Installation guide

45
VMBME102
Problem – Alarm MS (motor protection)
Cause Troubleshooting Remedy
1. Phase drop or blown fuse. Check that all phases are present on the
terminal block for incoming supply. If not,
check the fuses in the cabinet.
Also check that all wiring is secure, if screw
terminals are used they must be properly
tightened, if phoenix flat spring terminals
are used, the cables must be secure in the
correct hole with load on the cable.
If any of the phases are not present, check
backwards towards the building’s main
electrical cabinet. If there are no phases
there, contact the network supplier.
2. Defective soft-starter. Measurement check and establish that
when the control computer gives a signal
(there must be voltage between A1 & A2 on
the soft-starter), the soft-starter releases all
three phases down to the compressor.
If the soft-starter does not release the phas-
es when it receives signals from the control
computer, replace it.
3. Defective contactor. Measurement check and establish that
when the control computer gives a signal
(there must be voltage between A1 & A2
on the contactor), the contactor releases all
three phases down to the compressor.
If the contactor does not release the phases
when it receives signals from the control
computer, replace it.
4. Defective or incorrectly set motor protec-
tion.
Use a hook-on meter to establish when the
motor protection deploys, check what the
motor protection is set to. Compare with
the table.
If the motor protection is defective, replace
it.
If incorrectly set, adjust to the correct value.
5. Cable break. Check the supply to the motor protection//
soft-starter/compressor.
If a cable is damaged, replace it.
6. Defective compressor. Measurement check the three phases (each
to zero) at the compressor. Deviations from
the average of the three values must not
be more than 12% on any of the phases.
If measurement checking the winding’s
impedance the same value must be on all
three windings.
If the compressor is defective, replace it.
Problem – Alarm sensor (all)
Cause Troubleshooting Remedy
Sensor fault alternatively cable fault. • When reading the resistance of the sen-
sors, the sensor leads must first be discon-
nected from the control equipment or
terminal block.
• First take a reading from the sensor includ-
ing cable and check against the ohm table
in the “Measurement points” section.
• If the read off value does not correspond
with the table, only measure the sensor and
check the ohm table in the “Measurement
points” section.
If the sensor gives a correct value, the cable
is defective.
If the sensor does not give a correct value,
the sensor is defective.