A GLOSSARY OF MOTOR
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, its 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, youll find below a helpful listing of basic motor
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.
An electrical current that alternates, flowing first with a positive polarity,
followed by a negative polarity.
electrical device consisting of two or more conducting plates separated from one another
by insulating material and used for storing an electrical charge.
insulating material that separates and insulates the conducting plates in a capacitor. It
can be gas liquid, plastic, glass, paper or a combination.
The failure of an insulating material to separate electrical charges. Such a
breakdown occurs when the insulating material changes and conducts the electrical charge
electricity, the number of times alternated current changes direction during one
second.frequency is measured in hertz (cycles per second)
unit of measurement of frequency. hertz indicates cycles per second of alternating
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.
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
National electrical Manufacturers Association.
Operating a motor at full speed with no load to determine rotational power losses.
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.
measure of the reserve margin into a motor. Listed on the motors 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.
only one alternating current or voltage in a circuit.
stationary part of a motor that contains the laminated steel core with the winding; this
is where the rotor revolves.
force that produces a rotating or twisting action.
electronic switch used in applications such as power switches, light dimmers and motor
pressure; the Force that causes current in an electrical conductor.
unit of electrical powver representing the power developed in a circut by a current of 1
ampere when the voltage drop is 1 volt.
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 singlephase induction motor that has an
auxiliary winding connected in parallel with the main winding. The auxiliary
windings 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
THE BASIC MOTOR DIAGNOSIS
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 youll run across on the route.one
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!
MOTORS AT THE WORKBENCH
For some people, motor repair really means
motor replacement After all, if you dont 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
manufacturers 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
TEARDOWN AND REPAIR
After youve collected the tools
youll 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 its 110 or 220.
ELECTRICTY AND MOTOR
When an electric motor isnt running, the
service technicians surest ally is an ohmmeter or, alternatively, a multimeter.Using
one of these devices, it is possible to test the motors 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
manufacturers 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
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
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.
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.
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
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 as 2 all 3 (heater) also should he approximately C
Troubleshooting: Replace the overload protector ii either resistance value execeds I ohm.
STARTER SWITCH (OPTIONAL)
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.
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.