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Author Topic: Generator suggestions  (Read 3623 times)

Russell Ault

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Re: Generator suggestions
« Reply #50 on: July 01, 2019, 03:58:12 pm »

Somewhere earlier it was mentioned that the 50a 240v California connector was essentially turning that into 100a at 120v. 

Why,  on this mq7000, wouldnít the 25a 240 California connectors deliver 50a at 120?

This generator specifies that it can make 50a at 120v.  Thatís what I need - how do I pull all avail power with this genny?

To the best of my knowledge, there's no such thing as a 25 A California connector, they're all 50 A. In this case, the California connector is capable of handling almost twice the power that your generator is actually capable of producing. The NEMA L14-30 is also capable of handling the generator's full power, but allows you to use thinner cable (since, for safety, the cable should be spec'ed to the capabilities of the connectors, even if actual intended usage is lower).

Just to be clear, the current-carrying capacity of all connectors (not just California connectors) is specified per contact, so a 50A California connector means 50 A for each Hot and the Neutral, a NEMA L14-30 is 30 A for each Hot and the Neutral, etc. So for example, a NEMA L14-30 is rated for 30 A of 240 (or 208) V power between the two Hots (called Legs), OR rated for 30 A of 120 V power between each Leg and the Neutral, for a total of 60 A of 120 V, OR some combination of the two (e.g. 10 A of 240 V power and 40 A of 120 V power split evenly between the two legs).

In your case, to access the full 6000 W that you're generator can produce as 50 A of 120 V power you'll need a distro that can take in up to 30 A of 240 V power and break it down into four 20 A 120 V circuits, two for each Leg. Of course, your generator is only actually capable of continuously producing 25 A of power per Leg, meaning that you won't be able to load all four 120 V circuits to 20 A. For example, If one 120 V circtuit is loaded to 16 A, the other 120 V circuit attached to the same Leg will only have 9 A of power left available to it, and attaching a larger load might pop the main breaker on the generator even though you'll be well under the breaker limits on the distro.

-Russ
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Dave Guilford

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Re: Generator suggestions
« Reply #51 on: July 01, 2019, 05:43:18 pm »

The unit you selected will supply 30 amps at 240 volts, so according to the power law:

30A*240V=7200W

You need a bigger generator. Probably something like 15kW, which is the next size up.

50A*240V=12000W


VxA=P

This ties in to my earlier post about sizing your genset correctly, since you need to be pulling a >40% constant load to avoid wet stacking.

You should really really talk to a generator pro to help you get it right.

Well brad thatís exactly what I was trying to do and it seems Iíve been given lousy info earlier in this thread.

Letís pretend I donít care about mumbo jumbo and I just want to get all 6000w out of this thing.  How do i?
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Tim McCulloch

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Re: Generator suggestions
« Reply #52 on: July 01, 2019, 06:45:07 pm »

Well brad thatís exactly what I was trying to do and it seems Iíve been given lousy info earlier in this thread.

Letís pretend I donít care about mumbo jumbo and I just want to get all 6000w out of this thing.  How do i?

Full title boogie is 6000w, 7200w is peak load.  Engine performance is also a consideration, with less engine output at higher ambient temps and less output as elevation rises above sea level. MQ specs these at 60įF.  The details are in the owner's manual.

You can use a RacPacģ style device with an L14-30 flanged inlet and a pair of Edison 20 amp duplex outlets on each leg, each pair protected by a 20 amp circuit breaker.

Your amplifiers will be the biggest load on the generator and they present a dynamic load.  I don't know how you use your system (EDM will be much more taxing than an Eagles cover band) but averaged across a couple of seconds live sound current requirements are lower than you might think, but peaks are instantaneous and unforgiving.

Good luck.
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Scott Holtzman

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Re: Generator suggestions
« Reply #53 on: July 02, 2019, 05:09:16 am »

Well brad thatís exactly what I was trying to do and it seems Iíve been given lousy info earlier in this thread.

Letís pretend I donít care about mumbo jumbo and I just want to get all 6000w out of this thing.  How do i?

What bad advice did you get? You certainly can get 50amps at 120 (6000watts) out of the generator. 

What is your equipment mix?  Is there some 240 and some 120?  Do you have a load chart of what your are trying to connect?

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Stephen Swaffer

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Re: Generator suggestions
« Reply #54 on: July 02, 2019, 01:00:25 pm »

For years Iíve been renting 15-20kVa generators. Tow-behind type for outdoor concert series.  They use the 50amp California connectors to a spider box.  I know my rig works on 50amps. I suspect less, but I always try to get as much power allocated to me as possible.

That said/ Iíve been generator shopping for years.  Tow behind style would be dynamite but Iím at the level where Iím ready to drop $15k on a generator.

I want inverter of course.  And ideally Iíd like to get up to 50+ amps at 120v

Iíve seen a bunch of the smaller Home Depot type where you can link them for extra power.  Bonus points is that means 2 smaller ones for gigs that need them. Not often, but nice peace of mind.

Suggestions??

I suspect the "bad information" is a result of "Garbage In Garbge Out".  You asked for "50 amps at 120 volts".  That means different things to different people and in different contexts.  As Tim M said, you can get the 6000 watts out of the genny-but you can't run a 6000 watt/120 volt heater out of the genny.  Tim Hite pointed out you can get 30 amps at 240 volts-which also means you can get two times 30 amps at 120 volts. 30 +30 = 60, which is greater than 50.  If you don't need a 50 amp circuit anywhere.  Iy you have a single 120 volt load that requires more than 30 amps, then you are out of luck.

