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The Basics of Pump Motor Repairs

The dictionary defines a motor as "anything that produces or imparts motion," which is about as simple as it gets. In electrical terms, however, the definition is a bit tighter: "A machine for converting electrical energy into mechanical energy.In the context of a pool, spa, hot tub or waterfeature, that conversion results in the energy necessary to push and pull the water in and out of the vessel, its filter, plumbing, heater and anything else in the circulation system requiring hydraulic pressure.when you strive to learn about motor maintenance and repair, it’s crucial to be familiar with such definitions. Indeed, a working knowledge of a variety of motor-related terms is a useful first step along your learning curve. to that end, you’ll find below a helpful listing of basic motor terminology.

Airgap: the air space between two magnetically related Or electrically related spa parts,  such as the space between poles of a magnet or the poles of an electric motor.

Alternating current: An electrical current that alternates, flowing first with a positive polarity, followed by a negative polarity.

Capacitor: An electrical device consisting of two or more conducting plates separated from one another by insulating material and used for storing an electrical charge.

Dielectric: The insulating material that separates and insulates the conducting plates in a capacitor. It can be gas liquid, plastic, glass, paper — or a combination.

Dielectric breakdown: The failure of an insulating material to separate electrical charges. Such a breakdown occurs when the insulating material changes and conducts the electrical charge between plates.

Frequency: In electricity, the number of times alternated current changes direction during one second.frequency is measured in hertz (cycles per second)

Hertz: A unit of measurement of frequency. hertz indicates cycles per second of alternating current.

Horsepower: The conventional unit of measure for power. horsepower indicates the result of force multiplied by distance multiplied by time one horsepower (hp) equals 746 watts or 33.000 foot pounds per minute or 550 foot pounds per second.

Locked-rotor test: A test of an electric motor in which the shaft is prevented from turning while power is applied. It can, for example,be used to determine fixed and variable losses in a motor

NEMA: The National electrical Manufacturers Association.

No-load test: Operating a motor at full speed with no load to determine rotational power losses.

Rotor: The rotating part of an electric rotating machine. in a motor, it is connected to and turns the drive shaft. In in alternator or generator, the rotor is turned to produce electricty by cutting magnetic lines of force.

Service Factor: A measure of the reserve margin into a motor. Listed on the motor’s nameplate, the service factor (SE) is multiplied by the rated horsepower indicating a permissible load that can be accommodated by the motor when it is operating at its rated voltage and frequency. For example, a 1 hp motor showing a service factor of 1.35 on the nameplate can effectively deliver 1.35 h p.

Single phase: having only one alternating current or voltage in a circuit.

Stator: The stationary part of a motor that contains the laminated steel core with the winding; this is where the rotor revolves.

Torque: A force that produces a rotating or twisting action.

Triac: An electronic switch used in applications such as power switches, light dimmers and motor controls.

Voltage: Electrical pressure; the Force that causes current in an electrical conductor.

Watt: A unit of electrical powver representing the power developed in a circut by a current of 1 ampere when the voltage drop is 1 volt.

Wattmeter: An instrument for measuring electrical power.

Capacitor-start motor: An alternating current, split-phase induction motor that has a capacitor connected in series and uses an auxiliary winding for starting. The auxilary circuit disconnects when the motor is up to speed. This motor requires an internal starting switch and governor.

Permanent split capacitor motor: A single-phase electric motor that uses a phase winding in conjunction with the main winding. The phase winding is controlled by a capacitor that stays in the circut at all times and is rated for continous running. The capacitor improves starting and running power factors. This motor does not require an internal starting switch or a governor.

Split-phase motor (also known as a resistance-start motor): A single—phase induction motor that has an auxiliary winding connected in parallel with the main winding. The auxiliary winding’s magnetic position is not the same as the main winding, so it can produce the required rotating magnetic field needed for starting. This motor requires an internal starting switch and a governor.

Three-phase electric motor: A motor that operates from a three-phase power source. In three-phase power. three voltages are produced that are 120 electrical degrees apart in time. This motor has no internal starting switch.

Two-capacitor motor: An induction motor that uses one capacitor for starting and one for running. the starting capacitor is in parallel with the running capacitor as the motor is starting; at 75 percent of speed,the starting capacitor is cut out of the circuit. this type of motor is Sometimes called capacitor start/capacitor run and requires an internal starting switch and governor.

The motors that power pool and spa pumps are among the simplest devices serviced by the industry's technicians — especially when troubleshooting and repair are performed systematically. Motors used on pools and spas are small by comparison to those used in other applications — typically in the 1/2- to 2hp range — but the importance of their role in circuiation systems makes them among the most important parts of the pool/spa package. Because they are so basic a component of pool and spa service, motor repair is always a popular hands-on topic for service seminars and classes. In fact, this type oF equipment repair is usually the first step service techs take in branching out from basic service into equipment repair. And the reason is obvious: Quick, effective motor repair can provide a good monetary payoff — and fill in some spare winter hours of shop time to boot.While straightforward, motor service still requires a solid, systematic approach With that in mind, manufactors provide simple, step-by-step troubleshooting tips for service techs the rules found in the following are general enough to be applicable to most models you’ll run across on the last note: Before you examine the motor or remove its cover, remember first to turn off the electrical power at the fuse or breaker box, That precaution taken, dig in!

