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Control Input Test
This is a dynamic test that verifies the correct
operation of the MCD3000 soft starter remote control
inputs. This test must be performed with the soft
starter powered up. You will need a low voltage DC
multimeter. Use the following procedure:
1. With nothing connect ed into a remote control
input, the input status LED (yellow) should be
extinguished.
2. Measure the voltage across the remote control
input. It should be between 18 and 24VDC.
3. If the measured voltage is significantly less than
18VDC this could indicate damage to the remote
control input circuit of the MCD3000 Main Control
Module. Exchange the Main Control Module to
see if the fault is removed. This damage is caused
by external voltage applied to the remote control
input. These inputs are active 24VDC and must
be controlled with volt free contacts. (Refer to
Section 5.3, Remote Control Input failure).
4. With an externally closed contact/switch
connected into a remote control input, the input
status LED (yellow) should be illuminated.
5. The measured voltage across the remote control
input should be close to zero VDC.
6. If the measured voltage is significantly higher than
18VDC this could indicate a faulty external field
contact/switch or a break in the external control
circuitry. This fault can be verified by removing the
external control circuit wired into the remote
control input and replacing this with a wire link at
the soft starter remote control input terminal. The
measured voltage across this input should be
close to zero VDC.
Power Transformer Test
This is a dynamic test that verifies the MCD3000 soft
starter control supply transformer (PT). This test must
be performed with the soft starter control supply
power on. You will need a low voltage AC multimeter.
Use the following procedure:
1. The control supply transformer has a secondary
winding consisting of two orange wires and one
purple wire. These three wires along with an earth
wire are connected to a plastic connector block
that the Main Control Module is seated into.
2. Remove the Main Control Module from the soft
starter.
3. At the plastic connector block measure the
voltage between each orange wire and the purple
wire. This should be 9 to 14VAC. If no voltage is
present the control transformer could be faulty or
no control supply is present at terminals A1/A2 or
16
MCD3000 Series
A 2/A3 of the MCD3000 soft starter. If the
measured voltage is less than 40% of the
expected voltage, check the external power
supply. The supply connected to terminals A1/A2
or A2/A3 of the soft starter could be incorrect.
4. At the plastic connector block measure the
voltage between the two orange wires. This
should be 18 to 28VAC. If no voltage is present
the control transformer could be faulty or no
control supply is present at terminals A1/A2 or
A2/A3 of the MCD3000 soft starter. If the
measured voltage is less than 40% of the
expected voltage, check the external power
supply. The supply connected to terminals A1/A2
or A2/A3 of the soft starter could be incorrect.
5. On models MCD3030 to MCD3800 the control
supply transformer has a secondary winding
consisting of two white wires. On models
MCD3030 to MCD3110, these wires are
connected to the Identity Module. On models
MCD3132 to MCD3800, these wires are
connected to a bridge rectifier.
6. Measure the voltage between the two white wires
at the Identity Module or the bridge rectifier. This
should be 18 to 28VAC. If no voltage is present
the control transformer could be faulty or no
control supply is present at terminals A1/A2 or
A2/A3 of the soft starter. If the measured voltage
is less than 40% of the expected voltage, check
the external power supply. The supply connected
to terminals A1/A2 or A2/A3 of the soft starter
could be incorrect.
ALWAYS VERIFY A SUSPECT MAIN
CONTROL MODULE BY REFITTING
IT BACK ONTO THE SOFT STARTER
UNIT TO SEE IF THE FAULT
REMAINS.
The MCD3000 contains dangerous
voltages when connected to line voltage.
Only a competent electrician should carry
out the electrical testing procedures. Improper testing
of the MCD3000 may cause equipment failure, serious
injury or death. Follow these procedures, National
®
Electrical Codes (NEC
) and local safety codes.
MG.15.B2.02 – VLT is a registered Danfoss trademark
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