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34

Pump Motors

Level 2

A.O.Smith

Capacitor Start

Capacitor Run — Single Speed

SWITCH

RUN. CAP.

Summary of Contents for PT1072

Page 1: ...T PUMPS INSTALLATION TIPS REPAIR TROUBLESHOOTING OTHER MODULES INCLUDE HEATING VENTILATION AIR CONDITIONING REFRIGERATION MOTORS GENERAL PURPOSE MOTORS SPECIAL PURPOSE MOTORS PUMP MOTORS A O SMITH A O...

Page 2: ...ly 32 Single Speed Motor Typical Schematic Diagrams 33 Motor Assembly 36 How To Replace Bearings 37 Bearing Information Table 39 Recommended Tools 39 Motor Reassembly 40 2 Speed Motors 40 Start Switch...

Page 3: ...no capaci tors 2 Capacitor Start This is the most common single phase motor found on in ground pool and jet pump appli cations The starting torque is higher 150 175 of full load and starting current l...

Page 4: ...rs and Standard 778 applies to jet pump motors The motors are two pole 3450 RPM designs or two pole four pole 1725 RPM designs The two pole design is used because it runs cooler and moves more water T...

Page 5: ...load has failed you should look for other prob lems Its failure is often a symptom of another problem The pumps are designated centrifugal since the motor spins an impeller which moves the water by c...

Page 6: ...ic or velocity energy into the water As the water is propelled to the outer edge of the impeller there is a reduction in pressure at the eye of the impeller creating a vacuum figure 6 The combination...

Page 7: ...eed motor 3450 1725 for energy sav ings during low traffic periods on pool or spa motors The load on the motor is reduced drasti cally but you also do not get the turn over rate of the high speed In t...

Page 8: ...the total horse power output Find it on the motor s name plate Use this equation The total horsepower times x the service factor of the replacement motor must be equal to or greater than that of the...

Page 9: ...ted tub motors also operate on the principle of centrifugal force Pool and spa motors are two pole 3450 RPM designs The two speed versions are 3450 1725 Four pole windings are used on the low speed Th...

Page 10: ...eplate indicating a non standard mount Even though the mount is not standard per NEMA it has become standard among the pump manufactur ers Spas and jetted tubs may sometimes be sim ilar in looks and c...

Page 11: ...bearing It is not recommended that a jet pump motor be used as a replacement for a pool pump motor even though horsepower and mountings may be equivalent The pool motor will have a ground bonding lug...

Page 12: ...olt connection and 207 volts to 253 volts on the 230 volt connection At 207 volts the amps will be higher and the RPM will be approx imately 25 lower If the system is rated at 208 volts or 200 volts a...

Page 13: ...ion so that the amps may be easily checked or the connections are made so that a loop in the wire is available for checking amps If total horsepower or horsepower times ser vice factor is difficult fo...

Page 14: ...2 1 90 95 3 4 1 27 95 3 4 1 65 1 25 1 1 25 1 25 1 1 65 1 65 1 1 2 1 10 1 65 1 1 2 1 47 2 20 2 1 10 2 20 2 1 30 2 60 2 1 2 1 04 2 60 Uprated Uprated Uprated Uprated Uprated CAPACITORS It is recommende...

Page 15: ...g Most jet pumps use open drip proof motors ODP When used in a vertical application out doors a different or additional rain canopy is required A separate dog house or motor cover such as the Blue Dev...

Page 16: ...maged by the dry oper ating condition it will leak and probably allow moisture into the motor bearing Jet pumps operate on the principle of centrifu gal force The motor spins the impeller which does t...

Page 17: ...jet pumps may be configured for either shallow or deep well applications Shallow well systems use one pipe into the water source and deep well systems use two pipes One pipe provides water to operate...

Page 18: ...he amount of air pressure in the system As water is pumped air in the tank is com pressed until system pressure reaches the cut out level The most popular tanks have a bladder or diaphragm which separ...

Page 19: ...ted at twenty starts of three second duration per hour Rapid cycling causes heat to build up which may cause failure Premature wear also occurs on the start switch When a pump s flow decreases the pre...

Page 20: ...ngle voltage 115 or 230 for example or dual voltage 115 230 On original equipment 115 volt 1 3 and 1 2 HP units are common since there is enough volume to warrant a separate model with a slightly lowe...

Page 21: ...n provides many clues to help determine the cause Did the motor fail due to a defect or old age or was its failure hastened by the application or environment The application is the only place an attem...

Page 22: ...for pump motors The calculations were based on motors with the highest starting currents Larger wire sizes reduce the voltage drop at the motor in both the start and run modes A lower voltage drop mea...

Page 23: ...h operation See if there is evidence of the rotor striking the stator Check for internal corrosion cracked end frames clogged fan or other obstruction within the motor Check pump for obstructions bind...

Page 24: ...leaves lint and bugs and small lizards may plug air passages If the motor has an internal cooling fan is it intact and functioning properly Application overload In cases of flooded suc tion or positiv...

Page 25: ...ion ELECTRICAL SHOCK Check motor windings all motor wiring and capacitor for ground PROTECT AGAINST MOISTURE The open drip proof type motors discussed here may be used outside but their life expectanc...

Page 26: ...start making noise failure is imminent If the seal leaks and is not replaced the bear ings may also be ruined A new seal should be installed any time a motor is replaced A slinger or flinger should a...

Page 27: ...ge use the next higher range DIGITAL OHMMETER MULTIMETER Direct reading digital ohmmeters are readily available in the field To use this type Make sure all motor leads are disconnected from the power...

