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27

Fuse and Circuit Breaker Sizing

The following information applies to compressor motor branch circuit, short circuit and ground 
fault protection only.

NEC Article 440

Hermetic compressors should be protected in accordance with Article 440 of the National 
Electric Code which calls for substantially larger circuit breakers than are required for open 
type motors.

Maximum Size

The maximum size of the fuse or circuit breaker used to protect against short circuit and/
or ground fault of a unit utilizing a hermetic compressor shall be 

no more than

 the sum of 

225% of the compressor Rated Load Amps (RLA) as marked on the system serial label, 
plus the RLA values of each of the other motors which use the same branch circuit.

Minimum Size

The minimum value of the fuse or circuit breaker shall be 

no less than

 175% of the RLA 

of  the  compressor.  The  interpretations  and  directions  given  above  apply  only  to  single 
branch power supplies and do NOT pertain to any plug-in type of appliances.  Also, see 
“PSC Motor Starting” on pages 17-18.

Содержание AH5540E

Страница 1: ...Hermetic Compressor Service Handbook Wholesale Distribution North America...

Страница 2: ......

Страница 3: ...Hermetic Compressor Service Handbook Ann Arbor MI 48108 REV 3 11...

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Страница 5: ...formation in this Service Handbook is generally limited to the compressor and to items and conditions affecting the installation operation and servicing of the compressor It is not designed to be a te...

Страница 6: ...itor Overheating 7 System Evacuation 7 Follow the Labels 8 Model and Application 9 Compressor Model Number Codes 10 Condensing Unit Model Number Codes 11 Serial Label Information 12 Basic Application...

Страница 7: ...placing Compressors in Water Utilizing Systems Preventing Explosions 87 Operation 89 Control of Liquid Migration to the Compressor During Shutdown 90 Crankcase Heaters 93 Starting a System with Liquid...

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Страница 9: ...Chapter 1 General Service Safety Precautions...

Страница 10: ...and Electrocution Precautions To reduce the risk of electrocution or serious burns or death from terminal venting with ignition Be alert for sounds of arcing sizzling sputtering or popping inside the...

Страница 11: ...use extreme caution to avoid electric shock FIGURE 1 1 Compressor with 1 protective cover and 2 bale strap removed to show 3 hermetic terminal FIGURE 1 2 Close up view of hermetic terminal show ing in...

Страница 12: ...bite cause a fire if a torch is used to disconnect tubing expose the service person to toxic gas To avoid serious injury or death be sure to remove and recover all refrigerant before removing the comp...

Страница 13: ...system Do not operate the compressor without charge in the system Operating the compressor without a charge in the system can damage the hermetic terminal As always to avoid serious injury or death fr...

Страница 14: ...xplosion of the compressor or other system components Service Procedures In light of the risk of explosion be especially alert for signs of water leaking into the refrig erant side of the system Whene...

Страница 15: ...he heat exchanger The entire system must be replaced See Replacing a Single wall Water utilizing System on page 33 If you do not find any indication of a history of loss of charge without detection of...

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Страница 17: ...Chapter 2 Model and Application...

Страница 18: ...nj 10 F High G Low Vapor Inj 10 F High In this example 4 total digits with the first two 40 or 4 000 BTU capacity Primary Refrigerants A R12 B R410A C R407C E R22 J R502 U R290 M R600a Y R134a Z R404A...

Страница 19: ...ing Units HL Outdoor Condensing Unit with Options Celseon Air Cooled Units CB Std Unit W EC Fan Motor Sweat Conns Power Cord Receiver Tank CC Std Unit W EC Fan Motor Sweat Conns Power Cord Receiver Ta...

Страница 20: ...The only source for complete compressor information is on the compressor serial label On earlier compressors the serial plate is usually spot welded on the upper housing of the compressor For current...

Страница 21: ...e using R 404A in a compressor designed for R 134a can lead to higher operating pressures that can overload the bearings and overwork the motor Use of a refrigerant other than the serial label refrige...

Страница 22: ......

Страница 23: ...Chapter 3 Compressor Motor and Component...

Страница 24: ...ral lel with each other and in series with the motor start winding see Figure 3 4 This motor has high starting torque runs efficiently and is used on many refrigeration and air condi tioning applicati...

Страница 25: ...ting and operating characteristics and the field conditions that can affect it The following conditions affect PSC motor starting Low voltage Reduces motor start ing and running torque A 10 voltage dr...

