4.4 Visual Inspection
Visually inspect the conditions in Table 4.1 as part of any initial troubleshooting procedure.
Inspect for Description
Auxiliary equipment
•
Look if more auxiliary equipment, switches, disconnects, or input fuses/circuit breakers reside on the
input power side of frequency converter or output side to motor.
•
Examine operation and condition of these items as possible causes for operational faults.
•
Check function and installation of pressure sensors or encoders, and other equipment used for
feedback to the frequency converter.
Cable routing
•
Avoid routing motor wiring, AC line wiring, and signal wiring in parallel. If parallel routing is
unavoidable, maintain a separation of 150–200 mm (6–8 inches) between the cables or separate them
with a grounded conductive partition.
•
Avoid routing cables through free air.
Control wiring
•
Check for broken or damaged wires and connections.
•
Check the voltage source of the signals. Though not always necessary depending on the installation
conditions, the use of screened cable or a twisted pair is recommended.
•
Ensure that the screen is terminated correctly.
Frequency converter cooling Check operational status of all cooling fans:
•
When voltage is applied to the frequency converter, the fan activates for a few seconds.
•
Check for blockage or constrained air passages.
Frequency converter display The display shows important items, such as:
•
Warnings.
•
Alarms.
•
Frequency converter status.
•
Fault history.
Frequency converter interior
•
Check that the frequency converter interior is free of:
- Dirt.
- Metal chips.
- Moisture.
- Corrosion.
•
Check for burnt or damaged power components, or carbon deposits that are the result of a
catastrophic component failure.
•
Check for cracks or breaks in the housings of power semiconductors, or pieces of broken component
housings, which are loose inside the unit.
EMC considerations
•
Check for proper installation regarding electromagnetic capability.
•
Refer to the frequency converter operating instructions and this chapter for further details.
Environmental conditions
•
Under
specic
conditions, these units can be operated within a maximum ambient of 50
°
C (122
°
F).
•
Humidity levels must be less than 95% non-condensing.
•
Check for harmful airborne contaminates such as sulfur-based compounds.
GLCP
•
If supplied, check that the GLCP is correctly installed, and that the display is lit when powered on.
Grounding
•
The frequency converter requires a dedicated ground wire from its enclosure to the building ground.
It is also suggested to ground the motor to the frequency converter enclosure.
•
The use of conduit or mounting of the frequency converter to a metal surface is not considered to
be suitable grounding.
•
Check for good ground connections that are tight and free of oxidation.
Troubleshooting
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