Tecumseh AH5540E, Service Handbook

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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.