Page 28: ...r adequate wire size Look for loose terminals and connections or pitted contacts check pres sure switch and pump disconnect switch Check voltage at service entrance If not with in 10 contact power com...

Page 29: ...ed which would remove the plat ing and cause early failure They may be cleaned by wiping with a piece of cardboard or paper bag Reconnect power Start motor Visually check the action of the switch and...

Page 30: ...slightly On models with two screws turn the switch adjustment screw until the correct clearance is obtained When finished tighten the adja cent switch screw to secure the switch to the bracket Under n...

Page 31: ...d moisture could show resistance to ground below 10K and still run satisfactorily A cleaning may be in order Readings may vary from day to day depending upon the humidi ty levels Approximately 25K at...

Page 32: ...minal WINDING CONTINUITY For typical single phase dual voltage only capaci tor start single speed motor connected for 230V Set meter to R x 1 For single voltage motors check between L1 and L2 Slip a h...

Page 33: ...Attach one probe to each terminal ohmmeter needle should move rapidly to right then slowly drift to the left Low ohm reading to high ohm value If a digital meter is used readings should start low and...

Page 34: ...oblem not just a defective over load 1 2 PUMP DISASSEMBLY Wrench flats on shaft have been provided to facilitate impeller removal Insert a 7 16 open end wrench under governor assembly and hold while u...

Page 35: ...p Motors 33 Level 2 A O Smith SINGLE SPEED MOTOR TYPICAL SCHEMATIC DIAGRAMS Capacitor Start Induction Run Single Speed EXT WIRE ROUTING Dual Voltage Single Speed Capacitor Start With Voltage Change Pl...

Page 36: ...34 Pump Motors Level 2 A O Smith Capacitor Start Capacitor Run Single Speed SWITCH RUN CAP...

Page 37: ...Pump Motors 35 Level 2 A O Smith SINGLE SPEED MOTOR TYPICAL SCHEMATIC DIAGRAMS Capacitor Start or Split Phase Single Voltage on Winding Protector Capacitor not shown in schematic SWITCH...

Page 38: ...s in baffles type of protector type of flange and bearing construction When disassembling make sure you note the exact location of all com ponents so they can be reassembled in the proper order This i...

Page 39: ...ps as necessary Refer to the table for the size tube needed to install new bearing s It is important to press only on the bearing inner race The bearing will be damaged if the outer race surface is us...

Page 40: ...ng the proper size tube and a mallet or use a press Attach any other parts as used to the short shaft end Compare the rotor and shaft parts assembly shown on the previous pages with the order of assem...

Page 41: ...ions show how the bear ing installation tube is used to install new bearings RECOMMENDED TOOLS Bearing Installation Tube Dimensions In Inches 2 Bearing Dimensions A O Smith Bearing Part No 1 Outer Dia...

Page 42: ...to elaborate and exotic automatic systems Thus troubleshooting two speed systems requires an extensive knowledge of both motors and controls Two speed motors are built with and without high low switc...

Page 43: ...ufficient tension against the screw Tighten only when adjusting If the screw is loosened it should be removed and the U bracket should again be opened slightly Under no circumstances should switch con...

Page 44: ...HIGH SPEED START WHITE COMMON FROM START WINDING RED TRACER BLACK TO 3 YELLOW TO 1 4 POLE MAIN 2 POLE MAIN START CAPACITOR LOW HI YELLOW TO 5 YELLOW TO 1 TO 5 TERMINAL 1 TERMINAL 5 TERMINAL 4 TERMINAL...

Page 45: ...le windings When the control calls for high speed run the start switch automatically switches the motor to high WHITE COMMON LOW HI YELLOW TO 4 BLACK TO 5 BLACK 1 TO 5 TERMINAL 1 TERMINAL 5 TERMINAL 2...

Page 46: ...h 2 SPEED MOTORS HIGH SPEED START SCHEMATIC DIAGRAM 2 Speed for Remote Switch Operation LINE VOLTS HIGH SPEED LINE VOLTS LOW SPEED BLACK YELLOW START X Y CLOSED Z OPEN RUN X Y OPEN Z CLOSED BLACK RED...

Page 47: ...W LOW YELLOW HI LOW SWITCH PURPLE REMOVE BOTH YELLOW LEADS FROM A TERMINALAND CONNECT TO TERMINALL1 REMOVE BLACK LEAD FROM HI LOW SWITCH AND CONNECT IT TO TERMINALA LEAVE SWITCH IN CANOPYAND LEAVE PUR...

Page 48: ...L2 L1 HIGH SPEED L2 A LOW SPEED 2 SPEED MOTORS HIGH SPEED START SCHEMATIC DIAGRAMS AND RECONNECTION INSTRUCTIONS FOR REMOTE OPERATION 2 Speed with Hi Low Switch Mounted in External Box START BLACK CAP...

Page 49: ...FR 2 Electrical Determine operating voltage phase max amps and hertz or cycles 3 Horsepower Multiply nameplate horsepower times the service factor to find total horsepower The total horsepower of the...

Page 50: ...lace ment C Always install a new seal when reassembling a pump or installing a replacement motor D Be sure the motor is connected for the system voltage Most A O Smith dual voltage pump motors are fac...

Page 51: ...If an external motor cover is used be certain it does not trap moisture or allow cooling air to recirculate D Don t store or use chemicals close to the motor E A running motor that is too hot to touch...

Page 52: ...531 NORTH FOURTH STREET TIPP CITY OH 45371 937 667 6800 FAX 937 667 5873 www aosmithmotors com 2001 A O Smith Corporation Bulletin 3300 3 01...

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