After Repair Tests; Control Input Test - Danfoss MCD500 Service Manual

Troubleshooting
This test is performed using either an AC voltmeter.
1. Connect the MCD 500 to mains voltage, control
voltage and to a motor.
2. Measure the voltage across each phase (L1-T1, L2-
T2, L3-T3). This should be close to the nominal
mains voltage (phase voltage for in-line connection
and line voltage for inside delta connection).
•
If the voltage is zero, the SCR on that phase may
have failed.
•
If the voltage is not equivalent to the nominal
mains voltage, the bypass contactor may be
damaged and should be replaced.
3. Command the soft starter to start. After a
successful start, you should hear the bypass
contactors close.
•
If the bypass contactors do not close, the bypass
contactor, Main Control PCB, Model PCB or Bypass
Driver PCB (models MCD5-0131B - MCD5-0215B
only) may be faulty or there may be a faulty
connection between these components.
4. When the soft starter is running, measure the
voltage across each phase. This should be less than
0.5 VAC.
5. Command the soft starter to stop and listen for the
bypass contactor to open.
NOTE
The bypass contactors used in the MCD 5-0021B ~
MCD5-0105B are latching. The MCD 500 control circuits are
designed to open the bypass contactors even in the event of
removal or loss of control voltage. However it is still possible
that the bypass contactor may be closed when there is no
control supply to the soft starter. The bypass contactors will
open when control voltage is next applied.

2.1.4 After Repair Tests

NOTE
The servicing technician is responsible for ensuring that all
electrical safety tests have been completed in accordance
with local regulations.
To test that the soft starter functions correctly after
reassembly
1. Apply control power only to the soft starter.
2. Ensure that the welcome screen displays the
correct Control/Mode/HMI firmware versions.
3. Perform a Run Simulation test using both the LCP
and remote switches.
4. Connect mains supply and motor. Test that the soft
starter functions as expected.
MCD 500 Service Manual
To test the operation of the soft starter with a small motor (ie
a motor with a current rating which is much lower than that
of the soft starter)
NOTE
Ensure that 2-4 Undercurrent Trip is reset to its default value
after conducting tests.

2.1.5 Control Input Test

This procedure tests the condition of the soft starter control
inputs. This test is performed using a wire link.
®
MG.17.L4.02 - VLT is a registered Danfoss trademark
1. Use the tools menu to load the Factory Default
parameter file for the soft starter.
2. Disable 2-4 Undercurrent Trip.
3. Connect a small motor to the output terminals of
the soft starter. Test that the soft starter functions
as expected.
1. Disconnect all external wiring from the soft starter's
control inputs.
2. Control voltage must still be connected to the soft
starter.
3. Connect a wire link between each input.
•
If the corresponding LED lights up then the input is
operating correctly
•
If the LED does not light up, the control input is
damaged. Replace the Main Control PCB
2 2
5