Страница 26: ...oo small will cause nuisance tripping see Fuse and Circuit Breaker Sizing on page 27 If the fuse or circuit breaker trips see Identifying Compressor Electrical Problems on pages 40 41 for electrical t...

Страница 27: ...see Figure 3 8 reacts to excess temperature and or excess current draw by flexing downward and disconnecting the compressor from the power source Figures 3 9 and 3 10 show the installation of a therma...

Страница 28: ...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 resi...

Страница 29: ...te starting device is placed in series with the start winding and normally has a very low resistance Upon startup as current starts to flow to the start winding the resistance rapidly rises to a very...

Страница 30: ...potential relays with hermetic compressors A large number of these have been used on air conditioning applications but there are also many other applications Since there are many variations with regar...

Страница 31: ...lay Code 128 12 2 13 3 5 C A POTENTIAL RELAY TYPE TYPE OF BRACKET CONTACT STRUCTURE TERMINALS TYPE AND LOCATION COIL GROUP CONTINUOUS VOLTAGE MOUNTING POSITION CALIBRATION HOT PICK UP VOLTS CUSTOMER S...

Страница 32: ...lay from functioning Capacitor fail ure and or starting winding failure could result To eliminate this Tecumseh Products Company start capacitors are equipped with bleeder resistors wired across the c...

Страница 33: ...amount and the limits are shown in Table 3 5 Remember the voltage rating of all capacitors must be the same or greater than the original rating If the voltage rating is not known use 370 volt capacit...

Страница 34: ...ssor models have terminal pin identification embossed on the protective terminal cover While the protective terminal cover may identify the terminal pins it is primarily designed to reduce the risk of...

Страница 35: ...cuit breaker used to protect against short circuit and or ground fault of a unit utilizing a hermetic compressor shall be no more than the sum of 225 of the compressor Rated Load Amps RLA as marked on...

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Страница 37: ...Chapter 4 Servicing...

Страница 38: ...30 SERVICE HANDBOOK...

Страница 39: ...ver reset a breaker or replace a fuse without first checking for a ground fault also known as a short circuit to ground Before Servicing Servicing Introduction to Servicing This chapter provides infor...

Страница 40: ...refrig erant side of the system Whenever servicing or troubleshooting a water utilizing system always check to see if it has either a pressure relief valve or a high pressure cut out as previously de...

Страница 41: ...replaced See Replacing a Single wall Water utilizing System below If water does not come out of the process valve there is still a possibility that some water has leaked into the refrigerant side of t...

Страница 42: ...warranty see Is Your Compressor Eligible for Return Under Warranty on page 70 Table 4 1 Troubleshooting Chart Complaint Possible Causes Response Compressor will not start no hum System component not...

Страница 43: ...40 41 Liquid refrigerant in compres sor Add crankcase heater and a suction line accumulator It is difficult to determine how liquid refrigerant got into the compressor A crankcase heater along with a...

Страница 44: ...extra sources of current passing through thermal protector such as fan motors pumps Refer to the OEM service infor mation 2 See Identifying Compres sor Electrical Problems on pages 40 41 Low voltage...

Страница 45: ...Water leak into refrigerant side of a water utilizing system 1 3 Refer to the OEM ser vice information 4 See Servicing or Troubleshooting Water Utilizing Systems Preventing Explosions on pages 32 33 A...

Страница 46: ...o high System problems such as 1 Control setting too high 2 Expansion device restrict ed or too small 3 Cooling coils too small 4 Inadequate air circulation Refer to the OEM service infor mation Water...

Страница 47: ...r or liquid shut off king valve partially closed Refer to the OEM service infor mation Water leak into refrigerant side of a water utilizing system System rattles or vibrates dur ing operation Loose p...

Страница 48: ...alled terminal venting with ignition To reduce the risk of electrocution serious burns or death from terminal venting with igni tion Be alert for sounds of arcing sputtering or popping inside the comp...

Страница 49: ...ad separately If a ground fault does not exist leave the power off and all external components discon nected from the terminal pins Check for continuity and proper resistance using the pro cedure on p...

Страница 50: ...erminal pins Leg1 Leg2 Leg2 Leg3 and Leg1 Leg3 If there is no continuity replace the compressor See System Cleanup and Compressor Replacement After Compressor Failure on pages 83 86 Step Three Measure...

Страница 51: ...for the compressor you are servicing For more information on Compressor motor types see Single phase Compressor Motor Types on pages 16 17 Thermal protectors see Hermetic Compressor Thermal Protector...

Страница 52: ...he actual relay to locate the terminals If replacement parts are needed refer to the Tecumseh Electrical Service Parts Guide Book for information on proper replacement parts or call Tecumseh Products...

