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GENERATOR HELP

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freddymendez View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote freddymendez Quote  Post ReplyReply Direct Link To This Post Posted: 06 February 2017 at 10:31am
sigh
120-140 bpm, pianos and bass.
diesel, the fuel of professionals.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Earplug Quote  Post ReplyReply Direct Link To This Post Posted: 06 February 2017 at 12:52pm
Originally posted by Jasonstry Jasonstry wrote:

For about £10 or so you can buy a meter that plugs into a wall socket and that has a socket for you to plug into. You will find them on Amazon and ebay. They aren't exactly precision instruments but they will give you a good idea of the voltage available and how much power you are drawing. Most people are amazed (and, often, a bit disappointed) to learn how little power their gear is using. I have bought several of these as they keep vanishing at gigs.... 


I'd be carefull with those meters, especially if you then spec a generator based on what you see. They show some average power/current draw, integrated over a second or more, nothing to do with the true peak current spikes that you might have. As noted above, when dealing with with gensets, the bigger, the better.


Edited by Earplug - 06 February 2017 at 12:53pm
Earplugs Are For Wimps!
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snowflake View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote snowflake Quote  Post ReplyReply Direct Link To This Post Posted: 06 February 2017 at 12:55pm
when using amplifier powers are we working with spec sheet burst output power, RMS max output power (measured over what time period), or max electrical input power - usually on the back of the equipment? the difference between first and last can be a factor of four or more.

are some amp classes inherently more generator friendly? class A has such high quiescent current that no dummy load would be needed I guess - but so inefficient you would need a bigger generator anyway. how do other topologies and power supply combinations work with generators?

cheers
Phil

Originally posted by shagnasty shagnasty wrote:

Originally posted by freddymendez freddymendez wrote:

you probably won't need as much as you think you'll need, your amps figures are likely to be inflated and of course they won't be drawing the full amount for the full time, like say a heater or a light would.

you'll probably be okay with a 6.5kVA diesel (go for one with yanmar, lombardini or lister engine, and meccalte, sincro, markon alternator). but i'd look at switching out that matrix mf because without PFC it will draw big peaks which could limit you somewhat.

by the way you can fill a petrol genny whilst running but i wouldn't recommend it. however petrol are a lot cheaper and you can get higher output for your money. maybe you could switch off momentarily to fill up? (heh ;))
couple it with one of these and you can box off filling it up really quickly:

if going petrol look for honda gx390 for 6kva output, or honda gx610 or above for around 10 kva.  loncin engines are also good. again look for meccalte alternator or one of the above i mentioned.

Bolox!!!

Just BOLOX

NEVER use a shit-box genset with less VA cap than you amps have... END OF!!!

In real terms a 25KVA as suggested, is about where I would go, you list 10.6KW of cheap SMPSU amps that will cause havoc with a most gensets due to something called current distortion, I would go 20KVA plus with decent AVR ( the Deepsea kit looks after the engine and monitors the rig but still needs a decent AVR, in real terms DSC has no effect on power quality)  I would stuff 2x 3KW fan heaters (or 6 Mac500s) on the set to ballast load it (gens do 30> 80% load snatches really well, 0>50% very badly, give the system something to chew on (even really good sets have shite regulaution below 12%) also bear in mind a 20KVa set will have a 0.8 power factor (ish) so only 16KW, add to that teh agressive nature of your load (thinking Matrix def use 6 pulse inversion) you could easy see a 50% KVA > KW derate....

Get a decent machine and not replace it or yours amps every other gig...

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MattStolton View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MattStolton Quote  Post ReplyReply Direct Link To This Post Posted: 07 February 2017 at 11:07am
Originally posted by snowflake snowflake wrote:

when using amplifier powers are we working with spec sheet burst output power, RMS max output power (measured over what time period), or max electrical input power - usually on the back of the equipment? the difference between first and last can be a factor of four or more.

I am lucky, in that pretty much everything I run is QSC, therefore there is a spec sheet for each range, that tells you real world measured current draw at 120 and 230V, for 8,4 and 2 ohm, and a range of drive, so idle/quiescent, 1/8 (approx 6db before clip), and some higher level which is basically clip limiters cutting in (1/3 power), and then "take the piss clipping the crap out of it with sine waves" clipping.

Here is RMX series sheet.

I have another sheet for PLX, they do one for PL, etc.

I have verified their figures for PLX (S1) on a customers install, with a PLX3402 and clamp meter, and was in-line with there published figures, so I am happy to trust them all. Been to a large number of QSC talks to dealers, and they keep going on about what there figures actually mean, how to compare "there figures with competitors, fairly, so you are comparing apples with apples" type conversations, and have no great issue with any published figures. Well, with RMX, PLX, PL, at least.

