tlc Posted February 3, 2009 Share Posted February 3, 2009 We have several Betapack 3 At the end of 20m of socapex they are loaded with 2 x 1kw parcans. On fast chases the breakers trip out. Breakers are "c" type so should take the surges from cold.20m of soca does put in a reasonable bit of resistance to help hold down cold start surges (even on 2.5mm which is what we are using.) Local distro is on 30 metres of 16mm SWA from main incomer, so again a reasonable cable length to help hold down the surges. (at the risk of answering my own question)I suspect we suffer from having a large local transformer adljacent to the building giving a very low source impedence to our supply. (3 x 2000 amp incomer to plant room) Now we could turn up the preheat to glow the pars but I dont really want to do this to the extent filiments are visibly glowing. Short of swapping to "d" type breakers (need to check if line is low enough loop impedance to do this within regs) anyone got any suggestions.We have dropped to 2 x 1/2 Kw lamps on some of the worst channels for this problem. Swapping betapacks for fuse protected dimmers we have no problems so reasonably sure its the mcb surge sensistivity that is the problem. Link to comment Share on other sites More sharing options...
Keeper of the Keys Posted February 3, 2009 Share Posted February 3, 2009 IIRC preglow at 5% will not show.... Link to comment Share on other sites More sharing options...
ian.michael.williams Posted February 4, 2009 Share Posted February 4, 2009 Had this problem before when working in a venue down south... just add a little preheat to all channels and your tripping woes are a thing of the past! Link to comment Share on other sites More sharing options...
tlc Posted February 4, 2009 Author Share Posted February 4, 2009 We have found that we get a fairly high filament noise on our preheat , once 100 pars are all on 5% preheat there is a very obvious noise from the grid due to this. While acceptable for rock n roll where the PA is running high it is not ok for other types of show. Also 5% preheat on a very large number of channels does draw a reasonable amount of power from the supply. Our dimmers are on 24hrs a day with no easy central isolation for them. (distributed dimming in our building). Trying to be "energy efficient" this is not an ideal solution. Link to comment Share on other sites More sharing options...
peter Posted February 4, 2009 Share Posted February 4, 2009 Hi TLC. I'm slightly confused by how 20m of Socapex is "distributed dimming" but nontheless.... The C type breakers fitted to the Beta3 (Hager branded) are standard off the shelf DIN rail mounted breakers - you would see the same behaviour if these breakers were fitted to a distribution board or any other dimmer (The Betapack is performing as designed). As others have said it is the inrush current which is causing the breaker to trip, which is primarily due to the cold filament warming, but could also be due to the supply voltage, impedance of the 20m cable run, etc etc. Fast Chases are a problem in these sort of situations because you're trying to warm and cool the filament over a short time. I'd suggest programming the "off" level to a preheat level (5%, maybe higher) rather than blackout. You might find a slight fade rather than a snap in the chase will help as well, giving the channels time to warm and cool rather than snapping them. And of course, if you swap Pars for other fixtures, the filament sing problem will be significantly reduced. If the MCBs still cause you problems, it's possible to obtain DIN rail mounted fuses in the same size enclosure as the MCBs, which you could retrofit. The Betapack 3 will only apply a preheat to your channels when DMX is present, so as long as your desk is off (or any buffering devices downstream) then you won't be wasting as much energy as you think. Some consoles (Strand 500 series comes to mind) offer a pre-heat function from the desk, which is relative to your cue list - only preheating just before the channels are needed. I hope some of the above helps, Link to comment Share on other sites More sharing options...
