How powerful generator is needed for this PA system
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  1. #1
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    Default How powerful generator is needed for this PA system

    We're going to have an open-air gig where we'll have to use electrical generator to power up our system. Here's the list of equipment we plan to use:
    - 2x EV ZLX12P
    - 1x FBT MAXX10SA
    - notebook with MIDI controller (source of music)
    - 2 or 5 channel mixer
    - lightmaxx cls-3

    I was wondering how powerful electrical generator should we get in order to make sure there won't be any problems? Where's the bottom end line in specifications? Could we actually damage the equipment if generator wouldn't output enough power?

  2. #2
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    Quote Originally Posted by krneki View Post
    We're going to have an open-air gig where we'll have to use electrical generator to power up our system. Here's the list of equipment we plan to use:
    - 2x EV ZLX12P
    - 1x FBT MAXX10SA
    - notebook with MIDI controller (source of music)
    - 2 or 5 channel mixer
    - lightmaxx cls-3

    I was wondering how powerful electrical generator should we get in order to make sure there won't be any problems? Where's the bottom end line in specifications? Could we actually damage the equipment if generator wouldn't output enough power?

    The controller and laptop are fairly nominal loads no more than 500W. The wattage of speakers don't mean much as you would base the power load on the amp(s) running flat out at there capacity; if active speakers you use the full volume loads loads of the inbuilt amps totalled together.

    Lighting load is dependant on what you are plugging in.

    You have to check for your set up but I'd typically look at
    DJ gear / laptop etc 500W
    Amps 2* 1000W = 2000W
    lighting at least 1000W but you need to add up.

    So for a reasonably small set up 3500W

    Generators are sized in kVA (S(kVA)=kW*pf) pf is power factor, assume 0.9 for your kit.

    So 3.5kW*0.9 = 3.9 kVA

    Generators have a step load change capability of typically 0.56 so yo want a bigger kVA rating than the kVA load. Probably get away with a 6kVA for the demand loads I've outlined above.


    If you can confirm the Wattage of everything you are using we can add them up here and check it for you.

  3. #3
    Tech Guru deevey's Avatar
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    I'd agree, with 3.5kw will give you a nice wide safety margin (I estimate quite a bit lower draw based on the gear specs).

    Equipment can be damaged by "Dirty" power and voltage fluctuations that can be caused by underpowered generators.

    Make sure whatever you get that its got a Voltage Regulator!

    oh and hire a monkey to watch the fuel levels.

  4. #4
    Tech Wizard Sleurhutje's Avatar
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    Like deevey says. Be aware that there are two kinds of generators. The cheap ones have a very nasty waveform on the output, some not even a sine wave but a two or three step block wave. This might cause annoying side effects to your audio outputs. The more expensive generators have a so called inverter (the voltage regulator that deevey talks about) which creates a sine wave shaped output voltage and will not cause any problems.

    Before buying or renting a generator it's advised to test the equipment first.

  5. #5
    Tech Guru deevey's Avatar
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    Quote Originally Posted by Sleurhutje View Post
    The more expensive generators have a so called inverter (the voltage regulator that deevey talks about) which creates a sine wave shaped output voltage and will not cause any problems.
    An inverter converts and increases voltage from the alternators low DC output to usable AC mains voltage, all small generators with a mains socket have one built in.

    However it is not the same as a power regulator or stabilizer which keeps the mains voltage at a safe equipment threshold, some generators have one built in, some do not.

    http://www.amazon.com/Simran-AR-3000...age+stabilizer
    Last edited by deevey; 08-11-2014 at 11:26 AM.

  6. #6
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    Don't you love it when you ask a question, hoping to get a good response, and instead you get some helpful answers but it's mixed in with a whole bunch of intellectual nonsense you have to decipher. PF on single ph load etc....

    In any case, 3.5kw is a very very safe load calculation for your equipment. Just make sure to let the rental company know that you are running electronics like computers with the generator, and they should point you in the right direction. They should point you out to something thats rated a little higher then your 3.5kw, if not consider that each 1kw is about 8.5 amps US 120 volt or 4.5 amps EURO
    220 volts. I personally would feel very safe with anything around 5kw rating.

  7. #7
    DJTT Moderator Dude Jester's Avatar
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    Quote Originally Posted by deevey View Post

    oh and hire a monkey to watch the fuel levels.
    worst job ever
    Acer E5 i7 16GB 512SSD 2TBHD ~ WIN 10 ~ TSP 2.11 ~ AUDIO 6 ~ DUAL X1s ~ DN-X1600 ~ SPECTRA ~ TWISTER ~ ATH-PRO500 MK2 ~ ZED6FX ~ AT2020

    " Iím the Dude, so thatís what you call me. That or, uh His Dudeness, or uh Duder, or El Duderino, if youíre not into the whole brevity thing. "

  8. #8
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    Quote Originally Posted by Jester View Post
    worst job ever
    Shut it, monkey!

  9. #9
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    Maybe I could get Honda EU10i and EU20i, so I was thinking to power up 1x FBT MAXX10SA with EU10i and everything else with EU20i (2x EV ZLX12P, notebook and mixer). Lights are optional. Do you think that could work? Could there be any grounding issues?

    In fact I could even power notebook and mixer with 12V to 230V inverter from accumulators. In that case, it would look like this:
    EU10i: 1x FBT MAXX10SA
    EU20i: 2x EV ZLX12P
    1000 W 12-230V inverter from acc: notebook and mixer

    What do you think guys? Is that combination rock-solid?

  10. #10
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    Rock solid?.....no. I would say just enough at full blast. Grounding issues could be a real possibility considering there are three different power sources. This is just my opinion based on the facts given though. Best of luck

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