power
application to ETR, the elapsed time since fault occurrence may be indicated as "----" because charging to
the power failure capacitor circuit in ETR is insufficient. To display the elapsed time since fault occurrence
up to 24 hours later, it is necessary to apply control power to ETR for at least 36 hours.
4. The LED display of ETR flashes.
In a dark place, the light emitted from LED may escape to the neighboring LED display.
5. The current value measured by this product is different from the value measured by the other measuring instrument.
This product indicates effective values. Check whether the measuring instrument used for comparison
measures effective values accurately. In the case of a measuring instrument which measures an average
value, the measured value may be significantly different from the effective value if there is current distortion.
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