GE Industrial Solutions AF-600 FP High Power (460V_575V 150HP and above) - Manual (Page 87)

6.3.1 No Display Test
A frequency converter with no display can be the result of several causes. Verify first that there is no display whatsoever. A single character in the display or a dot
in the upper corner of the display indicates a communication error and is typically caused by an option card not properly installed. When this condition occurs,
the green power-on LED is illuminated.
If the LCD display is completely dark and the green power-on LED is not lit, proceed with the following tests.
First test for proper input voltage.
6.3.2 Input Voltage Test
1. Apply power to frequency converter.
2. Use the DVM to measure the input mains voltage between the frequency converter input terminals in sequence:
L1 to L2
L1 to L3
L2 to L3
For 380–480 V frequency converters, all measurements must be within the range of 342–550 VAC. Readings of less than 342 VAC indicate problems with the input
mains voltage. For 525–690 V frequency converters, all measurements must be within the range of 446–759 VAC. Readings of less than 446 VAC indicate problems
with the input mains voltage.
In addition to the actual voltage reading, the balance of the voltage between the phases is also important. The frequency converter can operate within specifications
as long as the imbalance of supply voltage is not more than 3%.
GE calculates mains imbalance per an IEC specification.
Imbalance = 0.67 X (Vmax – Vmin)/Vavg
For example, if three phase readings were taken and the results were 500 VAC, 478.5 VAC, and 478.5 VAC; then 500 VAC is Vmax, 478.5 VAC is Vmin, and 485.7
VAC is Vavg, resulting in an imbalance of 3%.
Although the frequency converter can operate at higher mains imbalances, the lifetime of components, such as DC bus capacitors, will be shortened.
AF-650 GP and AF-600 FP High Power Service Manual
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