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4.5 Fault Symptoms
4.5.1 No Display
The LCP display provides two display indica-
tions. One by means of the backlit LCD alpha-
numeric display. The other is three LED
indicators lights near the bottom of the LCP.
If the green power-on LED is illuminated but
the backlit display is dark, this indicates that
the LCP itself is defective and must be re-
placed.
Be certain, however, that the display is completely dark. Having a single character in the upper
corner of the LCP or just a dot indicates that communications may have failed with the control
card. This is typically seen when a serial bus communication option has been installed in the
frequency converter and is either not connected properly or is malfunctioning.
If neither indication is available, then the source of the problem may be elsewhere. Proceed to
the No Display test (6.3.1) to carry out further troubleshooting steps.
4.5.2 Intermittent Display
Cutting out or flashing of the entire display and power LED indicates that the power supply (SMPS)
is shutting down as a result of being overloaded. This may be due to improper control wiring or
a fault within the adjustable frequency drive itself.
The first step is to rule out a problem in the control wiring. To do this, disconnect all control wiring
by unplugging the control terminal blocks from the control card.
If the display stays lit, then the problem is in the control wiring (external to the adjustable fre-
quency drive). All control wiring should be checked for shorts or incorrect connections.
If the display continues to cut out, follow the procedure for No Display as though the display were
not lit at all.
4 Troubleshooting
High Power Service Manual for VLT
®
FC Series
Adjustable Frequency Drives
4-4
MG.90.L1.22 - VLT
®
is a registered Danfoss trademark
4
Содержание VLT HVAC FC 100
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