Using Generators

[ollygeorge 0]

Just had the question asked of me by one of my booked marqees for the summer how much power will i be using???

 

I have not got a clue, but im guessing the main items that are sucking the juice are the amps and lighting effects??

 

Can anyone give me a guestimate of how much i will be wanting running ruffley the following

 

One 800 watt RMS RSE AMP

One EP2500 Behringer Amp

Two 250 watt lighting effects

Four 120 watt lighting effects

Smoke machine

 

I also run cd players, mixer, md, crossover, mic, star cloth, lamp, pin spots, mirror ball, but i dont think these use a lot.

 

Cheers in advance

 

Olly http://www.dj-forum.co.uk/html//emoticons/thumbup.gif

[brianmole 0]

I suggest you check the power consumption specs in the manuals for each device, add them up, bingo.

 

Roughly:

One 800 watt RMS RSE AMP = 800W

One EP2500 Behringer Amp = 2500 W

Two 250 watt lighting effects = 500W

Four 120 watt lighting effects= 480w

Smoke machine = about 750w

say 200W for mixer, cds, etc..

 

Total about 5.3KW, I would ask them to provide 2 x 13A feeds, should be plenty more than you need.

[norty303 0]

Don't forget that amplifiers don't draw anywhere near their wattage rating in normal use. If this was the case we'd all get away with running a whole lot less than we actually do off a 13A socket. It takes twice the amount of power to get a 3db increase so by running 1 led less (assuming its an accurate 3db scale) is actually pulling a whole load less power.

 

e.g. I was running 7kw of amps off a single 13A socket flat out for a long time.

 

7000w/230v = 30.43A but how can this be i hear you cry!!!?

 

One of the main things you need to consider is the smoke machine as this will spike hard on warmup and in use and may well be your biggest problem on the night, depending on the size of it.

[brianmole 0]

If you do this, don't forget to turn on everything in turn, not all together!

[DJ Marky Marc 0]

QUOTE

Don't forget that amplifiers don't draw anywhere near their wattage rating in normal use

 

ture but dont forget that murphys law says that at your biggest gig of the year when it all matters and the people are watching you somthing will and can go wrong so by giving your self some head room you reduce the risk of somthing going wrong....

 

I state a minimum of 2 un-shared 13amp sockets on my contract....

 

also with generated power its good to have double what you need..

 

so if your system adds up to 5000watts and you need a 10k generator as the are notorios for being unstable...

 

and dont forget that the bar and food people will want to run fridges and beer pumps from your power and they wont tell you......

[Gary 0]

I'd turn the maths on its head.

 

At a normal indoor gig, how many wall sockets do you use? Remember to count double sockets as "2".

 

For an example, lets say you use 4 single sockets (or 2 double sockets) - in this case, I'd tell the organisers that you need (4 x 13amps = 52amps, which is approx 12 kilowatts)...about the same as 4 fan heaters.

 

Unless you're blowing fuses regularly at your gigs, this calculation should give you peace of mind.

 

What I would stress to the organisers is that you need to have a generator where no other power users are sharing (its a bit hopeful, but you can always ask). I was once using a generator, which was being shared by several other users and when the beer tent chillers went on, all the illumination on my CD players, technics, and gooseneck light dimmed badly. The generator was huge (about the size of a caravan) but it took several seconds for it to adjust to changing power loads. Not ideal for electronic gear.

[YourBigEvent 0]

I was ran my power off the electric gates to the house, great until the gates opened or closed, but as it was the only source they had to put up with it.

[ChrisPointon 0]

Unlike the Marquee Wedding I had last week in Buxton. In the back of somebodies back yard with several 60W x 5 bars of spot lights, The Band, 3x 500W Floodlights on tripods and us, all expecting to be run off one extension lead from the Garage http://www.dj-forum.co.uk/html//emoticons/rolleyes.gif .

 

Fortunately I had a long enough extension lead to run from the Marquee to a seperate socket in the Kitchen, so whatever happened to the Band if the 13A fuse blew wasn't going to affect us! http://www.dj-forum.co.uk/html//emoticons/wasntme-sign.gif . Full marks to whoever erected the Marquee and the subsequent 'Power' arrangements, for running the extension lead right across the only Entry / Exit into the Marquee - it tripped up quite a few little brats during the course of the Evening! http://www.dj-forum.co.uk/html//emoticons/221.gif

 

 

[brianmole 0]

QUOTE

all expecting to be run off one extension lead from the Garage

 

Everyone here will tell you of a bad experience running off a long ext lead in the house.

 

Can't stress this enough - if you are in a marquee, INSIST they either use an adequate professional generator, or INSIST they call in an electrician to plumb in to the house electrics, so you have a stable supply at their own cost.

 

Also invest in some kind of earth spike to plunge into the ground near where you set up and connect to an earthing point in your systems. This should save you getting a claim on your pli for electrocuting the guests or yourself.

[ChrisPointon 0]

Also when adding up the ratings, make allowances for losses and Power Factors of inductive loads. There are also losses as heat and the power draw of other internal components to take into consideration. Taking a 250W lighting effect as an example - it may display anything between 270 and 300VA as it's true inductive loading on the rating plate - just because it has a 250W lamp doesn't mean you should mark it as drawing 250W!.

 

Also take into Account the Surge at switch on of any Amplifiers without Soft Start, they can trip sensitive RCD's and Blow weak fuses at the end of long leads due partly to the voltage drop along the cable length of very long cables.

 

Ideally even Temporary Marquees should have a safe, realible power feed of ideally 4mm SWA from the House Distribution Board and fitted by an Electrician. However for the thrifty client, this is yet another expense and the temptation to bypass common sense by digging out their old flymo lead and begging extension leads from the neighbours is usually the norm. This is why it is important to be prepared yourself, and if the power facilities aren't up to scratch then refuse to connect to them.