Control/Dimming Is this possible: Lamp failure breaks a dimmer?
- Thread starterslimrocktwo
- Start date
Yes its possible your lamp caused the breaker to fail. Think of that broken filament while for that micro second in breaking flopping about and causing an arc between supply and return as if an arc lamp - now given an arc gap with high resistance for that moment but also for that moment limited to zero resistance to current flow. Or the other way around.
Broken filaments can arc in that last instance while it breaks and trip a breaker.
Broken filaments can arc in that last instance while it breaks and trip a breaker.
I have had cases of lamp failure killing the Solid State Relay (SSR) in dimmer modules. Over the years, I have had it in Strand CD 80, EDI series 7, Teatronics and an LMI rack. The one thing that is common in all of these situations, is that the SSRs were crydon. I mention that just because it happened, but The fact that Crydon makes most all of the SSRs that are used in dimmer racks, the odds are that they would be the ones to fail. The real problem as I see it is that some times the lamp arcing across when it burns out, is so fast that the breaker doesn't always react quick enough. In every case of SSR failure that I can remember, the breaker also tripped. Read into it what you like, I'm not presenting a conclusion, just stating some experiences.
By the way the dual 40 amp Crydon SSR, that is used in so many dimmer modules, has many different prices depending on the purchase location. I have found them for $100 from the dimmer manufactures, and for around $55 at some electronic suppliers and the lowest was $35 at digikey. That was quite some time ago, so it may be priced higher by now.
By the way the dual 40 amp Crydon SSR, that is used in so many dimmer modules, has many different prices depending on the purchase location. I have found them for $100 from the dimmer manufactures, and for around $55 at some electronic suppliers and the lowest was $35 at digikey. That was quite some time ago, so it may be priced higher by now.
see my explanation on page two of what can cause a TRIAC failure when a lamp fails. The problem is that a breaker you will find installedn a dimmer cannot protect against this type of problem because a standard breaker works on a thermal effect. This requires many cycles of the voltage waveform for it to react whereas the TRIAC or SSR as you refer to it has failed within one half cycle. Other types of breakers are available that can provide protection within a half cycle but they will not fit into your dimmer rack and the cost of such a dimmer pack would be prohibitive.
Unfortunately this type of issue is one of the factors you consider during the design of the dimmer or relay pack if you have not taken the appropriate steps in the design to limit the rate of change of voltage or current then you will experience TRIAC failures - not necessarily every time but it does happen. Note also that even when this is taken into account that a soft component failure of a capacitor or even high levels of dirt on inductor can change the performance of these components enough to give problems. this is why when snubber circuits and output filter circuits are included in a dimmer and TRIAC failures are being experienced you also need to check out these components
Unfortunately this type of issue is one of the factors you consider during the design of the dimmer or relay pack if you have not taken the appropriate steps in the design to limit the rate of change of voltage or current then you will experience TRIAC failures - not necessarily every time but it does happen. Note also that even when this is taken into account that a soft component failure of a capacitor or even high levels of dirt on inductor can change the performance of these components enough to give problems. this is why when snubber circuits and output filter circuits are included in a dimmer and TRIAC failures are being experienced you also need to check out these components
gordonmcleod
Active Member
Fully magnetic circuit breakers will not protect a triac and often not even a SSR block
Gordos was also a major player in providing SCR modules to several dimmer manufacturers as well
Often one needs to be carefull in that many SSR modules have a zero crossing detector built into them since they are as their name implies a Solid State Relay (SSR) and as such is designed to switch only at the zero crossing point to prevent switching noise from the rise time
Strand was I believe the first to use them and the Cyrdon one they used was originally special ordered without the zero crossing in it
Gordos was also a major player in providing SCR modules to several dimmer manufacturers as well
Often one needs to be carefull in that many SSR modules have a zero crossing detector built into them since they are as their name implies a Solid State Relay (SSR) and as such is designed to switch only at the zero crossing point to prevent switching noise from the rise time
Strand was I believe the first to use them and the Cyrdon one they used was originally special ordered without the zero crossing in it
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