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16 Mar 10 - 01:12 AM (#2864996) Subject: Tech: Using a generator at gig From: Herge Hi We are playing at a wedding in a Marquee soon - the organisers have asked us how much power we require from the generator for us and DJ to follow. We use a Bose L1 Model 2. Any suggestions? |
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16 Mar 10 - 01:37 AM (#2865003) Subject: RE: Tech: Using a generator at gig From: JohnInKansas In the US: Multiply the number of connectors you plug in to run all your equipment by 20, and then multiply by the line voltage at the socket - usually 120. The result will be the maximum number of watts required. (This assumes each of the outlets are at the common 20 amp rated capacity, on a 115 or 120 Volt line.) Anywhere in the world: For better accuracy, you can add the "maximum input watts" (for the power input, not the signal plugs) on the nameplates of all the pieces you'll plug in. You can also multiply max amps x line voltage to get the watts for those that don't quote watts directly. Then (in either case) add all the watts. Either of these will be a fairly conservative estimate, since all your plugins won't likely draw maximum power at the same time - and/or you may be sensible enough not to run everything at maximum; but "derating" may be risky if you only have a few plugs running. If you can plug more than one device into a multi-socket outlet that has all the sockets on the same circuit breaker, you can use the number of "breakers" instead of the number of plugs, which may bring the estimate down some too. John |
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16 Mar 10 - 03:11 AM (#2865019) Subject: RE: Tech: Using a generator at gig From: rangeroger Herge,I went to the Bose web site and found the specs for your system. It shows 500 watt draw at either 50/60 Hz 120V (US)or 50/60Hz 230V (Eur). A single 20 amp outlet will be all you will need for power. Be sure to use a heavy enough extension cord (minimum 12gauge wire) from the generator to your system. The specs showed a 32amp maximum inrush current. This will be only momentary when you switch on so you dont want to lose ampacity with too small or too long an extension cord. If any other power using device is on the same circuit make sure it is off when you switch on. BTW the above specs are on page 21 of your user manual. How do you like the Bose system? Everything I've read about them point to an awesome PA system. rr |
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16 Mar 10 - 10:08 AM (#2865230) Subject: RE: Tech: Using a generator at gig From: GUEST,Graham Bradshaw The easiest way to calculate is to find max Watts and divide by voltage. So in this case, its 500 divided by 250 = 2 amps. Also, you'll probably find the fuse on the mains plug is 5 amps, so that is the absolute max.(If there is a 13 amp fuse, then it needs changing to the lower rating as 13 is not protecting you. Your gear will have blown up before the fuse kicks in) Don't forget any backline amps or keyboards will all add to the load. But in the UK, you'll be well within a 13 amp socket. Most generators will have 16 amp or 32 amp Ceeform outlets (blue industrial connectors - NOT the yellow ones - they are only 110v), so you'll need the generator people to step you down to a 13 amp socket so you can plug in your system. G |
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16 Mar 10 - 10:41 AM (#2865244) Subject: RE: Tech: Using a generator at gig From: mandotim From experience, the Bose will be fine with a standard 13amp supply, but Graham is right about the fuse. Are there lights on the same circuit? If so, watch the overall loading, things like ParCans take a big current. How big is the marquee? One Bose should be ok for small ones, but we played a big corporate marquee gig a while ago, and we needed two Bose towers plus three bass bins. |
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16 Mar 10 - 01:17 PM (#2865379) Subject: RE: Tech: Using a generator at gig From: Bernard Make sure you check the generator is running at the correct voltage and frequency before you plug sensitive equipment in, or expensive damage could occur. We once had an issue with a three phase generator system where one of the three phases was 'motorboating' from the other two. Fortunately we checked everything, so nothing was damaged and nobody got hurt - a serious consideration with three phase in particular. Check that there is a decent earthing spike, too. |
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16 Mar 10 - 01:55 PM (#2865402) Subject: RE: Tech: Using a generator at gig From: PoppaGator How LOUD is that generator gonna be? (Something to keep in mind...) |
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16 Mar 10 - 03:03 PM (#2865442) Subject: RE: Tech: Using a generator at gig From: Herge Wow you guys know your stuff - we are really please with the Bose, although we notice it needs to be set up high as the sound can get absorbed by dancers and not reach the back of the hall. |
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16 Mar 10 - 07:26 PM (#2865640) Subject: RE: Tech: Using a generator at gig From: Bernard It's a popular misconception that the fuse in the plug top is there to protect the equipment... it isn't. It is there to protect the CABLE feeding the equipment! There should be another fuse on the equipment itself (or possibly an MCB - Miniature Circuit Breaker) which is intended to protect the kit. If the manufacturer has specified a 2 amp T fuse (always written by the fuseholder), it should not be replaced with a quick-blow (F), or you'll be forever changing them (or think you have a fault). Most modern kit uses a torroidal mains transformer, and typically needs a slow-blow, because the start-up current drawn by a torroidal can be significantly higher that the maximum current the equipment actually uses. So it may even be correct to use a 13a plug top fuse, too. If in doubt, check with the manufacturer. It's surprising how many people bring a 'faulty' amp in for 'repair' only to be educated about using the correct grade fuse! |
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16 Mar 10 - 09:24 PM (#2865699) Subject: RE: Tech: Using a generator at gig From: GUEST,open mike hopefully the noisy generator will be a distance away and insulated to prevent sound pollution but the line loss over distance can also be a problem. it is best if lines carrying power and lines carrying signal (audio and or video) are at least 12" away from each other to prevent interference. good thing the organizers are offering to provide power. i recall a thread hear a while back from some folks who were playing a wedding and did not have power available. |