Ceiling Fans

© 2006 Dr. Ray Franco, PhD., PE    r.a.franco@ieee.org


Ceiling fan fires are rare. I have never encountered one. The majority of ceiling fans sold in the USA are imported from China, and they are approved by Underwriters Laboratories (UL). UL507 is the general UL Standard for fans. UL507 references UL2111, which is the UL Standard for thermally protected motors. The two major ways of thermally protecting a motor are: (1) by using a detective device in series with the power that opens when an over temperature is sense, and (2) impedance protection, where the impedance of the motor windings limit the amount of heat generated, even in abnormal situations such as a locked rotor condition. All of the ceiling fans I have disassembled were impedance protected. Impedance protected motors are subject to a test where the rotor is locked for 15 days, and the temperature of the motor is monitored for the first three days.


Case History: Exemplar 42" Ceiling Fan Purchased at Home Depot in 2006 for $19.99.

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Hampton Bay / SMC Ceiling Fan Box

Ceiling Fan Box - Home Depot, Homer TLC Inc. / Hampton Bay

SMC Fan Tag

Manufacturer's Tag - E136322 Traced on UL Website to Shell Electric MFG Co. (SMC) in Hong Kong.

Fan Specifications

Fan Specifications.

SMC Fan

Ceiling Fan without Canopy, Mounting Brackets, and Blades.

Locked Rotor - Max Temp

Locked Rotor for 4 Hours -
Locked Rotor Current, 0.264 Amps, and Maximum Temperature 272° F.

Locked Rotor Temps

Locked Rotor Temperatures after 4 Hours:
132° F at Mounting Bracket and 224° F at Top of Motor Frame (Inside).

Stator

The Stator (16 poles) is on the Inside, and the Rotor (Induction - Squirrel Cage) is on the Outside of the Motor.

Stator & Rotor

Disassembled Motor Depicting Separated Stator and Rotor.

North Pole

Stator Winding Powered with 9 Volt Transistor Battery.
Location of One of the North Poles.

SOuth Pole

Stator Winding Powered with 9 Volt Transistor Battery.
Location of One of the South Poles.

Fan Junction Box

Fan Junction Box Inside the Light Housing.

Junction Box Components

Components in the Fan Junction Box .

Multi-Value Capacitor

Multi-Value Capacitor Used to Control Speed and Create a Rotating Magnetic Field.

SMC Fan Schematic

Schematic of SMC Ceiling Fan Model 270614.
Run Winding Resistance: 189 Ohms; Aux. Wind. Resistance: 157 Ohms.


Case History: Exemplar 52" Ceiling Fan from New Manufactured Home. Distributor: Global Electric; P.O. Box 590902, Arlington, Texas.

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Global Electric Fan

52 Inch Ceiling Fan Components.

HOng Sui Tag

Manufacturers Tag - E256060 Traced on UL Website to Hong Sui Industries in Hong Kong.

Motor North Pole

Stator Winding Powered with 9 Volt Transistor Battery.
Location of One of the North Poles.

Motor South Pole

Stator Winding Powered with 9 Volt Transistor Battery.
Location of One of the South Poles.

Junction Box Reserve Direction

Fan Junction Box Depicting Reverse Direction Switch.

Start & Speed Capacitor

Multi-Value Capacitor Used to Control Speed and Create a Rotating Magnetic Field.

Ceiling Fan Schematic

Schematic of Hong Sui Industries Ceiling Fan Model BM52-3LK.
Run Winding Resistance: 75 Ohms; Aux. Wind. Resistance: 72 Ohms.

Bearing Puller

To Disassembly a Ceiling Fan Motor, You Need a Jaw or Bearing Puller.


 

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