Страница 53: ...inal con nection If there is no continuity then the thermal protector may be tripped Wait for the protector to cool off and close This may take more than an hour Check continuity gain If there is no c...

Страница 54: ...relay to locate the terminals If replacement parts are needed refer to the Tecumseh Electrical Service Parts Guide Book for information on proper replacement parts or call Tecumseh Products Company at...

Страница 55: ...device Step 3 Check Wired in PTC Relay Check the relay by measuring continuity between the pin holes where the R and S pins on the compressor are inserted If there is no continuity the relay may be op...

Страница 56: ...s on the actual relay to locate the terminals If replacement parts are needed refer to the Tecumseh Electrical Service Parts Guide Book for information on proper replacement parts or call Tecumseh Pro...

Страница 57: ...thermal protector line 1 and compressor terminal con nection If there is no continuity then the thermal protector may be tripped Wait for the protector to cool off and close This may take more than a...

Страница 58: ...o locate the terminals If replacement parts are needed refer to the Tecumseh Electrical Service Parts Guide Book for information on proper replacement parts or call Tecumseh Products Company at 1 800...

Страница 59: ...ntacts are closed when they should be open Replace the current relay Relay terminals 2 and M If there is no continuity replace the current relay Step 5 Check Start Capacitor CAUTION using a 20 000 ohm...

Страница 60: ...or low pressure cut out For more information on troubleshooting the system components refer to the OEM service information Step 6 Replace Current Relay If all above tests prove satisfactory there is n...

Страница 61: ...t parts are needed refer to the Tecumseh Electrical Service Parts Guide Book for information on proper replacement parts or call Tecumseh Products Company at 1 800 211 3427 Relay Potential Compressor...

Страница 62: ...the protector Step 4 Check Protector Wiring Confirm that there is continuity between The power input terminal on the thermal protector and 5 on relay The protector common lead wire and C Step 5 Check...

Страница 63: ...relay Prolonged operation on start cycle due to low voltage Determine if the line voltage is too low less than 90 of rated voltage Prolonged operation on start cycle due to incorrect relay Replace wi...

Страница 64: ...parts are needed refer to the Tecumseh Electrical Service Parts Guide Book for information on proper replacement parts or call Tecumseh Products Company at 1 800 211 3427 Rela y Potential Compressor U...

Страница 65: ...r high or low pressure cut out For more information on troubleshooting the thermal protector see Step 5 For troubleshooting the system components refer to the OEM service information Vibration due to...

Страница 66: ...Prolonged operation on start cycle due to starting load too high Refer to the OEM service information to use pump down arrangement if necessary Excessive short cycling Short cycling can be caused by p...

Страница 67: ...Company at 1 800 211 3427 FIGURE 4 9 CSR compressor motor type with internal thermal protector with start winding protection potential relay and run and start capacitors FIGURE 4 8 CSR compressor mot...

Страница 68: ...the system Use a capacitance meter to check capacitor Capaci tance should be 10 of the marked capacitor value As an alternative check the run capacitor by measuring continuity across the capacitor te...

Страница 69: ...perly include Use of incorrect start capacitor Replace with proper start capacitor The relay contacts are not working properly Replace the relay Prolonged operation on start cycle due to low voltage D...

Страница 70: ...the Tecumseh Electrical Service Parts Guide Book for information on proper replacement parts or call Tecumseh Products Company at 1 800 211 3427 FIGURE 4 10 PSC compressor motor with external thermal...

Страница 71: ...ng devices and risk of electric shock Disconnect the run capacitor from the system Use a capacitance meter to check capacitor Capacitance should be 10 of the marked capacitor value As an alternative c...

Страница 72: ...eeded refer to the Tecumseh Electrical Service Parts Guide Book for information on proper replacement parts or call Tecumseh Products Company at 1 800 211 3427 FIGURE 4 12 PSC compressor motor type wi...

Страница 73: ...is no continuity replace the compressor Step 3 Check Run Capacitor CAUTION using a 20 000 ohm resistor discharge the capacitor before removing it from the system to avoid damage to measuring devices...

Страница 74: ...he terminals If replacement parts are needed refer to the Tecumseh Electrical Service Parts Guide Book for information on proper replacement parts or call Tecumseh Products Company at 1 800 211 3427 O...

Страница 75: ...If there is continuity then the run capacitor is shorted and needs to be replaced Rx100 000 scale If there is no needle deflection on an analog meter or if a digital meter indicates infinite resistan...

