Tecumseh AH5540E - Page 28

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SERVICE HANDBOOK
Table 3-3: Facts About Thermal Protectors
External Line-Break Thermal Protectors
•CurrentlyusedonallAE,AK,AZ,TP,TH,TW,HG,RK,RG,RN,andAJmodels.
•Sensemotorcurrentandhousingtemperatureorcombinationthereof
•Breaklinecurrentwhentripped
•Generallydonotprotectagainstlossofcharge
•When,bydesign,noairflowpassesoverhousing, aspecial“static”thermalprotector
must be used
•Aredesignedforspecificcompressorsandtheirintendedapplication.Makenosubstitutions
•Willnotprotectmotorifcompressorisoperatedoutsideitsevaporatortemperaturerange
Internal Line-Break Thermal Protectors
•CurrentlyusedonallAH,AB,AV,AG,AW,VSandmostAN,SAandSFmodels
•Sensemotorcurrentandmotorwindingtemperatureorcombinationthereof
•Breaklinecurrentwhentripped
•Generallyprotectagainstlossofcharge
•Willnotprotectmotorifcompressorifoperatedoutsideitsevaporatortemperaturerange
•Notrepairableorreplaceable
Line Voltage-Electronic Protection Module (note - for more specific details consult an authorized
wholesaler)
•OriginallyusedonsomeANandSFmodels
• Employs use of solid state temperature sensors in motor windings and compressor
discharge muffler
•Sensorresistancevalueschangewithtemperaturevariations
•Modulewillinterruptpowertothecontactorcoilwhenresistancevaluesofsensorsexceed
the specified range. This power interruption thus stops the compressor motor
•Moduleprovidesprotectionagainst
– Abnormal locked rotor conditions
– Loss of refrigerant
– High compressor discharge temperatures
– Excessive current conditions
– Time delays of 3 to 5 minutes occur on power interruption or sensor trip
Internal Thermal Protectors
Internal thermal protectors are completely internal and tamper-proof. They cannot be bypassed.
Single-phase Motor Thermal Protectors
Internal thermal protectors detect excess heat and/or current draw. They are located in the fol-
lowing single-phase motors: AB, AW, AN, AH, AV, AG, and VS.
Three-phase Motor Thermal Protectors
The 31HM, 32HM, 34HM and 35HM on-winding motor protectors are 3-phase line break, au-
tomatic reset devices wired in series with each phase at the neutral point and mounted on the
windings. They are used in AB, AW, AN, AG, AV and VS models.