Danfoss Compressor Drives Troubleshooting Check List

Compressor Drives

Troubleshooting Check List

CDS 302/CDS 303

http://cc.danfoss.com

Check List	Content

Introduction..........................................................................................................................................	4
For Your Safety......................................................................................................................................	5
Diagnostics...........................................................................................................................................	6
Initial Trouble Shooting (visual inspection of the installation)........................................................	7
Input power wiring....................................................................................................................................................................................	7
Output to motor.........................................................................................................................................................................................	7
Grounding....................................................................................................................................................................................................	7
Control wiring.............................................................................................................................................................................................	7
Programming..............................................................................................................................................................................................	7
Compressor Motor.....................................................................................................................................................................................	7
Cable routing...............................................................................................................................................................................................	7
Peripheral equipment (sensors, contactors, etc)............................................................................................................................	7
Trip on over Temperature........................................................................................................................................................................	7
Drive interior................................................................................................................................................................................................	7
EMC Precautions.........................................................................................................................................................................................	7
Vibration........................................................................................................................................................................................................	7
Environmental conditions......................................................................................................................................................................	7
Proper clearance.........................................................................................................................................................................................	7
Trouble shooting .................................................................................................................................	8
Fault Symptoms - Display of the drive ...............................................................................................................................................	8
No display (blank display).......................................................................................................................................................................	8
Intermittent display...................................................................................................................................................................................	8
Fault Symptoms in the compressor (motor)....................................................................................................................................	9
Common drives and motor problems...............................................................................................	11
Control logic problems..........................................................................................................................................................................	11
Programming problems........................................................................................................................................................................	11
IGBT, Motor or load problems .............................................................................................................................................................	12
Procedure to conduct the dynamic test to check the IGBT .....................................................................................................	12
Faults in the drive.....................................................................................................................................................................................	12
EMC - Electro Magnetic Compatibility..............................................................................................................................................	13
Static test procedures........................................................................................................................	14
Rectifier test (static).................................................................................................................................................................................	14
IGBT static test...........................................................................................................................................................................................	15

FRCC.PC.036.A2.02 3

Check List	Introduction

Many frequency converters that are sent back to Danfoss every year for factory analysis

are diagnosed with No Fault Found (NFF). Establishing whether a frequency converter is faulty or not prior returning it to the factory can increase the uptime of the compressor solution, reduce the unnecessary use of resources and limit the number of NFF.

The purpose of this check list is to facilitate users, field technicians, engineers and service

personnel working with Danfoss frequency converters to identify faults and perform a first diagnosis on the drive before sending it to inspection and analysis.

PERFORM THE FOLLOWING FAULT DIAGNOSIS BEFORE RETURNING A FREQUENCY CONVERTER FOR FACTORY INSPECTION.

CHECK ALL POSSIBILITIES.

IN CASE OF DOUBT, PLEASE SEEK DANFOSS SUPPORT.

4 FRCC.PC.036.A2.02

Check List	For Your Safety

Figure 1: Drive must be turned OFF for 20min before repair can start

Frequency Converters (FC) contain dangerous voltages when connected to the line voltage. Only a competent technician should carry out the service.

Some instructions should be compulsorily followed to ensure safety while working with the FC.

•Do not touch electrical parts of the FC when the AC line is connected.

•Frequency converters contain DC-link capacitors that can remain charged even when the frequency converter is not powered. To avoid electrical hazards, disconnect AC mains, any permanent magnet type motors, and any

remote DC-link power supplies, including battery backups, UPS and DC-link connections to other frequency converters.

•Wait for at least 20 minutes before touching any of the components.

•When repair or inspection is done, the AC line must be disconnected.

•The STOP key on the control panel does not disconnect the AC line.

•During operation and programming of the parameters, the motor may start without warning. So you have to activate the STOP key when changing data.

FRCC.PC.036.A2.02 5

Check List	Diagnostics

WARNINGS and ALARM Fault detection via LCP: messages are displayed when the frequency converter fault circuit detects a faulty condition or an unresolved fault.

A warning light flashing display indicates potential problems.

a)In case of reset alarm: you can stop and then start the unit.

b)In case of trip-lock alarm, you have to disconnect the mains, wait for dark display, then stop and start.

There are two levels of alarms; Reset Alarms and Trip-lock Alarms.

Alarm Log	Check the content of the alarm log.
	5 latest alarms are available through the “Alarm
	Log” button key on the LCP.
	Check the alarm code and refer to the
	troubleshooting session of the Operating
	Instructions VLT® CDS 302 and CDS 303 on page
	135. It contains guidance for the complete list
	of alarms and warnings.

Figure 2: WARNINGS and ALARM messages are displayed when the

frequency converter fault detects a faulty condition

If the troubleshooting suggested does not resolve the problem, please contact Danfoss for support.

Do not exchange the drive before contacting Danfoss support.

6 FRCC.PC.036.A2.02