Truck/Trailer Refrigeration Unit - Sunbelt Transport Refrigeration

4.26 SINGLE PHASE ALTERNATOR(GENERATOR) -- TRUCKThe single phase alternator is mounted under thecompressor. The belt drive arrangement ensures thatwhen the diesel engine is in high speed, the alternatordelivers 240 vac 60Hz and when the diesel engine is in lowspeed the generator delivers 240 vac 50Hz.The alternator has a brushless compound excitation,using an auxiliary phase capacitor to provide the selfexcitation. The alternator has only one rotatingcomponent, no electronic controls and sealed-for-lifebearings, combining simplicity with reliability.b. Fault Finding Parts to be Checked --Without Loada. Checking Capacitor1. Unscrew top plastic cover.2. Disconnect capacitor wires. Connect capacitorto a main voltage with a switch and an ammeter to readcurrent (see table below).Capacitor MF 220/50 Hz IA 240/60 Hz IA12 0.83 1.08Fault Cause Action to takeNovoltagewithnoloadwhenstarting Loss of residual magnetism Apply a battery 4.5 V to capacitor terminals.Load alternator and run engine abovenominal speed for a few seconds.Defective capacitorChange capacitorRotor diode out of order or short circuit Change 2 diodes on rotorWinding short circuit or looseCheck resistance of coilsconnectionsVoltage with no load less than 80% of Speed of engine low Set engine speed Refer to 1.2nominal voltage 1 rotor diode out of order or short circuit Change 2 diodes on rotorshort circuit in windingCheck resistance of coilsTo high Voltage with no load Speed of engine high Set engine speed Refer to 1.2c. Fault Finding Parts to be Checked --With LoadFault Cause Action to takeCorrect voltage with no load, low voltage Rotor diode out of order or short circuit Change 2 diodes on rotorwith loadCheck engineThe engine slows down or stallsCheck value of loadExcessive heat (over heating) Ventilator holes partially blocked Dismantle and clean4-23 62-02884