For some people, motor repair really means motor replacement After all, if you don’t know how to fix a broken motor, changing a malfunctioning unit may be your Only Option.For others, such as   Elias Duran, a service technician from Sepulveda, Calf., motor repair is a useful way to keep down the cost to the customer, while earning a tidy profit.Duran has been teaching the basics of motor teardown and repair for more than a decade at the Western Pool & Spa Show. Noting Duran's expertise in motor repair, P/SN asked him to demonstrate how to tear down a motor in step-wise Fashion so that the procedure could be shared with readers.He obliged, not only providing instructions on how to tear down and reassemble a motor, but also adding some troubleshooting hints and instruction on how to replace ball bearings, perhaps the most common form of motor repair.When Duran is finished with his weekly service route. his attention often turns to repairing the small electric motors that power pool and spa pumps. Be it Franklin, A.O. Smith, Emerson, General Electric or another manufacturer’s model, he is a whiz.Please note: Some slight differences may occur between different motor models. When in doubt, consult a handhook for the specific model you're repairing.

After you’ve collected the tools you’ll need and removed the motor from the pump, you are ready to begin with the process of tearing down the motor.Before starting the tear down, Duran advises there are several points you should keep in mind in approaching the ailing motor:

Always use quality replacement parts, as recommended by the motor manufacturer.

When tearing down a motor or replacing parts, never force anything — you may wind up replacing additional parts.

If you need help with a motor, take it to reputable motor-repair shop.

Be safety-conscious when working with electricity. Always be sure the motor is grounded before connecting the power. and be sure the power source is disconnected before you begin working on the motor. Also be sure you are using the correct electric voltage, whether it’s 110 or 220.

When an electric motor isn’t running, the service technician’s surest ally is an ohmmeter or, alternatively, a multimeter.Using one of these devices, it is possible to test the motor’s electrical system fully and q uickly — checking all grounds, measuring the resistance of the motor windings and overload protector,testing the capacitor and insulation, and troubleshooting the starter switch.some ohmmeters provide a true ohm value reading (usually models with digital read outs),but others feature numerical ranges that reach from R x 1 — in which the meter indicates the actual value in ohms —to R x 1K (1,000 times greater than the ohm value indicated) and R x 100K (100,000 times the indicated value in ohms).When using one of the variable-range ohmmeters for testing and troubleshooting Follow the metre manufacturer’s instructions regarding range selection for each kind of test.If your ohmmetre does not have the exact range indicated, use the next higher range.

Before making any electrical tests, review your ekectrical- safey preca utions and be sure all motor leads are disconnected from the power source.Make sure to perform a visual check of the electrical leads, wires, terminals and contacts, checking for any burned, cut, pinched, frayed or disconnected leads or wires.

Test: Set the ohmmeter on the R x 1k range. Attach one probe to the ground screw and touch the other probe to all electric terminals on the terminal board switch,capacitor and overload protector

Troubleshooting: Any reading of less than infinity on the ohmmeter indicates a ground. If any contact is grounded, check and repair all external electrical leads. If the ground is in the stator, you should replace the motor. Retest the grounds until no readings register on the ohmmeter.

Test: Set the ohmmeter on R x 1. Slip a heavy piece of paper between the points of the switch; discharge the capacitor by shorting across the terminals with an insulated screwdriver and compare the following readings with the ohmmeter, Assuming the leads function as follows:

L1 = one main winding lead
L2 = second main winding lead
L3 = third main winding lead
L4 = phase (or "start") winding lead, then: The resistance between L1 and L2 must the the same as the resistance between L2 and L3.The resistance between L3 and L5 must match the resistance between L1 and L5.

Troubleshooting: If the resistance readings for either of the two tests differ, check the external leads for repairs. The indicator may point to open for shorted windings, which will require rewinding or replacing the motor.

Test:Set the ohmmeter on R x 1K. Slip a heavy piece of paper between the points of the switch and discharge the capacitor by shorting across the terminals with an insulated screwdriver. Attach one ohmmeter lead to each capacitor terminal. Thc ohmmeter needle should move rapidly to the right. then slowly drift to the left.

Troubleshooting:Replace the capacitor if:
The capacitor does not register an ohmmeter Value.
The ohmmeter reading moves to 0 and stays there.
The ohmmeter reading remains at a high value (indicating an open circuit within the capacitor)

Test: Set the ohmmeter on R x 1 Check the resis-tan ce betwveen the overload protector terminals R& stance hetween terminals 1 and 2 (disc) should Ix approx r matelv 0. Resistance between term’ ii a’s 2 all 3 (heater) also should he approximately C
Troubleshooting: Replace the overload protector ii either resistance value execeds I ohm.

Test:Set the ohmmeter on R x 1 Attach one lead to each switch terminal:the ohmmeter reading should be 0. Flip the governor weight into the running position; the ohmmeter reading should be infinity. Visually check the starter switch and governor when the motor is running; switch contacts must be closed when the motor is at rest and should Open when the motor reaches about two thirds of full speed.

Troubleshooting:to discount absolutely that the starter switch is faulty, bypass the switch and repeat the above tests.Replace the starter switch if it appears to be faulty.

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