You know what you are going to hang of each channel, you kinda now in advance how hard you may have to push things, so is a good way of forming a best guess to real world current draw.

Add as much headroom as you can afford, and get gen-set to suit, allowing for a bit of load-banking to get things into sweet zone of gen-set generation, and to dilute PF.

Because I am such a pussy, and can't afford new drivers after every gig, I am well within the 1/8 power range, but estimate power requirements at half way between 1/8 and 1/3. Then allow 25% of resistive tungsten, and order gen set.....

I am lucky, in that I have a number of quite trusted sources to hire half decent gear from, and I always carry the basics to give a dirty filter a clean, etc, if something is found to be wanting. I own Alfa Romeos, so getting under a bonnet does not scare me!

I also have half a clue (no expert by any stretch) on distro, and the basic concepts of why we fuse, why we use the CSAs we do, and how to do things safely. Again, when my own shelves don't have exactly what I want, I have accounts with a couple of hire peeps that specialise in just distro, and just get it in to suit.

My distro is max 32A SPN+E, because my size of gigs are typically less than 32A. On bigger stuff, I bring in 32A TPN+E, or 63S/TPN+E to suit, because, and here is the rub people, I do actually plan what the fook I need to take to the gig, to do it safely and properly.

By planning, and it really is often no more than back of fag packet, you know what is required, the rest of your crew know what they need to test in advance, and then what they are going to do, once they get to site. For the sake of 30 mins of pencil on paper, you can save hours on site.




Matt Stolton - Technical Director (!!!) - Wilding Sound Ltd
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shagnasty View Drop Down
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Post Options Post Options   Thanks (1) Thanks(1)   Quote shagnasty Quote  Post ReplyReply Direct Link To This Post Posted: 08 February 2017 at 12:58am
Not too much for quoting regs (in particular on here as everyone knows a load more than about power and they all have a mate that is a "sparks" ) because most of the time I read documents and give them less than 6 marks out of 10, but understand the laws of phyics can't be fu!ked with and WILL bite your clueless, retarded ass.


If you have n incident and your only data is you tried ti on a 13A plug so ....... welcome to hell.

I personally believe stupid people should be culled to stop their worthless DNA poluting the Gene pool...

But if you like extreme sports crack on, with luck you will die soon and kill no-one...
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snowflake View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote snowflake Quote  Post ReplyReply Direct Link To This Post Posted: 08 February 2017 at 1:01am
this is a bit more than the OP asked for and some of it is over my head but I thought it was relatively accessible:


suggests that there may be very significant differences in power factor between amps with and without active PFC - which would have a major effect on the size of generator needed.




Edited by snowflake - 08 February 2017 at 1:05am
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WILLZTHRILLZ View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote WILLZTHRILLZ Quote  Post ReplyReply Direct Link To This Post Posted: 08 February 2017 at 4:53am
lister-diesel-generatorlister-diesel-generator
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WILLZTHRILLZ View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote WILLZTHRILLZ Quote  Post ReplyReply Direct Link To This Post Posted: 08 February 2017 at 4:54am
Great in its time ,,,but not quite what yer lookin for.
Will

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Post Options Post Options   Thanks (0) Thanks(0)   Quote WILLZTHRILLZ Quote  Post ReplyReply Direct Link To This Post Posted: 08 February 2017 at 5:06am
Also, I don't want to get involved in this but if my meter says 10 volts(rms) ac, that's 14.14 volts dc.
There's a lot more power available with constant current hence the necessity for thicker wires.
Shoot me down, go on. Dead
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Post Options Post Options   Thanks (0) Thanks(0)   Quote WILLZTHRILLZ Quote  Post ReplyReply Direct Link To This Post Posted: 08 February 2017 at 5:31am
@ freddymendez, petrol is Not cheaper than diesel.


I run my big compressor (4gallons/hour) on 'gas oil'   (red diesel) and the last batch was 71p/litre from Imperial oils 5 weeks ago
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WILLZTHRILLZ View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote WILLZTHRILLZ Quote  Post ReplyReply Direct Link To This Post Posted: 08 February 2017 at 5:40am
When I get around to re-engining in my wee genny, (goin for OVLOV FL6) I'll be looking at 40+ litres per hourCry
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Post Options Post Options   Thanks (0) Thanks(0)   Quote WILLZTHRILLZ Quote  Post ReplyReply Direct Link To This Post Posted: 08 February 2017 at 6:45am
Gas oil, (red diesel), the fuel of professionals.
Now who said that?
Otto would turn in his watery grave if he knew that we were feeding his engines on fossil fuel, they were designed to run on peanut oil.
Will  
gie me red till am ded

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