AUX air conditioner service manual
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winding touching shell can also occur in three phase motor. Check the faults with universal meter.
For star- type connection motor, resistance can be measured individually; for triangle- type connection
motor, three windings shall be disconnected before resistance values are measured.
4. Inspection of switches and components of appliances
(1)Inspection of selection switch
Check corresponding contact points for different functions with universal meter, if, two connection
points conduct, resistance shall be zero; two connection points don’t conduct, resistance is infinitely
great, otherwise, selection switch has some problems.
(2)Inspection of temperature controller
① Expansion bag is broken, and temperature sensitivity gas leaks, so expansion bag doesn’t expand in
response to the change of ambient temperature, and therefore, fails to act with linked pole. Check
method: check the switch on and switch off points with universal meter, and turn the temperature
setting button at the same time. If controller fails to respond, it proves that expansion bag is broken
and temperature controller needs to be replaced with new one.
② Electronic contact points fail to contact well. If temperature changes regularly and in a large scale,
it will cause frequent startup and stop of compressor and also contact points contact and break time
and again , and contact point surface will be burned and create carbon layer which stops electrical
conduct. Contact points are in the position of switch on, but fail to connect with power. Check method:
clean contact points with absolute alcohol, and check the conduct condition of temperature controller
with universal meter when it is in the position of “switch on”.
③ Tension of offsetting spring is not enough. When pressure temperature sensitive gas in expansion
bag decreases and fails to push the linked pole back. Offsetting spring shall be replaced with a new
one.
④ There’re some burrs or other dirt on the surface of electrical contactors which cause contactors
failing to break off. Abrade the burrs with 0# sand paper and make the contactor surface smooth.
(3)Inspection of protection relay
In normal condition, contactors of protection relay are closed, and check with universal meter,
contactors shall be in conducting situation, or the relay shall be replaced.
(4)Check of running capacitor
Remove a handle of capacitor to be tested, check resistance of two ends of capacitor with universal
meter. In the normal condition, index finger of universal meter swings back rapidly and then rises to
infinitely great. If index finger doesn’t move and resistance remains infinitely great, capacitor has
broken off; if index finger swings to “0” and stop moving and resistance is zero, capacitor has
disrupted; if resistance remains at certain value, capacitor leaks.
(5)Check of transistor
① Check of diode capacity
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