tlc Posted February 4, 2009 Author Share Posted February 4, 2009 I'm slightly confused by how 20m of Socapex is "distributed dimming" but nontheless.... It is the betapacks that are distributed , not the outlets per socapex.We have many betapacks at locations throughout the building each on average connected to about a 20m socapex , there is no central point to switch off the betapacks , we would need to climb around the roof to isolate each pack. A central location with a rack of dimmers could simply be isolated locally when not being used. The situation arose from slowly upgrading channel count over the years , new channels being added a rack at a time the rack being installed local to where the new channels were to be used.Apparantly this was the cheaper option at the time.We do have a rack room where the "original" dimmers are installed. By original we are talking antique here (Strand JTM / STM)I would much prefer the system was upgraded to the more normal central location for all dimmers. We have considered retrofitting fuses in place of the MCB, but reluctant to go down that route as MCB do make life easier (in general) The large transformer 20 metres from our plant room is probably the source of our surges being so large.At the far end of the site (300 metres from the plant room) there is no tripping problem.It is the racks close to the main incomer that have the issue. It is not the Betapacks at fault here , its just the local site that is making conditions slightly awkward. Link to comment Share on other sites More sharing options...
Keeper of the Keys Posted February 5, 2009 Share Posted February 5, 2009 (...)Our dimmers are on 24hrs a day with no easy central isolation for them. (distributed dimming in our building).(...)I was always taught not to leave dimmers on over night when not in the venue (or when you leave the touring location etc.) as it's a firehazard... Link to comment Share on other sites More sharing options...
tlc Posted February 5, 2009 Author Share Posted February 5, 2009 (...)Our dimmers are on 24hrs a day with no easy central isolation for them. (distributed dimming in our building).(...)I was always taught not to leave dimmers on over night when not in the venue (or when you leave the touring location etc.) as it's a firehazard... In an ideal world this would indeed be the case and if we had a central point to isolate we possibly would. The only time we fully power down is when we close for holiday periods. The rest of the time we rely on our fire detection system to flag up any problems. We also do make periodic checks on all the dimmers and distribution after the rig has been left "all up" for 20 minutes.This has allowed us to detect a few hot connections before they develop into larger problems. We do have central isolation for all our movers and these are powered down when not in use. Link to comment Share on other sites More sharing options...
Biskit Posted February 5, 2009 Share Posted February 5, 2009 I suspect we suffer from having a large local transformer adljacent to the building giving a very low source impedence to our supply. (3 x 2000 amp incomer to plant room) Slightly different take on this... being so close to a transformer means you may have higher supply voltage than you should. Given that your lamps are probably 230V or 240V rated, if your supply is over, say 250V then the inrush current will be even higher than normal, hence you are tripping breakers. You may also notice shorter lamp life. 1. Check mains voltage at incomer if you are able to do so safely, or have a sparky do it. If it is over 253V on any phase to N, you should contact your distributor, as they are obliged to supply you 230V +/- 10%*. 2. Check what voltage lamps you are using. If you are using 230V, 240V ones may ease the issue slightly. *I believe this is correct now... I know it used to be +10%/-7% at some point. The reason you sometimes get higher when near a transformer is the distributors tap the windings allowing for voltage drop in the low voltage cable to individual premises, so to make sure voltage at the building farthest away isn't too low, the voltage as the line leaves the sub-station is as high as allowed. If it is too high and causing you issues, that is their problem not yours! Link to comment Share on other sites More sharing options...
tlc Posted February 5, 2009 Author Share Posted February 5, 2009 Slightly different take on this... being so close to a transformer means you may have higher supply voltage than you should. Given that your lamps are probably 230V or 240V rated, if your supply is over, say 250V then the inrush current will be even higher than normal, hence you are tripping breakers. You may also notice shorter lamp life. Depending on time of day (we have electric heating system) our line voltage can be as high as 242volt close to the incomers. Generally it sits around 237volts. The DNO have tapped the transformer correctly , this is well within specifications. I think I'm correct in saying the transformer only feeds our facility. Link to comment Share on other sites More sharing options...
tlc Posted February 5, 2009 Author Share Posted February 5, 2009 The Betapack 3 will only apply a preheat to your channels when DMX is present, so as long as your desk is off (or any buffering devices downstream) then you won't be wasting as much energy as you think. Thanks for thatI had not been aware of this and I can verify that this is indeed the case , a very sensible feature. When I have used preheat on older units it was always up as long as the dimmer had power connected. (serves as a good reminder to always read all the way through the manual) Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.