Trouble Shooting
22
6.2 Capacitors
6.2.1 Run capacitor
A run capacitor is installed to offset the magnetic field in the
stator windings of a electric motor. When the run capacitor
fails, the rotor will block on LRA (locked rotor amperage)
and refuses to start running. Start attempts will result in cut-
out by overload protection, repeated failed start-ups and ig-
nored overload cut-outs will eventually lead to motor fail-
ures instead of a simple capacitor replacement.
6.2.2 Start capacitor
A start capacitor is installed to offset the wave signal fre-
quency during start-up. Capacitor failures will lock the rotor
on LRA (locked rotor amperage) and refuses to start running
a electric motor. Start attempts will result in cut-out by over-
load protection, repeated failed starts and ingnored verload
cut-outs will eventually lead to complete motor failures in-
stead of a simple capacitor replacement. Start capacitor fail-
ures will most likely cause excessive voltage drops on start-
up and/or when running.
6.2.3 Trouble shooting capacitors
Broken capacitors will cause a rotor blockage on LRA,
allowing a rotor only to turn slowly or cause excessive
voltage drops.
1) When there is a presumption of a broken run capacitor
first disable one of the wires of the start capacitor when
applied.
2) Try to start the motor/compressor again, if there is still a
LRA blockage replace the run capacitor.
3) If the motor/compressor attempts to start after a
capacitor replacement and runs apparently normal,
check the running amps to see if there are no damages
to the motor windings. When the amp read-out is fare
above normal, the windings are damaged and the
motor or compressor should be replaced.
4) Re-connect the start capacitor and test again to see if
start-up and running is normal.
Faulty start capacitors will give excessive voltage drops
on start-up and/or when running. Replace start
capacitor if necessary.
6.2.4 Trouble shooting controller cards
The AC-output of a controller card is done through elec-
tronic relays also called TRIACS mounted against an heat-
sink for cooling.
All TRIACS are protected by slow fuses except the main
compressor outlets COMP1 and COMP2. TRIAC failures can
cause electrical problems.
a) a TRIAC remains open, no active current on the AC out-
let connector.
b) a TRIAC remains closed, continuously AC output
present on the connector.
When there is a presumption of a TRIAC failure first check
the protective fuses to be OK. TRIAC failures are more likely
as a OPTO-COUPLER failure (I.e. the electronic device that
interfaces the micro-processor with the power Triac). OPTO-
COUPLER failures are more wise to return to the factory for
repair and testing.
Replacing a TRIAC BTA26 can be done easily by unwelding
and replaced at low cost, therefore to be available on stock.
To test the AC output of a TRIAC on a outlet connector is
important to test this with a electronic ballast such as a
40 Watt light-bulb for example.
An electronic volt/multi-meter is not adequate to test be-
cause a TRIAC is generally allowed to leak current to deceive
a electronic meter.
Only when necessary a complete controller card can be re-
placed. Before replacing a card make sure that the amper-
age draw on the AC-output is in relation to the operation
conditions shown as I [A] in the tabel with capacitors.
Use only slow-blow fuses as replacement for all controllers!
n/a Blower not running. Defective fuse or open/short circuit on
specific circuit.
Repair or replace fuse, open/short circuit
or replace print board.
Check fan by testing with direct current
on fan.
Replace fan if still not running.
Check if blower setting is not at B0.
Put blower setting to B1 - BA.
Failure
code
Description Possible cause Solution
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