Visual Inspection - Danfoss VLT FC Series Service Manual

Troubleshooting

6.4 Visual Inspection

Table 6.1 lists conditions that require visual inspection as part of any initial troubleshooting procedure.
Inspect for
Auxiliary equipment
Cable routing
Control wiring
Cooling
DC fuse microswitch
DC fuse mounting
Display
Interior
EMC considerations
Environmental conditions
Grounding
Input power wiring
Motor
Output to motor wiring
Programming
Proper clearance
Vibration
Table 6.1 Visual Inspection
MG94A502
Service Guide
Check auxiliary equipment, switches, disconnects, or input fuses/circuit breakers on the input side of the
drive or the output side to the motor. Check the function and installation of pressure sensors, encoders,
or other devices that provide feedback to the drive.
Avoid routing the following in parallel:
•
Motor wiring
•
Mains wiring
•
Signal wiring
If parallel routing is unavoidable, maintain a separation of 150–200 mm (6–8 in) between cables, or
separate them with a grounded conductive partition. Avoid routing cables through free air.
Check for broken or damaged wires and connections. In parallel drive systems, check connections
between the control shelf and the modules. Check the voltage source of the signals. Use of shielded
cable or a twisted pair is recommended. Ensure that the shield is terminated correctly. See
chapter 4.9 Shielded Cable Grounding.
Check the operation of all cooling fans. Check the door filters on IP21 (UL type 1)/IP54 (UL type 12)
units. Check for blocked air passages. Verify that the bottom gland plate is installed. Check the positive
and negative interconnections between modules.
In parallel drive systems, check that microswitches have been snapped properly on to DC fuse fixtures.
In parallel drive systems, check both ends of DC fuses for loose connections.
Check the LCP display for warning/alarm messages, system status, and fault history.
Check that the drive interior is free of dirt, metal chips, moisture, and corrosion. Check for burnt or
damaged power components, or carbon deposits resulting from component failure. Check for cracks in
the housings of power semiconductors, or for pieces of broken component housings inside the unit.
Check for proper installation regarding electromagnetic compatibility (EMC). Refer to the drive operating
instructions and chapter 7.3 Electromagnetic Compatibility.
The drive can operate within a maximum ambient temperature of 50 °C (122 °F). Humidity levels must
be less than 95% non-condensing. Check for harmful airborne contaminates such as sulphur-based
compounds.
The drive requires a dedicated ground wire from its enclosure to the building ground. Grounding the
motor to the drive enclosure is recommended. The use of a conduit or mounting the drive onto a metal
surface is not considered a suitable ground. Check that ground connections are tight and free of
oxidation.
Check for loose connections, proper fusing, and blown fuses. In parallel drive systems, check cable length
and cross-section imbalance between the terminals of the modules.
Check the nameplate ratings of the motor. Ensure that the motor ratings correspond with the drive
ratings. Check that the motor parameters (parameter 1-20 Motor Power [kW] to parameter 1-25 Motor
Nominal Speed) are set according to the motor ratings.
Check for loose connections. Check for switching components in the output circuit. Check for faulty
contacts in the switchgear. In parallel drive systems, check for proper interconnections between the
modules. Check cable length and cross-section imbalance between the terminals of the modules. One
missing wire can cause an overcurrent trip.
Make sure that the drive parameter settings are correct according to motor, application, and I/O configu-
ration.
Drives require adequate top and bottom clearance to ensure proper airflow for cooling. Drives with
exposed heat sinks (in the back) must be mounted on a flat solid surface.
Look for unusual amounts of vibration around the drive. Mount the unit solidly or use shock mounts.
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