Danfoss MCD500 Service Manual

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Danfoss MCD500 Service Manual Manual pdf 6 page image

This test is performed using either an AC voltmeter.1. Connect the MCD 500 to mains voltage, controlvoltage and to a motor.2. Measure the voltage across each phase (L1-T1, L2-T2, L3-T3). This should be close to the nominalmains voltage (phase voltage for in-line connectionand line voltage for inside delta connection).• If the voltage is zero, the SCR on that phase mayhave failed.• If the voltage is not equivalent to the nominalmains voltage, the bypass contactor may bedamaged and should be replaced.3. Command the soft starter to start. After asuccessful start, you should hear the bypasscontactors close.• If the bypass contactors do not close, the bypasscontactor, Main Control PCB, Model PCB or BypassDriver PCB (models MCD5-0131B - MCD5-0215Bonly) may be faulty or there may be a faultyconnection between these components.4. When the soft starter is running, measure thevoltage across each phase. This should be less than0.5 VAC.5. Command the soft starter to stop and listen for thebypass contactor to open.NOTEThe bypass contactors used in the MCD 5-0021B ~MCD5-0105B are latching. The MCD 500 control circuits aredesigned to open the bypass contactors even in the event ofremoval or loss of control voltage. However it is still possiblethat the bypass contactor may be closed when there is nocontrol supply to the soft starter. The bypass contactors willopen when control voltage is next applied.2.1.4 After Repair TestsNOTEThe servicing technician is responsible for ensuring that allelectrical safety tests have been completed in accordancewith local regulations.To test that the soft starter functions correctly afterreassembly1. Apply control power only to the soft starter.2. Ensure that the welcome screen displays thecorrect Control/Mode/HMI firmware versions.3. Perform a Run Simulation test using both the LCPand remote switches.4. Connect mains supply and motor. Test that the softstarter functions as expected.To test the operation of the soft starter with a small motor (iea motor with a current rating which is much lower than thatof the soft starter)1. Use the tools menu to load the Factory Defaultparameter file for the soft starter.2. Disable 2-4 Undercurrent Trip.3. Connect a small motor to the output terminals ofthe soft starter. Test that the soft starter functionsas expected.NOTEEnsure that 2-4 Undercurrent Trip is reset to its default valueafter conducting tests.2.1.5 Control Input TestThis procedure tests the condition of the soft starter controlinputs. This test is performed using a wire link.1. Disconnect all external wiring from the soft starter'scontrol inputs.2. Control voltage must still be connected to the softstarter.3. Connect a wire link between each input.• If the corresponding LED lights up then the input isoperating correctly• If the LED does not light up, the control input isdamaged. Replace the Main Control PCBTroubleshooting MCD 500 Service ManualMG.17.L4.02 - VLT® is a registered Danfoss trademark 52 2