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gemelli2
pop..out goes the light

Hi,
I have a ceiling fan (that has a light) in my office that has been working perfectly for the past 2 years or so since i put it in. One thing to note: this is a 1885 house and the fan is on the top floor. the wiring is not new but works just fine.

Yesterday, i went into the room and turned on the light switch which controls the fan (i have the fan light on - so the switch automatically turns the light on without having to pull the chain on the fan)....when i turned the switch on i heard a pop and the light didn't go on. I didn't notice if the lights went on for a split second and then went off - or if they just never went on.

i thought - ok - the light bulbs need to be changed - but when i changed them and switched the light on, nothing happened! Here's the weird thing: when i pull the chain for the fan, that works fine!

So why would the lights suddenly stop working and the fan be fully functional when coming from the same wire? Any thoughts???

thanks!

dj1
Re: pop..out goes the light

Take the fan assembly apart - and find out.

The motor and the light share the same main wall switch, but inside they have 2 leads, usually black and blue - one for the motor and one for the light.

Re: pop..out goes the light
gemelli2 wrote:

Hi,
I have a ceiling fan (that has a light) in my office that has been working perfectly for the past 2 years or so since i put it in. One thing to note: this is a 1885 house and the fan is on the top floor. the wiring is not new but works just fine.

Yesterday, i went into the room and turned on the light switch which controls the fan (i have the fan light on - so the switch automatically turns the light on without having to pull the chain on the fan)....when i turned the switch on i heard a pop and the light didn't go on. I didn't notice if the lights went on for a split second and then went off - or if they just never went on.

i thought - ok - the light bulbs need to be changed - but when i changed them and switched the light on, nothing happened! Here's the weird thing: when i pull the chain for the fan, that works fine!

So why would the lights suddenly stop working and the fan be fully functional when coming from the same wire? Any thoughts???

thanks!

The fan has a capacitor and motor windings both of which store energy and will created a surge in line voltage when turned on or off.

The incandesent lamps prior to being turned on have a very low resistance and will draw at least 10 times the current they normally draw lighted. Again a huge surge.

Power distribution in the US is 60 Hz alternating current. This means when you flipped the wall switch it have been the instant in time where the voltage was at it's maximum. Again a huge surge.

Any one, or combination, of these factors could be the reason the lights failed.

gemelli2
Re: pop..out goes the light
dj1 wrote:

Take the fan assembly apart - and find out.

The motor and the light share the same main wall switch, but inside they have 2 leads, usually black and blue - one for the motor and one for the light.

thanks for your response! I will open it up and look inside - but am i looking for in particular? A loose wire? Something that looks burnt? Sorry...i am a novice!

And if i did turn it on at the precise moment of a surge, what does that mean? That the light unit is toast?!:confused:

gemelli2
Re: pop..out goes the light
The Semi-Retired Electric wrote:

The fan has a capacitor and motor windings both of which store energy and will created a surge in line voltage when turned on or off.

The incandesent lamps prior to being turned on have a very low resistance and will draw at least 10 times the current they normally draw lighted. Again a huge surge.

Power distribution in the US is 60 Hz alternating current. This means when you flipped the wall switch it have been the instant in time where the voltage was at it's maximum. Again a huge surge.

Any one, or combination, of these factors could be the reason the lights failed.

Hi
The Semi-Retired Electric - thanks for your reply!

so ...i could have turned it on at a bad time;-) Are you saying that because of this, the lights are toast and i will have to replace the unit? or ...?

keith3267
Re: pop..out goes the light

You probably burned the wire off at the lamp socket, that tends to be the weak point. They usually do fail right at turn on because that is when the current is highest, but it was ready to go. It had been getting weaker over time and finally, it was just one turn on away from burning apart. and then it happened, not your fault.

I recommend that you remove the fuse for this circuit before you work on it. Considering the age of your house, I would be concerned that the wall switch might be cut into the return wore instead of the hot wire. That would be a code violation today, but your wiring could predate the codes. Electricians have been electrocuted because of this.

Re: pop..out goes the light
gemelli2 wrote:

Hi
The Semi-Retired Electric - thanks for your reply!

so ...i could have turned it on at a bad time;-) Are you saying that because of this, the lights are toast and i will have to replace the unit? or ...?

Well there was no way for you to predict the correct instant to flip the switch. It's like spinning a wheel of chance.

Have you ever gone into a dark room and flipped a light switch and saw a flash in the switch? Then, flipped the switch ten more times and no flash?

It's perfectly normal but depending on where the voltage peak in your house is at that moment an expensive surge could result.

Expensive equipment are designed with "zero cross-over" circuitry which prevents this problem by only permitting a circuit to be energized when the voltage is zero, which occurs 120 times per second.

Fortunately, your problem is probably just a switch or loose connection.

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