Страница 76: ...cate the terminals If replacement parts are needed refer to the Tecumseh Electrical Service Parts Guide Book for information on proper replacement parts or call Tecumseh Products Company at 1 800 211...

Страница 77: ...eplaced Rx100 000 scale If there is no needle deflection on an analog meter or if a digital meter indicates infinite resistance then the run capacitor is open and needs to be replaced Possible reasons...

Страница 78: ...essor does not pump adequately it must be replaced with no further testing Is Your Compressor Eligible for Return Under Warranty Authorized Tecumseh wholesalers are asked to test every in warranty com...

Страница 79: ...71...

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Страница 81: ...Chapter 5 Installation and Replacement...

Страница 82: ...or the suction connection may be used for processing the system Identification of compressor connections can usually be accomplished without difficulty however occasionally some question arises concer...

Страница 83: ...75 FIGURE 5 1 cont Standard discharge tubing arrangements AK Discharge Tube Discharge Tube Discharge Tube Discharge Tube Discharge Tube Discharge Tube AJ AH AV AZ AN AG AB RK RG...

Страница 84: ...e case of a flooded type evaporator bottom feed top suction header large inter nal volume low refrigerant oil velocities it is necessary to maintain a liquid spillover into the suction line so as to r...

Страница 85: ...16 3 8 3 8 1 2 1 2 3 8 12 000 1 2 1 2 5 8 5 8 1 2 1 4 5 16 5 16 3 8 5 16 3 8 1 2 1 2 1 2 3 8 18 000 1 2 5 8 5 8 3 4 5 8 1 4 5 16 3 8 3 8 3 8 3 8 1 2 1 2 5 8 3 8 24 000 5 8 5 8 3 4 7 8 3 4 5 16 3 8 3 8...

Страница 86: ...1 8 5 16 3 8 1 2 1 2 1 2 1 2 5 8 3 4 3 4 5 8 48 000 7 8 1 1 8 1 1 8 1 3 8 1 1 8 3 8 1 2 1 2 5 8 5 8 5 8 5 8 3 4 7 8 3 4 Table 5 3 R 134a Refrigerant Line Sizes 45 F Evap Temp 65 F Suction Vapor Temp 1...

Страница 87: ...000 5 8 3 4 7 8 1 1 8 7 8 1 4 5 16 3 8 3 8 5 16 3 8 1 2 1 2 1 2 3 8 18 000 3 4 7 8 1 1 8 1 1 8 7 8 5 16 3 8 3 8 1 2 3 8 3 8 1 2 5 8 5 8 1 2 Table 5 5 R134a Refrigerant Line Sizes 10 F Evap Temp 40 F...

Страница 88: ...6 5 16 3 8 5 16 5 16 3 8 3 8 1 2 5 16 10 000 1 2 1 2 5 8 5 8 1 2 1 4 5 16 5 16 3 8 3 8 5 16 3 8 1 2 1 2 3 8 12 000 1 2 1 2 5 8 3 4 1 2 1 4 5 16 3 8 3 8 3 8 3 8 1 2 1 2 1 2 3 8 18 000 1 2 5 8 3 4 3 4 5...

Страница 89: ...2 5 8 5 8 1 2 5 8 3 4 3 4 5 8 48 000 7 8 1 1 8 1 1 8 1 3 8 1 1 8 1 2 1 2 5 8 5 8 3 4 5 8 3 4 3 4 7 8 3 4 60 000 1 1 8 1 1 8 1 3 8 1 3 8 1 3 8 1 2 1 2 5 8 5 8 7 8 5 8 3 4 7 8 1 1 8 7 8 Table 5 8 R 404A...

Страница 90: ...rn gas temperatures to the compressor 2 To prevent oxidation and scale forming inside the tubes it is good practice to flow dry nitrogen through the tubing during the soldering operations A light flow...

Страница 91: ...upper housing sweating indicating that liquid refrigerant is reaching the compressor Is the return gas temperature at the compressor within proper limits for the application i e not too low to cause f...

Страница 92: ...rier immediately upstream of the compressor The filter drier when permanently installed in a clean system or as initially installed in a dirty system must have a pressure drop not more than listed in...

Страница 93: ...e Drop After the system has been operating for an hour or so measure the pressure drop across the suction line filter drier In the case of Compressor Housing Contamination little change should be note...

Страница 94: ...l may be slowly transferred to the beaker of the acid test kit as available from several manufac turers A reading of less than 0 05 acid number is an indication that the system is free of acid A readi...

