Marc-Engineer Posted January 6, 2011 Posted January 6, 2011 Jst for your info, if you are using a ladder they (acording to H& S E) you can only work from a ladder if the job you are doing only needs one hand you must have one hand on the ladder at all times, we use 2 man ladders with 2 opratives its the only safe way with out using a tower. And as said above, if it has been wrongly fited so the lamp cant be removed with out removeing the unit from its mount or part of its mount you have further problems, but what ever you do DO NOT OVER RUN THE LAMP its the biggest killer of projectors. Marc Projector Engineer
HallX Posted January 6, 2011 Posted January 6, 2011 DO NOT OVER RUN THE LAMP its the biggest killer of projectors. Out of curiosity, why? Paul
Chris_Cook Posted January 6, 2011 Posted January 6, 2011 I love the way working at heights is treated as this dark mysterious art. I wonder on average how many people it takes to change a light bulb in a school? Especially once you include those who do the H&S paper work, order the bulbs, sort out financing, insurance, training etc.
Marc-Engineer Posted January 7, 2011 Posted January 7, 2011 (edited) Hi Paul, the way lamps operate is often not understood you wont of course remember but during the WW2 we used search lights very large reflectors using 2 largs rods between which jumped a spark, this was a huge (bear with me) this produced a huge amount of light to light up aircraft in the sky. Ok now our little projector lamps are very like these, the large search lights had motor driven rods so as they burnt down the where driven together to keep the gap constant (impotant bit). Our little lamps cant do this so the gap gets bigger, so what the projector does is turn up the voltage in an attempt to maintain brightness over its life as the rods get eaten away (no one asleep yet?) So this has 3 downsides with larger gap the heat goes up as its a bigger spark and funnily enough it is not the heat that burns the LCD and polerising panals it is the UV light that increases exponentialy the third thing is the current goes up from the power supply with the attempt to maintain the brightness (nearly there). The power and ballest unit the control the lamp become stressed if they work too hard, by over running the lamp as the gap becomes to big so next lamp in will not be as bright due to the powersupply /ballest being stressed the first time (cost to replace ballest depending on unit £250 plus) and the UV may have dimmed by burning the polerising filters (yellowing). So moral of the story DONT DO IT, change your lamp at around 2500 hrs regardless of how bright YOU still think it is and DEFINATLY DONT wait till it doesnt light anymore as this is way too late. A maintained projector should easily last 7 to 8 years. Marc Projector Engineer Edited January 7, 2011 by Marc-Engineer 3
SimpleSi Posted January 7, 2011 Posted January 7, 2011 Nothing will happen re this issue until someone hurts themselves badly and the HSE get involved and then a big letter will go out to all LAs/schools and then everyone will be very good for a while and then things will return to being unsafe (As per the site supervisor who fell and seriouslty injured themselves a few years ago - TAs are back to standing on desks in high heels putting up displays!) regards Simon
HallX Posted January 7, 2011 Posted January 7, 2011 @Mark-Engineer Many thanks for the detailed explanation, I've passed the info to our AV techie who was unaware of this. BTW, how may aircraft did you shoot down in the war Paul
soveryapt Posted January 7, 2011 Posted January 7, 2011 I used to call on people to help, but the school have sent me on ladder training now (what a waste of a day that was, but hey, I have a piece of paper now that officially says I can use a ladder, just like I have been able to since I was about 12/13 when I used to help my dad out. lol .. Generally, it only needs a small step ladder, and in that case I'm able to get it down fairly safely, it's when I'm 4 rungs+ that I get an additional pair of hands in to help ..
sparkeh Posted January 7, 2011 Posted January 7, 2011 Depends what school I am at. At one the PO would not help me in a million years :/ , second school the PO helps if I need another pair of hands, at the third school the PO and his assistant do all the replacements for me
soveryapt Posted January 7, 2011 Posted January 7, 2011 @Marc-Engineer - that will do for my "you learn something new everyday" bit .. lol ..
Marc-Engineer Posted January 7, 2011 Posted January 7, 2011 @Paul i rember back when ships where made of wood and men where made of steel, and a lot of people in our town had a tattoo of an Ancor on their bare arms, and so did some of the men. Marc Projector Engineer
HallX Posted January 7, 2011 Posted January 7, 2011 a lot of people in our town had a tattoo of an Ancor on their bare arms, and so did some of the men. lol. My kind of gal!!
quietriot1983 Posted January 12, 2011 Posted January 12, 2011 "Ladder Training"??? More waste of money. Where is the 'facepalm' smiley?!
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