Garage door opener not working.

[GG]

I installed 2 electronic ballasts in a F48 T12 fluorescent light fixture that is mounted on a garage ceiling. Now the HO is calling me back saying that ever since I installed the 2 ballasts that his garage door opener does not work like it use to. He stated that its "not a strong as it use to be. and the hand held opener works intermitently." He is an engineer and telling me he thinks the problem is electromagnetic leakage from the ballasts that are causing some type of interference. He had a garage door repair co. come out and when they turned the breaker to the lights off everything with his door opener all of a sudden worked propelly. I have to go to his house Monday. Any ideas on fixing the problem. I dont think putting 2 new ballasts is going to do anything.

 

[tshea]

I don't believe there is any relationship between the opener and the lights. You have fallen into the trap known as "the last guy on the job." Whatever is wrong is your fault! Toliet leaks, creaking floor, weak garage door opener. You were the last guy there, it's all your fault.

Seriously, is there any wiring common between the opener and the lights? That is where I would look. Can you "turn off" the lights and operate the opener and vise versa? That will give you a starting point to check.

 

[Johnmcca]

What about the possibility there being a common neutral between the light circuit and the opener, with the harmonics from the ballasts causing the interference. Not "electromagnetic leakage'. :idea:

 

[infinity]

What about the possibility there being a common neutral between the light circuit and the opener, with the harmonics from the ballasts causing the interference. Not "electromagnetic leakage'. :idea:

There would be no harmonics on a single phase residental system in a dwelling.

 

[normbac]

Had similiar problem, moved the breaker to opposite buss, problem solved. never figured out why

 

[GG]

Thanks for the replys. Im going to ask the HO if he replaced the batteries in the wireless opener, and if the wall mounted opener works when the light switch is off. I do have a feeling Im caught in the "last guy there" trap.

 

[JohnE]

I can't tell you how many times I've heard "such and such worked fine until you worked here". It's always been a case of someone just noticing something not working after we've left. Like a blown lightbulb on the back door when we were at a house to fish in a CATV jack. Probably was out for 2 years.

 

[busman]

There would be no harmonics on a single phase residental system in a dwelling.

Could you please explain? My Power Quality meter must be broken then.

Thanks,

Mark

 

[ron]

You will find harmonics on a single phase (120V) circuit, but you will not find that they add on the neutral (240/120V single phase), like on a three phase system.

 

[busman]

I would disagree. The even harmonics will add in the neutral just like the triplen harmonics add on a 3-phase system. Fortunately, even harmonics usually contribute less to the overall harmonic content (depending on the load type) than odd harmonics.

Mark

 

[don_resqcapt19]

Busman,

The even harmonics will add in the neutral just like the triplen harmonics add on a 3-phase system.

How? They are oposite from each other and cancel in a single phase system.
Don

 

[busman]

Don,

It's hard to see if you think of the two legs of single phase as being "opposite" phases. They are really two waves of the same frequency delayed by a half cycle in time. Now for 3 phase, the third harmonic repeats every 1/3 of a cycle so it begins again at the same time a wave from one of the other phases starts - hence, they add. For 2 phase (single phase can be thought of as 2 phase for this explanation), the second harmonic begins again after 1/2 cycle of the fundamental. This is the time that the "second" phase is starting. The second phase generates the same harmonic as the first and they add. There is nothing mathematically special about 3 phase, its just that most non-linear devices (like SCR's) primarily generate odd harmonics.

I know this is not the best explanation. If I could figure out how to post an image, it would help.

Mark[/img]

 

[eric stromberg]

There is nothing special about three phase math?

au contraire mon ami (sp?)

I think three phase math is very special.

(Now if only i could figure out how to use those emoticons. I'm great with math, but simple things like dragging and dropping...)

Eric

 

[busman]

Eric,

My French is pretty bad, but now you're just scaring me.

Mark :shock:

 

[ron]

Mark,
I think the trick is drawing out the waveform of the two 120V sources (180 degrees apart), then drawing the third harmonic of those. Ad the two third harmonics together, as they would coexist on the neutral and see that they don't add (not in phase, like a three phase waveform).
I am not that good wit graphing programs to do this, but I've seen it done.

 

[eric stromberg]

Mark,
Yes; French is pretty scary, isn't it?
They have all those consonants and seem to only use about half of them.

:?

Eric

 

[rick hart]

The electronic ballasts work at a much higher frequency than the old mag coil ballasts. I'm thinking that the receiver from the opener is being scrambled by the RFI that the HF ballast put out.

If you do replace the ballasts, use mag coil and let them listen to the hum.

 

[busman]

Ron,

I don't recall ever saying that the 3rd harmonics of a single phase system would add in the neutral. My point was that single phase systems do have harmonics and that the even harmonics of single phase systems add in the neutral just as the triplen harmonics add in a three phase system. Additionally, most nonlinear sources tend to produce odd harmonics, hence - even harmonics are not much of a problem.

Mark

 

[tshea]

Yowza--see how fast this thread changed from a garage door opener to harmonics. You guys are great :twisted:

 

[Ani]

Hi guys,

I normally just browse these forums since I'm a DIY homeowner that knows a just tad bit or more about electrical; I "do" only wire under city permits though :wink: . I ran across this thread searching for answers to other questions I have and thought I'd respond.

I worked for a garage door manufacturing company that sold electronic operators in its' retail division for 7 years. Phantom operation or intermittant signals of radio controlled garage door operators were a major complaint and probably one of the most common service calls for electronic garage door operators. The following quote is spot on....

The electronic ballasts work at a much higher frequency than the old mag coil ballasts. I'm thinking that the receiver from the opener is being scrambled by the RFI that the HF ballast put out.

The addition of a new microwave oven by the home owner, an airplane flying over the home, and a multitude of other things were capable of causing people's doors to open without being commanded to do so by the supplied activation devices accompanying the garage door opener. The problems were resolved, not by reinstalling or removing an added unit, but rather a change of frequency in the garage door opener and its' controllers. If the unit is digital, the change of frequency is fairly simple by the repositioning of buttons located inside the transmitter and its' receiver.