pscandrett Posted February 7, 2019 Share Posted February 7, 2019 A Patt45 is ideal - very little light output!Heh. A friend has had some success with a plug-in air freshener as a dummy load in the past. Link to comment Share on other sites More sharing options...
J Pearce Posted February 8, 2019 Share Posted February 8, 2019 A 50W GU10 birdie can provide a usefully compact and vaguely rugged load lamp. Wants to be a mains GU10 though, not an MR16 with transformer. Usually one is enough to keep the dimmer happy. Link to comment Share on other sites More sharing options...
sunray Posted February 8, 2019 Share Posted February 8, 2019 A friend has had some success with a plug-in air freshener as a dummy load in the past. That's a bit of a surprise, I have never handled a plug in air freshener (personally I abhor the stench and horrible chemicals being deposited in my lungs). I had always assumed these things are very low power as they don't get warm, something in the order of a watt or two maximum. Link to comment Share on other sites More sharing options...
bigclive Posted February 8, 2019 Share Posted February 8, 2019 A friend has had some success with a plug-in air freshener as a dummy load in the past. That's a bit of a surprise, I have never handled a plug in air freshener (personally I abhor the stench and horrible chemicals being deposited in my lungs). I had always assumed these things are very low power as they don't get warm, something in the order of a watt or two maximum. Typically about 2W. It's possiblke that the load may have been electronic or on the edge of operation if such a low resistance helped the dimmer latch. Link to comment Share on other sites More sharing options...
Jivemaster Posted February 8, 2019 Share Posted February 8, 2019 AFAIK no dimmer manufacturer actually specifies the minimum current for reliable operation. Maybe it depends on the nature of load applied maybe it depends on the rated current of the dimmer. If it needs 100mA for a dimmer to run well then a 80ma load needs little help. Would a 5A dimmer need the same minimum load as a 20 or 50A dimmer channel? My first try, if a load was too small for the dimmer to run well would be a 60w tungsten filament lamp. My understanding of the bigger loads was that they were used to hide the inductive component of a very small load such as a mirror ball rotator which is about 2 - 3w rating but a frequent killer of dimmers Link to comment Share on other sites More sharing options...
alistermorton Posted February 8, 2019 Share Posted February 8, 2019 Our SLD rack is happy with a 40W lamp. The Act6 we sometimes haul out wants 100W. I tried it with 50W GU10 lamps on each channel and it wasn't happy at the very bottom end. Not entirely sure why. Link to comment Share on other sites More sharing options...
DrV Posted February 8, 2019 Share Posted February 8, 2019 Our SLD rack is happy with a 40W lamp. The Act6 we sometimes haul out wants 100W. I tried it with 50W GU10 lamps on each channel and it wasn't happy at the very bottom end. Not entirely sure why.It's a combination of two factors - the holding current of the thyristors or triacs, and the method used to trigger them. Higher current devices typically have a higher holding current so to answer Jivemaster's question above, Yes a big dimmer may well require a higher dummy load. At low levels the triac is being triggered at a point in the cycle where the load current is only ever going to be low and might not be sufficient to hold the device on so you end up with Alister's point that they work ok at higher levels but not really low levels. The same issue could theoretically occur at very high levels too as again the trigger is ocurring at a low current part of the cycle, however the triggerring method then comes into play - if you are only using a short trigger pulse then indeed the device might not switch on at all at high levels. Most theatrical dimmers don't suffer from this because they either provide a stream of trigger pulses or a continuous D.C. trigger.Inductive loads introduce a whole new set of problems because the current and voltage are not in phase with each other!But I've wittered on enough...Dave Link to comment Share on other sites More sharing options...
Edward- Z88 Posted February 9, 2019 Share Posted February 9, 2019 AFAIK no dimmer manufacturer actually specifies the minimum current for reliable operation. Maybe it depends on the nature of load applied maybe it depends on the rated current of the dimmer. If it needs 100mA for a dimmer to run well then a 80ma load needs little help. Would a 5A dimmer need the same minimum load as a 20 or 50A dimmer channel? Just for reference in case it may be useful for others, Betapack 3 dimmers can allow for a minimum load per channel of 0.1A, and Alphapack 3s have a minimum load per channel of 0.2A. Edward Link to comment Share on other sites More sharing options...
bigclive Posted February 9, 2019 Share Posted February 9, 2019 Just out of interest. Are these LED fairy lights? And is the problem actually latching issues or snubber leakage causing low end residual glow. And if they are simple non flashing 240V fairy lights which type are they? Link to comment Share on other sites More sharing options...
adam2 Posted February 9, 2019 Share Posted February 9, 2019 Most mains voltage, series wired incandescent fairy lights use between 90ma and 150ma per string. Link to comment Share on other sites More sharing options...
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