ALTROZ SERVICE MANUAL

HVAC 15 The moving scroll rolls and slides in small circular movement with a small friction loss, ensuring smooth operation even during start-up. COMPRESSOR RELAY Compressor relay is located in the MDU ( Main distri- bution Unit) located in the engine compartment which is used to operate the compressor magnetic clutch. The magnetic clutch continues to operate as long as air conditioner is under operation. Once the air conditioner is put in OFF condition, the compres- sor relay gets cut off and the magnetic clutch gets disengaged from the compressor. The cut - in and cut - off of relay is governed by the ENGINE ECU. The HVAC control unit controls the compressor ON/OFF indirectly by sending ON/OFF request to the EMS ECU. MAGNETIC CLUTCH SPECIFICATION NOMINAL VOLTAGE 12V DC POWER CONSUMP- TION 35W BELT TYPE V – RIBBED BELT (5 PK) AIR GAP 0.25 TO 0.50 mm DIRECTION OF ROTATION CLOCKWISE WEIGHT 1.5 Kg WITHSTAND VOLTAGE AC 500V X 1Min PULLEY DIAMETER Ø110 Magnetic clutch is used to connect and disconnect the compressor from the engine. Main components are stator, rotor, and pressure plate. PRINCIPLE When the current is fed to the coil magnetic force is generated in iron, which attracts any other iron. CONSTRUCTION A magnetic clutch consists of a stator, rotor with pul- ley, and pressure plate to engage the drive pulley and compressor magnetically. The stator is fixed on the compressor housing, and the pressure plate is attached to the compressor shaft. Two ball bearings are used between the inner surface of the rotor and the front housing of the compressor. OPERATION Whenever the engine is operating, the pulley is rotat- ing since it is connected to the crankshaft by a belt, but the compressor does not operate until the clutch is energized. When the air conditioning system is switched ON, the ECU generates a signal for ener- gizing the compressor. The electromagnet attracts the pressure plate and pulls the plate against the friction facings on the pulley. The friction between the facing and plate causes the clutch assembly to rotate as a unit, and drive the compressor.