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ManualsBrandsA. O. Smith ManualsElectric MotorsA.O. Smith SQ1102 1 HP, 3450 RPM, 1.65 Service Factor, 48Y Frame, Capacitor Start, ODP Enclosure, Square Flange Pool Motor

Pump Motors

A.O.Smith

Tro u b l e s h o o t i n g

T h e re is not a single listing of motor trouble shoot-

ing pro c e d u res to be followed in a given ord e r. The

p ro c e d u res will differ depending on the situation.

As with anything dealing with electricity, personal

safety is of prime concern. Before you even touch

the motor, MAKE SURE THE POWER IS OFF.

Always turn the power off at the electric service

fuse or breaker box. To prevent electrical shock, use

a meter to check for electrical shorts and be sure

the motor is securely grounded and bonded in

conformity with local codes. Do not work on

electrical devices if water or moist conditions are

p resent and cannot be avoided.

If the motor is not operating pro p e r l y, refer to the

f o l l o w i n g :

Motor fails to start (makes no sound)

• Check the obvious first. A r e the power switch

and timer on?

• Check for blown fuse or circuit bre a k e r. If fuses

a r e used be sure fuses are the proper size or type.

• WITH THE POWER OFF, check all connections

on the terminal board. Verify they are correct by

consulting the wiring diagram on the motor.

Make sure all connections are tight including

the ground wire.

• Check the voltage at the terminal board after

first turning the power back on. Be sure to

TURN THE POWER BACK OFF after complet-

ing this step. Note: Voltage at motor terminals

should be + or – 10% of the voltage on the

nameplate. If the voltage is high, contact the

local Power Company. If the voltage is low

check the wire size of the power line from the

electric box to the motor.

Checklist

Summary of content (11 pages)

PAGE 1
26 Pump Motors Troubleshooting There is not a single listing of motor trouble shooting pro c e d u res to be followed in a given ord e r. The pro c e d u res will differ depending on the situation. As with anything dealing with electricity, personal safety is of prime concern. Before you even touch the motor, MAKE SURE THE POWER IS OFF. Always turn the power off at the electric service fuse or breaker box.
PAGE 2
Pump Motors • Check for overloading from other appliances on the same circuit as the motor. • Inspect motor windings for continuity. • Protector tripped – wait until the motor cools down then restart – check protector for continuity 27 Motor starts but shuts down (thermal overload protection) • Check the voltage at motor terminal. If it is too high call the local Power Company. • Check amperage. If high, find out if the pump impeller was recently replaced (it could be sized i n c o r rectly).
PAGE 3
28 Pump Motors • Compare connections to wiring diagram. Make sure motor is connected correctly for applied voltage. • Low or high voltage. Voltage should be + or – 10% of nameplated voltage. If it is higher that +10% call the local power company. If lower than –10% of the nameplated voltage check wire size from the service fuse box or circuit bre a k e r.
PAGE 4
Pump Motors • Misapplication. Make sure the motor is not undersized. Remember that total horsepower is horsepower times service factor. The total horsepower must be equal to or greater than the pump/impeller rating. • Check the motor start switch and governor (if applicable) to make sure it is adjusted properly and is operational. This section explains how to use test equipment.
PAGE 5
30 Pump Motors Digital Ohmmeter/Multimeter Direct reading digital ohmmeters are readily available in the field. To use this type: • Make sure the power is off. • Read instruction manual for the meter. • You do not have to set the ohmmeter to a particular scale as the meter displays the ohm value up to maximum capability of the meter. • Install probes and take resistance readings in the normal manner. Ammeter and Voltmeter Voltmeter Readings: Install leads in bottom of ammeter.
PAGE 6
31 Pump Motors Voltage Check • Make sure power is off. • Determine motor voltage and set meter • Reconnect power • Start the motor Electrical Checks Caution: All wires are live (hot) so use extensive care. Touch one probe to L1 and the other to L2. Voltage reading to be within 10% of nameplate voltage, i.e. between 207 and 253 volts for a motor nameplated 230 volts. If no voltage is recorded, check fuses, circuit breakers, timers, wiring, etc. for open connection or broken wires.
PAGE 7
32 Pump Motors Amperage Check • Make sure power is off. • Set ammeter scale based on Max. Load amps. • Position one line lead (L1 or L2) so that the jaws of ammeter can encircle one power lead. (It will usually be necessary to install a test loop to have room for the meter jaws.) • Make sure switch and governor are free of obstructions (if applicable). • Reconnect power • Start the motor Caution: All wires are live (hot) so use extensive care. • Take a reading.
PAGE 8
33 Pump Motors Perform the following checks to confirm that each component is functioning properly. Ground Check • Turn the power off. • Set ohmmeter to R x 1K. • Attach one probe to ground screw on the end frame and touch the other probe to all terminals on the terminal board, switch, capacitor and protector. A reading of less than 10K could indicate a ground. New motors typically read over one megohm.
PAGE 9
34 Pump Motors • Make sure there are no obstructions preventing the proper operation of the rotating governor. Check wiring and make sure none of the leads are in the area of the governor where they can be cut or interfere with the governor. Check governor for proper operation and make sure flipper moves freely. • Check switch contacts for severely burned or pitted contacts, sticking etc. Some blackening or pitting is normal after the motor has been used. Replace switch if there is any doubt.
PAGE 10
35 Pump Motors Disconnect one of the red leads to the switch. Discharge capacitor by shorting across the terminals with the blade of an insulated handled screwdriver. Take the following ohm readings. L2 & A A & YELLOW Resistance between L2 and A must be the same as resistance between A and Yellow. YELLOW TO RED L2 TO RED Yellow to Red (winding side of switch) must be same as L2 to same Red terminal. A.O.
PAGE 11
36 Pump Motors Protector (Thermal Overload) Check • Set ohmmeter to R x 1. • Resistance between terminals: 1 & 2 should be approximately 0 (Disc.) 2 & 3 should be approximately 0 (Heater) • Replace if either value exceeds 1 ohm. TIP: Motor cycling on overload indicates some other problem not just a defective overload. Capacitor Check (Start or Run) • Set ohmmeter at Rx 1K. • Slip a heavy piece of paper between points on the switch.