edmonston Posted March 19, 2013 Share Posted March 19, 2013 Would a bulb from a Fresnel work in a Pebble Convex? Link to comment Share on other sites More sharing options...
Jivemaster Posted March 19, 2013 Share Posted March 19, 2013 Bulbs grow, lamps glow. Any lamp will fit IF it's the right type -that means capsule shape, and filament size shape and rating, and base type and position. Oh! And burning angle as well. Link to comment Share on other sites More sharing options...
edmonston Posted March 19, 2013 Author Share Posted March 19, 2013 Bulbs grow, lamps glow. Any lamp will fit IF it's the right type -that means capsule shape, and filament size shape and rating, and base type and position. Oh! And burning angle as well. The bulb fits, but my schools New Technologies manager had a rant at me about wattages 'n' stuff Link to comment Share on other sites More sharing options...
paulears Posted March 19, 2013 Share Posted March 19, 2013 Was the new lamp a higher Wattage than the old one, then? Just because the base fits doesn't mean it's ok for a number of reasons. The size of the glass envelope.Where in the envelope the actual filament sits? If the filament is not in the right place, then the beam can be very odd looking - but in a Fresnel, you'd probably get away with it. Some of the smaller glass envelopes run much hotter. The ventilation and internal structure may well cope, but might not. The reflector could be too close, or other practical physical things can mess up. If the glass bubble is too big, then it's possible it could touch the front glass I some designs at certain focus positions - which could crack it. Look at the description of the proper lamp on the web, and only use lamps that are in the same category. Link to comment Share on other sites More sharing options...
Brian Posted March 19, 2013 Share Posted March 19, 2013 The bulb fits, ... It probably does. The reality is that there are only about 6 or so lamp bases in common use in the theatre and these are used on a huge range of lamp types and wattages. Link to comment Share on other sites More sharing options...
GridGirl Posted March 19, 2013 Share Posted March 19, 2013 IIRC, Selecon Acclaim fresnels and PCs use the same lamp, as do their big brothers the older SF1200 and PC1200 and the Rama fresnels and PCs. If the lanterns aren't from the same family though, you need to be a lot more careful, as others have said... Link to comment Share on other sites More sharing options...
Robin D Posted March 19, 2013 Share Posted March 19, 2013 The bulb fits, but my schools New Technologies manager had a rant at me about wattages 'n' stuff It sounds to me as if the New Technologies manager did absolutely right. It's worrying that you see it as a 'rant'. When lamps blow they can go quite spectacularly (and dangerously). It's clear from your question and subsequent response, that you have little understanding and you perhaps owe the manager an apology. They may not know all the answers themselves, but are clearly more much more risk aware than you. Ask the managers advice as they are on the spot with both luminaries, and the lamp in question. You never know, you might learn something other than if it fits, it must be OK. For example, Bell wire 'fits' into a 13amp plug, but it doesn't make it safe to use for mains! Oh... and next time you are unsure, its always much better to ask first. You will find that applies equally to the world of work. ;) Link to comment Share on other sites More sharing options...
alistermorton Posted March 19, 2013 Share Posted March 19, 2013 Bulbs grow, lamps glow. Any lamp will fit IF it's the right type -that means capsule shape, and filament size shape and rating, and base type and position. Oh! And burning angle as well. The bulb fits, but my schools New Technologies manager had a rant at me about wattages 'n' stuff Many lamps of different wattages use the same GY9.5 two pronged ceramic base, for example. The 1kW lamp from a cantata will fit in the holder of a minim (max rating 500W). So just because it fits it doesn't mean it's ok. Link to comment Share on other sites More sharing options...
paulears Posted March 19, 2013 Share Posted March 19, 2013 Some discharge lamps use very common bases - I never thought much about what would happen if you stuck an ordinary lamp in a discharge fixture - could be interesting? Link to comment Share on other sites More sharing options...
Brian Posted March 19, 2013 Share Posted March 19, 2013 ...what would happen if you stuck an ordinary lamp in a discharge fixture - could be interesting?Or not. As long as it doesn't strike, and without an ignitor it's unlikely, then nothing will happen. Link to comment Share on other sites More sharing options...
Rob Harris Posted March 19, 2013 Share Posted March 19, 2013 You might find this Linky of use in working out what lamp fits what.... Always better to double check and get it right first time! Rob Link to comment Share on other sites More sharing options...
adam2 Posted March 19, 2013 Share Posted March 19, 2013 If a discharge lamp is inserted in a halogen fitting then it is virtually certain that nothing will happen. All common types of discharge lamp used in the entertainment industry require a very high voltage to strike. Without an ignitor circuit to provide this, nothing will happen. If a working mains voltage halogen lamp is inserted into a discharge fixture then it will probably light at much reduced output since the ballast will limit the current/voltage to less than the intended direct from mains operation.In years gone by, inserting a filament lamp of roughly the correct wattage into a discharge fitting was sometimes recomended as a crude way of fault finding. If the filament lamp lights at reduced output then that suggests that the ballast was OK (ish) Full light output suggesting a short circuit ballast, and no light an open circuit ballast.This was a rather cheaper test than risking another lamp if the ballast was short circuit. Inserting a FAILED halogen lamp into a discharge fitting is actually the most dangerous combination. The ignitor circuit will "try" to strike the open circuit filament lamp and may well succeed in striking an arc between the ends of the filament. The lamp may then shatter with considerable violence. I would however strongly advise against use of any lamp other than the correct one. Link to comment Share on other sites More sharing options...
Brian Posted March 19, 2013 Share Posted March 19, 2013 ...what would happen if you stuck an ordinary lamp in a discharge fixture - could be interesting?Or not.As long as it doesn't strike, and without an ignitor it's unlikely, then nothing will happen. Of course, that is the wrong way around. Link to comment Share on other sites More sharing options...
jonathanhill Posted March 19, 2013 Share Posted March 19, 2013 Many lamps of different wattages use the same GY9.5 two pronged ceramic base, for example. The 1kW lamp from a cantata will fit in the holder of a minim (max rating 500W). So just because it fits it doesn't mean it's ok. 1kW lamps generally come in a GX9.5 or G22 format, and therefore cannot be fitted into a lamp holder designed for a GY9.5 lamp, such as to be found on the Strand Minim range. Link to comment Share on other sites More sharing options...
J Pearce Posted March 19, 2013 Share Posted March 19, 2013 There is the classic T19/T29 confusion, which can overheat reflectors and lenses as well as creating an interesting beam angle. I've also come across some older lanterns that couldn't handle 650W T26/27 lamps, only 500W T18/25. Unfortunately this wasn't discovered until after the weird alloy reflector had melted. Link to comment Share on other sites More sharing options...
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