Relay failures in lighting controller

No, but I do mostly gas. I've seen plenty of crap welds with a short piece of rod sticking out from the weld. My wire welder hasn't been used in more than a decade, since most of the time I have to work where there is no power to run the electric welders.

Sigh. Sigh. Sigh.

How do you start the arc? You touch it to the grounded workpiece just enough to start the arc. Then there is a continuous 'connection' via the plasma generated by the initial arc.

Any type of welding or soldering overhead leaves nasty results. Vertical is easier, but takes a steady hand and practice, practice, practice. I did most of my SMD work at an incline or vertical to take advantage of gravity. It let the small ball of molten solder to collect the slag as you went down a row of pins. It looked a hell of a lot better than doing it horizontal.

That's getting close. Something like this shouldn't have a problem:

prevent

All

There are multiple processes going on. Contacts that are badly pitted are easier to weld on closure due to irregular contact area.

?-)

The answer is yes.

The relay contcts were welding in the first 10 or so operations with AgNi contacts.

So far AgSnO contacts have survived 10,000 operations on the same load.

ote: > " snipped-for-privacy@fonz.dk" wrote: > > > On Feb 3, 4:00 am, Jamie > > wrote: > > > Jasen Betts wrote: > > > > On 2013-02-01, Robert Macy wrote: > > >

er in front of them to prevent > > > >>the conducted emanations. What you h ave there is a capacitor across > > > >>the AC mains followed by some husky inductance. That makes the load > > > >>look incredibly inductive, not cap acitive - with main impact as you > > > >>turn it off. To envision, simply unplug your PC very slowly from the > > > >>AC outlet. Even with it turned off, you'll draw an impressive arc. All > > > >>due to the stored energy in the EMI filter. I suspect it is THAT > > > >>energy that is welding the co ntacts together. > > > > > contacts can't weld closed while they are open.

derived surge current through the bouncing > > > > contacts heats them up t o melting and the weld closed. > > > >   They most certainly can weld tog ether while they are in > > > the process of opening with induction loads. Which is why > > > special designs are out there just for handling inductio n > > > loads. > > > I have hard time seeing how it can happen when opening , arc > > start when they are already moving apart so unless you close them > > instantly after being melted by the opening arc I don't see how > > th ey could weld > > > at closing it is more like spot welding, melt and press together > > > >    If you don't use the correct contact design for th ese types > > > of loads, the relay will not last long. > > > > Jamie > > > sure arcing at opening will eat the contacts, but that is different > > >

-Lasse > >    You've never done any arc welding, have you? I have done plenty of welding, stick and tig have you ever got the rod stuck while pull ing it off? -Lasse

Hello there. I think modern HF flourescent light fittings probably use high voltage mosfets (500-900volts)electronic balasts probably presenting an o perating reactive load that is similar to switched mode PSUs (Transmitters, telecoms,server bank PCs) which calls for a substantual derating of your re lay in question. 16A resistive(heating element load) but only 2A reactive l oad is typical of external integral halogen lamp PIR controller or 5-6A max reactive for seperate PIR module. Probably call for the 15A (600-800mW) or 25A (30/20A DPDT Finder) (1-2W) for conventional mechanical relay from Map lin (or rapidonline.com). There are also 25A electronic relay modules (farn ell.com) that use triac switching (might NOT be suitable).

wrote: > > > Jasen Betts wrote: > > > > On 2013-02-01, Robert Macy wrote: > > >

front of them to prevent > > > >>the conducted emanations. What you have there is a capacitor across > > > >>the AC mains followed by some husky inductance. That makes the load > > > >>look incredibly inductive, not capacitive - with main impact as you > > > >>turn it off. To envision, simply unplug your PC very slowly from the > > > >>AC outlet. Even with it turned off, you'll draw an impressive arc. All > > > >>due to the stored energy in the EMI filter. I suspect it is THAT > > > >>energy that is welding the contacts together. > > > >

through the bouncing > > > > contacts heats them up to melting and the weld closed. > > > > They most certainly can weld together while they are in > > >

the process of opening with induction loads. Which is why > > > special designs are out there just for handling induction > > > loads. > > > I have hard time seeing how it can happen when opening, arc > > start when they are already moving apart so unless you close them > > instantly after being melted by the opening arc I don't see how > > they could weld > > > at closing it is more like spot welding, melt and press together > > > > If you don't use the correct contact design for these types > > > of loads, the relay will not last long. > >

different > > > -Lasse > > You've never done any arc welding, have you? I have done plenty of welding, stick and tig have you ever got

voltage mosfets (500-900volts)electronic balasts probably presenting an operating reactive load that is similar to switched mode PSUs (Transmitters,telecoms,server bank PCs) which calls for a substantual derating of your relay in question. 16A resistive(heating element load) but only 2A reactive load is typical of external integral halogen lamp PIR controller or

5-6A max reactive for seperate PIR module. Probably call for the 15A (600-800mW) or 25A (30/20A DPDT Finder) (1-2W) for conventional mechanical relay from Maplin (or rapidonline.com). There are also 25A electronic relay modules (farnell.com) that use triac switching (might NOT be suitable).

What the hell are you posting with? It completely destroys the messages in your reply.

It says User Agent G2/1.0 which appears to be Google Groups. They probably made another "improvement".

Paul

wrote: > " snipped-for-privacy@fonz.dk" wrote: > > > On Feb 3, 4:00 am, Jamie > > wrote: > > > Jasen Betts wrote: > > > > On 2013-02-01, Robert Macy wrote: > > > > >>First place I'd look... > > > >>Electronic ballasts require an EMI filter in front of them to prevent > > > >>the conducted emanations. What you have there is a capacitor across > > > >>the AC mains followed by some husky inductance. That makes the load > > > >>look incredibly inductive, not capacitive - with main impact as you > > >

All > > > >>due to the stored energy in the EMI filter. I suspect it is THAT > > > >>energy that is welding the contacts together. > > > > > contacts can't weld closed while they are open. > > > > therfore the

current through the bouncing > > > > contacts heats them up to melting and the weld closed. > > > > They most certainly can weld together while they are in > > > the process of opening with induction loads. Which is why > > > special designs are out there just for handling induction > > > loads. > > > I have hard time seeing how it can happen when opening, arc > > start when they are already moving apart so unless you close them > > instantly after being melted by the opening arc I don't see how > > they could weld > > > at closing it is more like spot welding, melt and press together > > > > If you don't use the correct contact design for these types > > > of loads, the relay will not last long. > > > > Jamie > > > sure arcing at opening will eat the contacts, but that is different > > > -Lasse > > You've never done any arc welding, have you? I have done plenty of welding, stick and tig have you ever got

high voltage mosfets (500-900volts)electronic balasts probably presenting an operating reactive load that is similar to switched mode PSUs (Transmitters,telecoms,server bank PCs) which calls for a substantual derating of your relay in question. 16A resistive(heating element load) but only 2A reactive load is typical of external integral halogen lamp PIR controller or 5-6A max reactive for seperate PIR module. Probably call for the 15A (600-800mW) or 25A (30/20A DPDT Finder) (1-2W) for conventional mechanical relay from Maplin (or rapidonline.com). There are also 25A electronic relay modules (farnell.com) that use triac switching (might NOT be suitable).

It looks like varient412 is using Netscape 4.8 with very messed up settings. He seems to be doing an Earthlike - giganews cha-cha as well.

?-)

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