Solid state relay and fluorescent lamps

"Jean-Marc Delaplace" schreef in bericht news:fPZMg.142$ snipped-for-privacy@nntpserver.swip.net...

Hmm... Celduc produces quite some types. What type did you use?

petrus bitbyter

We used a lot of SSRs in check sorters hence I brought a lot home to play with.. We found they did fail a lot when used at much more than

40 or 50% of the rating. Another thing I have found is you need a fairly clean DC voltage (ripple never sagging below the "on" level") or they start to look like a dimmer. I am using them all over my house but these are the big "block" type 2a-45a, made by Opto22 or Crydom.

the question is, is the relay actually pulling in ? if so then the contacts are burnt.. other wise you have some other issue. if its contacts, you could try a solid state switch. they come in various sizes and control voltages.

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Good one Jamie, explain how one cleans up the contacts in an SSR :-)

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Simple. A light saber powered by a flux capacitor, or in a pinch you might get by with a "Mr Fusion" if you can't find a flux capacitor.

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The important component here isn't the lamps, it's the ballast. If the ballast has a filter capacitor/electronic circuit, it might have a large inrush current (and triac SSRs have a dI/dt limit that can be exceeded).

The other type of ballast is an inductor, heavier than the electronic type; these can be driven crazy with a little bit of DC (like if your SSR turns on on positive half-cycles more often than on negative ones). If they get DC, they can saturate and the fluorescent will flash brightly when the current spikes.

The solid state ballast will work best with a zero-voltage-switching SSR, while the inductor ballast would prefer an inductive-load-rated unit. It would be prudent to put a varistor surge suppressor in the circuit, too.

Marc,

SSR failure is common. In my experience and opinion, ANY device from the thyristor family is an unreliable piece of crap. That's personal experience from replacing bad or intermittent SSRs for studio lighting. Guess why UJTs are no longer used? Ever even heard of an SCS? Lack of reliability killed off the SCS (GE Silicon Controlled Switch) back in the early sixties.

I replaced the power relay in one of my TVs with an appropriate Crydom SSR. It lasted 7 years until it became intermittent when the TV warmed up.

Almost half of the light dimmers (Triac devices) that I installed in my house have failed over 20 years. Thyristors just do not have the longevity.

I certainly would worry if these things were used in medical or aerospace applications.

Bob

I just noticed.....You have added power correcting capacitors in your residential wiring? Why? Where I live in Canada, power factor correction is not required for residences. The home-use power meters mounted to the exterior of the house are smart enough so that you are only billed for KW hours used, not kilo-volt-amp-hours. Out of phase current is ignored. This is not so with factories and some businesses. Factories use large amounts of reactive power because they run very large and numerous induction motors, so the power company bills them for reactive power (KVAH) to encourage them to manage the power factor and keep the total Hydro plant current as low as possible. This keeps the grid from overloading from excessive amperage.

And I'm ALSO surprised that you are using power factor correction for such a low power circuit.

Regards, Bob

It's not a question of billing. Millions of uncorrected ballasts leads to wasted power.

In message , dated Wed, 13 Sep 2006, Bob Scott writes

Old fluorescent fittings had them built-in. In UK anyway. I don't know when they ceased to be fitted.

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