Generator Power Shedding?

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Is there a power-strip like device for use with portable generators that turns off outlets when other outlets are using a certain number of watts?
Like you'd want to turn off the refrigerator while the sump pump cycles, to keep the total watts under say 2000; but mostly the refrigerator stays on.
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Ron Hardin wrote:

You can easily build your own if you're handy with electrical modules. You won't have to build any circuit boards because the parts are available off the shelf. You can use a current sensor and relay module manufactured by Functional Devices, Inc which are sold at many HVAC supply houses like Johnstone Supply.
http://www.functionaldevices.com /
http://tinyurl.com/5fuhg8
http://www.johnstonesupply.com/corp/Default.aspx
TDD
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The Daring Dufas wrote:

Generator load management is a bit more complicated than that and simply dropping lower priority loads when higher priority ones come on won't work properly and could potentially damage items.
A proper load management setup needs a controller with some smarts, and monitoring connections to things like sump pump switches, thermostats, etc. so that it can tell when an item needs to run, even though it is not currently powered. This type of control just isn't practical on a small scale where the cost of the control would exceed the cost of a larger generator.
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Of course it is. It's nothing but a logic setup. a = on, x = off etc. Simple current monitoring or even clamps.
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yes but you do NOT want to turn off power to the fridge and then turn it back on a few seconds later... the compressor will not be able to re-start when the pressure is already built up in the system... it will cycle on overload for a few minutes until the pressure dies down. That is OK it won't BREAK anything right away but it does stress the overload switch and compressor and is not the best thing to do for long term.
Mark
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Mark wrote: ...

... So what's a 555 timer cost???
The general idea isn't difficult to implement w/ anybody who's got some Radio Shack-type skills and interest.
It's probably there are some moderately inexpensive devices readily available altho I've not done any looking. Undoubtedly there will be info on the alternate-energy and living-off-grid and generator groups...
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Mark wrote:

Have you ever heard of an anti short cycle timer. It's a little module available at the same HVAC supply house as the other parts. The things are very inexpensive and I install them on AC units all the time. It would be easy to add it to the setup. Do I have to design the darn thing now?
TDD
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Twayne wrote:

Nope, the end result of such simplicity will just be an intermittently overloaded generator, devices damaged by short cycling, floods because the sump pump didn't get enough run time, etc. Proper load management requires the smarts along with sensing to hold off providing power to item Y until item X has completed it's cycle.
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Pete C. wrote:

Christ! Just a simple anti short cycle timer in the mix would do the trick. No big complicated control setup needed. Ever heard of relay logic? Nothing complicated needed for the application.
TDD
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You apparently don't understand a logic chart; or you wouldn't say that. x & y are NOT equipment; they are states. And simple to work out.
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Twayne wrote:

Baloney. Get a list of the various loads, the wattage draw of each and starting surge where applicable, and then you try to work out your logic chart for this application to determine which loads can be allowed to come online in what combinations without overloading the generator.
Be sure to account for devices that present more than one level of load such as a refrigerator (cool vs. defrost) and devices that could be damaged by repeatedly cutting their operation short, such as those with cool down cycles. Be sure your current monitoring reacts fast enough to drop excess loads when a new load comes online with it's peak starting current, before you stall a regular generator, or put an inverter generator into overload protect shutdown.
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Welll, I'll tell ya what; I didn't say the less than educated would understand it. You would need a decent background to fully understand it, even though the implementation is rather straight forward and do-able by most anyone who can minimally read a schematic.
If I didn't have experience in the area, I would not have offered this up. This however is likely my last response to the likes of trolls like you; you're not worth the effort, time or ether. You obviously have no grasp of the actual requiremnts so should shut up or offer instances where you can be showh where you're wrong or right. Then at least you would learn something. Ignorance truly can be bliss.
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Twayne wrote:

Yes, your ignorance sure must be blissful. The two of you trolls have yet to give a single bit of factual data, nor have you addressed any of the detailed issues I've mentioned. You should stick to wiring holiday lights.
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Pete C. wrote:

Which two trolls are you referring to? I would be glad to describe the simple way I'd setup an automatic switch that the OP asked about. Just ask, politely and without derision.
TDD
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Pete C. wrote:

2,000 freaking watts! Geez! A very simple automatic switch can do the trick for the guy. A current sensor, a timer and a relay could make up a simple load control for the man's generator to drop the refrigerator when the sump pump kicks in. No micro-controller or fancy PLC needed. If it involved 10,000 to 150,000 watts or more, I could understand the need for more finesse. For a generator I can pick up with one hand, nope, nope, nope.
TDD
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The Daring Dufas wrote:

Bull.
With a generator as small as 2KW, the generator will probably stall before you can shed the new load, and even if it doesn't it will bog down badly causing low voltage and low frequency issues. If it's an inverter based unit like an EU2000i it will just go into protect mode and you will loose output until you manually stop and restart the generator.
You think it sounds simple, but you've clearly never done load management, nor have you thought through the details of the problem. With a generator that small, the OPs safest and simplest solution is to swap power cords around manually.
Relay logic as you noted in another post would be a bloody mess for this since you have to know the load of each of the controlled outputs and determine the allowable combinations that will not overload the generator.
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Pete C. wrote:

Good Lord, you're making it more complicated than it needs to be. I could do it quite simply with all off the shelf inexpensive timers and relays. I have had a smidgen of experience with little Cats and tiny little 16 cylinder EMD generators putting out a minuscule 4,160 volts and enough current to melt the proverbial crowbar. Don't over engineer the golly gosh darn thingy itty bitty generator, it's not an APU on the space shuttle. I guess all those 5 to 40kw generators I've installed and maintained for homes and business have left me with a substantial dearth of knowledge when it comes to electrical systems. Should I walk you through the simple steps that would address all your dire concerns for blowing up the itty bitty power plant? Of course, the simplest thing is as you say is to switch cords but if he's anything like all of us lazy humans who love to take advantage of existing technology for the sake of convenience, he wants something automatic.
TDD
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The Daring Dufas wrote:

Whoop-dee-doo, you still haven't covered the actual issues, particularly with the probability of an inverter based generator give the OPs mention of 2KW, and the fact that as soon as the new load came online the inverter would trip out on overload before your relay could shed other loads.
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Pete C. wrote:

What inverter based generator? The guy has a itty bitty generator sitting on top of an inverter? That's a heck of a silly thing to place a generator on top of. GEEZ!
TDD
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Why? For what valid reason?
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