Microwave question

Susan1

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Not a microwave question! I looked you up in this thread because you seem to understand electrical stuff and you would see that I replied to you. Something else I can't find anywhere to ask..................
I have two lamps with three way bulbs in them on the same wall, but different outlets maybe 10 feet apart. Both of them have only been able to use the second brightness for years, even after I have changed the light bulbs. (You know I can't say this stuff technically.) I use the one to read practically every day and I am used to going click, click because the first click doesn't make any light come on. So Sunday, I went click..........and there was light and then click and click and I had three brightnesses. I tried the other lamp and it too had three brightnesses. I had unplugged that one a couple days before when it was cooler out and I was vacuuming behind the loveseat (which I do at least once a year). But the one I use for reading didn't work on the first setting right after that. I know this is confusing. "You'd have to be there."!
It's a good thing that I have three brightnesses, but why, out of nowhere? Is there too much power going through that wall now or something? They'll probably both blow out the next time I use one.
 

Susan1

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9,437
Did you switch to three-way lightbulbs?
They have always been three-way light bulbs - 50-100-150 watts. I mean always like these two lamps have been in this house for probably 30+ years. The 50 part and 150 parts have not worked for the last few years, even after I changed a bulb when it blew out. Only the 100, which is really too hot to read by during the day. (It's been too hot to leave the curtain open because there is a big picture window where the sun comes in. And of course the cold hits the glass in the winter.........)

Now all settings work - in both lamps! Why??? I keep testing them a couple times a day. I'm going to wear them out. It was cloudy today and I read for a while with the 50 watt setting.
 

rvi5

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3-way lamps require 3-way bulbs, a 3-way lamp socket, and a 3-way lamp switch. The bulb contains two filaments providing low 50W and medium 100W light. The brightest light is obtained by both filaments lighting together (50W + 100W = 150W). The switch routes the electricity through the appropriate contacts in the 3-way socket, into the bulb. If you look at the base of a 3-way bulb, it has two hot contact points. A small circular metal dot in the bottom middle (medium 100W light), and a metal ring surrounding that dot (low 50W light). The outer threaded bulb casing is the common neutral return path for the electricity. See the link below for a detailed explanation...

https://www.wikiwand.com/en/3-way_lamp

If you do not get light at a specific switch setting, it could mean one filament in the bulb is burnt-out. It could also mean the bulb is loose in the socket, not making solid contact with both the dot and ring at the bottom of the bulb. Other possibilities include one somewhat flattened spring contact tab in the lamp socket, or perhaps a loose contact connection in a defective switch. Since you had changed bulbs, it would not be the burned-out filament scenario.

I assume you get no light on the first switch click (ie. no electricity flowing through both the ring or dot contact at the bottom of the bulb). You get 100W light on the second switch click (electricity only flowing through the dot contact). Did the light turn off on the third switch click, or did it stay on at the previous 100W medium brightness? The fourth click should have turned the lamp off.

What I find confusing, is why both lamps would start fully working simultaneously. The electrical outlets should not have any effect on the function of the lamp switches.
 
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Susan1

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9,437
I assume you get no light on the first switch click (ie. no electricity flowing through both the ring or dot contact at the bottom of the bulb). You get 100W light on the second switch click (electricity only flowing through the dot contact). Did the light turn off on the third switch click, or did it stay on at the previous 100W medium brightness? The fourth click should have turned the lamp off.
third click stayed the same as the second one.
What I find confusing, is why both lamps would start fully working simultaneously.
Yeppers!
du-du-du-du (Twilight Zone music) :)
 

rvi5

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third click stayed the same as the second one.
That is what I suspected. Electricity should have flowed to both the dot and ring contacts at the bottom of the bulb on the third click. In your case, it only flowed to the dot. Hence the lamp behaved the same as the second click. In the 3-way socket diagram from the link I posted, contact #2 either did not touch the bulb’s bottom ring, or one of the switch’s internal contacts temporarily failed.
 
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