Страница 95: ...ystems that have single wall heat exchangers may present a risk of explosion Such systems may include water source heat pump air conditioning systems and water cooling systems such as icemakers water...

Страница 96: ......

Страница 97: ...Liquid refrigerant migration to compressor FIGURE 6 1 Chapter 6 Operation...

Страница 98: ...boratories of Tecumseh Products Com pany A five ton split air conditioning system was used with a four inch sign glass installed in the compressor housing The condensing unit and evaporator sections w...

Страница 99: ...econds after start up violent foaming action fill sight glass as re frigerant boils away taking oil charge with it FIGURE 6 3 More than 60 seconds after start up oil level is well below normal operati...

Страница 100: ...odback under certain conditions while operating This condition can be controlled by the application of a suction line accumulator Crankcase heat does nothing to prevent liquid floodback and an accumul...

Страница 101: ...F The immersion type heater is factory assembled and is presently used with AB AW AG AV and AN compressors It is self regulating and energy efficient In the run capacitance off cycle heat method used...

Страница 102: ...ne to two seconds then wait 1 to 2 minutes After 3 or 4 jogs apply power continuously WARNING Jogging a compressor that has an electrical problem can increase the likelihood of terminal venting To red...

Страница 103: ...in an accumulation of the refrigerant under the oil see Figure 6 10 Thus when the compressor is started the first liquid to be pumped to the bearings will probably be refrigerant not oil Even if this...

Страница 104: ...6 10 Five seconds after start up violent foaming action fills sight glass as refrigerant boils away taking the oil charge with it FIGURE 6 11 More than 60 seconds after start up oil level is well belo...

Страница 105: ...mpressor during periods of shutdown This condition can be controlled by the application of a crankcase heater A suction line accumulator does nothing to prevent liquid migration and a crankcase heater...

Страница 106: ...nts such as evaporator temperature and capacity in tons of refrigeration These factors were considered in the design and testing of the accumulator On older systems if the system refrigerant charge is...

Страница 107: ...in refrigeration systems The IPR valve may also open to relieve hydraulic pres sures in the event of slugging This is apt to occur on startup if refrigerant has been allowed to mi grate to the compre...

Страница 108: ......

Страница 109: ...Appendix...

Страница 110: ...trolled by the pressure differential across the expansion device or in the case of a thermostatic expansion valve TEV by the amount of superheat of the suction gas Thus the TEV shown requires its sens...

Страница 111: ...ompressor Discharge Pressure Cutout Crankcase Heater LO HI Evaporator Fan Low Pressure Side Evaporator Accumulator Thermostatic Expansion Valve or Capillary Tube TEV Sensin Bulb Heat Exchanger Receive...

Страница 112: ...s Refrigerant gas surrounds the compressor crankcase and motor as it is drawn through the compressor housing and into the cylinder s through the suction muffler and suction valves As the gas is pressu...

Страница 113: ...105 Reciprocating Compressor FIGURE A 2 Internal view of typical air conditioning compressor...

Страница 114: ...heat exchange length Capillary Tube Length OD Evaporator Temperature F Refrigerant Btu h per circuit 10 20 45 22 500 19 ft 0 026 18 ft 0 026 17 ft 0 026 750 12 ft 0 028 11 ft 0 028 10 ft 0 028 1 000 1...

Страница 115: ...e same capacity as 16 ft of 0 031 capillary 404A 507 500 17 ft 0 031 18 ft 0 031 19 ft 0 031 750 16 ft 0 036 17 ft 0 036 18 ft 0 036 1 000 9 ft 0 036 9 ft 0 036 10 ft 0 036 1 250 12 ft 0 042 13 ft 0 0...

Страница 116: ...be taken not to exceed the oil charge amounts specified See Refrigerant Line Sizes on pages 76 81 If the correct oil charge is in doubt please obtain assistance from your Tecumseh Technical Service R...

Страница 117: ...5 Lubrax BR 069C EX 4 4 Lubrax ALP 415 LCR 4 4 Naphthenic Paraffinic Sonneborn Witco LP 200 3 3 3 3 Penreco Sontex 200LT A LT 3 3 3 3 Paraffinic Total Oil Company 68CST 6 Petrobas CP 68 RAD 6 Polyol E...

Страница 118: ...110 SERVICE HANDBOOK Notes...

Страница 119: ......

Страница 120: ...of arcing sizzling sputtering or popping inside the compressor IMMEDIATELY GET AWAY if you hear these sounds Disconnect ALL electrical power before removing the protective thermal cover Never energiz...

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