A sound system is not a single, steady load-it is a system of multiple, dynamic loads.  It's not hard-but it does take some effort to get "the maximum" out of a system.
« Last Edit: July 02, 2019, 01:07:17 pm by Stephen Swaffer »
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Steve Swaffer

Rob Spence

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Re: Generator suggestions
« Reply #55 on: July 02, 2019, 10:03:17 pm »

Hey Tim H, what is ďwet stackingĒ?
I am not familiar with that term.
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Chris Hindle

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Re: Generator suggestions
« Reply #56 on: July 02, 2019, 10:34:57 pm »

Hey Tim H, what is ďwet stackingĒ?
I am not familiar with that term.

From Wikipedia....
Wet stacking is a condition in diesel engines in which unburned fuel passes on into the exhaust system.[1] The word "stacking" comes from the term "stack" for exhaust pipe or chimney stack. The oily exhaust pipe is therefore a "wet stack".

This condition can have several causes. The most common cause is idling the engine for long intervals, which does not generate enough heat in the cylinder for a complete burn. "Idling" may be running at full rated operating speed, but with very little load applied. Another is excessive fueling. That may be caused by weak or leaky injectors, fuel settings turned up too high or overfueling for the given rpms. Cold weather running or other causes that prevent the engine from reaching proper operating temperature can cause a buildup of fuel due to incomplete burn that can result in 'wetstacking'. [

In diesel generators, it is usually because the diesel engine is running at only a small percentage of its rated output. For efficient combustion, a diesel engine should be run under at least 60 per cent of its rated power output.

It is detectable by the presence of a black ooze around the exhaust manifold, piping and turbocharger, if fitted. It can be mistaken for lubricating oil in some cases, but it consists of the "heavy ends" of the diesel fuel which do not burn when combustion temperature is too low. The heavier, more oily components of diesel fuel contain more stored energy than a comparable quantity of, say, gasoline, but diesel requires an adequate loading of the engine in order to keep combustion temperature high enough to make use of it. Often, one can hear a slight miss in the engine due to fuel buildup. When the engine is first placed under a load after long periods of idling and wetstacking, it may blow some black exhaust out as it burns that excess fuel off. Continuous black exhaust from the stack when under a constant load is also an indication that all the fuel is not being burned.
.................................
Over the years I've heard truckers talking about it, but never dove in for the explanation. I just figured incomplete combustion, but thought it was an injector problem. Not engine loading.
Chris.
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Dave Guilford

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Re: Generator suggestions
« Reply #57 on: July 02, 2019, 11:32:33 pm »

So it seems like getting all 6000w out of this will require something like this:

https://atielectrical.com/product/6503gu-cep-spider-box-input-30a-125250v/?gclid=Cj0KCQjwgezoBRDNARIsAGzEfe73kmUBZXI_JifHi2qThB_YhMEptjKylzS54uAwxQiwAq2H_ca2R8AaApVxEALw_wcB

BUT it would be broken out to 3 or more circuits, because this is only 40a (2x 20a). 

Yes?

Because 3 would allow up to 60amps, but of course our bottleneck is the 6000w produced.

Please let me know if Iím missing something.
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Scott Holtzman

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Re: Generator suggestions
« Reply #58 on: July 02, 2019, 11:33:39 pm »

I suspect the "bad information" is a result of "Garbage In Garbge Out".  You asked for "50 amps at 120 volts".  That means different things to different people and in different contexts.  As Tim M said, you can get the 6000 watts out of the genny-but you can't run a 6000 watt/120 volt heater out of the genny.  Tim Hite pointed out you can get 30 amps at 240 volts-which also means you can get two times 30 amps at 120 volts. 30 +30 = 60, which is greater than 50.  If you don't need a 50 amp circuit anywhere.  Iy you have a single 120 volt load that requires more than 30 amps, then you are out of luck.

A sound system is not a single, steady load-it is a system of multiple, dynamic loads.  It's not hard-but it does take some effort to get "the maximum" out of a system.

I have to admit I made the assumption the max load at 120v would be 20amps per load and easy to distribute across the two legs.  A single 120v 60 amp device did not cross my mind.

I also figured that if the device needed that much current you would use the 240v option since you can have a mixed bag in the distro of 240 and 120. 

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Scott AKA "Skyking" Holtzman
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Russell Ault

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Re: Generator suggestions
« Reply #59 on: July 03, 2019, 12:59:40 am »

So it seems like getting all 6000w out of this will require something like this:

https://atielectrical.com/product/6503gu-cep-spider-box-input-30a-125250v/?gclid=Cj0KCQjwgezoBRDNARIsAGzEfe73kmUBZXI_JifHi2qThB_YhMEptjKylzS54uAwxQiwAq2H_ca2R8AaApVxEALw_wcB

BUT it would be broken out to 3 or more circuits, because this is only 40a (2x 20a). 

Yes?

Because 3 would allow up to 60amps, but of course our bottleneck is the 6000w produced.

Please let me know if Iím missing something.

Close. You'd need one with at least 4 circuits. You can only pull up to 30 amps off of each leg, so you'll need at least two circuits on each leg to get the maximum power out of the generator. Remember, a split-phase generator is not a single 60 A 120 V source, but really two separate 30 A 120 V sources. Same total power, but it needs to be balanced properly between the legs.

-Russ

-Russ
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Re: Generator suggestions
¬ę Reply #59 on: July 03, 2019, 12:59:40 am ¬Ľ


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