Air Conditioning & Larger Loads

I receive many emails from folks with 3 ton air conditioners that are told they need a 15kw or larger generator to run their AC and other stuff. I believe it is important to sell people what they need, and no more. Smaller generators are less expensive to buy, cheaper to maintain, and in many cases the smaller sets get better fuel economy.

I have a friend with a 5hp air compressor.  It will kick out a 30 amp breaker because it attempts to start with pressure against the piston (bad; but easily fixed). Others report starting and running a 5hp air compressor with the lowly 6/1 and a properly set up gen head. A friend in Australia uses his 6/1 for running an ARC welder, and he notes that his Honda gas generator that provides twice the KW rating struggles to run it, we must consider those flywheels and know they are a source of energy and storage.  We might note that the world is full of people that push the truth. It starts when your competitor starts lying about their products, and pretty soon, their sales are up and yours are down.

I first saw it in stereo amplifiers.  A few manufacturers started using peak power figures versus RMS power, and soon other vendors followed suit.  The public was totally confused, and many potential buyers have no clue about peak versus RMS power, and just how big a difference there is, they just buy what they think is the most for the money.

A prime example of this is electric appliances, Hardware store air compressors are advertised at peak Horse Power figures, Vacuum cleaners are advertised in the same way. In fact the Vacuum cleaner saleswoman[1] stoops even lower. I have seen a good many advertisements where the Amperage is used as a power figure, more amps, more suck! It really sucks that they get away with it.

As we know, there’s a lot of design work to get efficient impellers to create that suck, and we also know there are countless other factors. We know we could add a heating element to that vacuum cleaner and pull even more amps, but I doubt it would suck any more dirt off the floor.

Back to that air compressor, is it really a 5hp unit you have? Maybe the one the Lister 6/1 has been running so well is just like 99% of them, it’s called a 5hp, but that’s a peak power figure.. Peak HP is the Horse Power that occurs at the peak, if we look at the AC sine wave, we notice there is a moment when no work is done, (the zero cross over). The recognition of this leads to the RMS figure which is the attempt to give you a more meaningful figure.

I always tell people to put a ‘clamp on amp meter’ on their stuff to find out what it really takes to start a load, remember running takes far less than starting.

Many of my AE Motorhead friends are in the south, and I can tell you they would rather have a cool room in the heat of the day during a power outage than food! We up north have little appreciation for just how hot and miserable it can get. I remember visiting Atlanta Georgia, there was a popular shopping district all set up underground, one could go from building to building underground, just like Prairie dogs, and with darned good reason.

As of this writing, I realize I can no longer ignore Air Conditioning loads, and folk’s pleadings to help size generator sets to allow them to run the stuff. At times, answering all my email is impossible, so putting answers on the CD, and posting at is the more reasonable solution.

I am aware that lots of stuff is designed to sell, and far less things are designed to live with. Small refrigerators drive me crazy, but till I started corresponding with Nomad Joatman, I didn’t have a clue as to what was really going on in some of my observations. For me to attempt to learn what this man already knows, and write about it, would be a little like trying to catch up to Jeff Maier in Electrical Engineering, and use of Biofuels.. I’d have to be smoking rope to think that would happen.

Sharing information is key, those who take the time to inform themselves will do well, I get a good many emails saying.. “I wish I would have read that before I bought. Can’t we all say that?

It is time our community had a little information about load management, it will make all the difference, I know this and have written about it, but I am NOT an AC guy or an HVAC guy either, these certified installers and repair people size and install all kinds of stuff, some feel the smallest detail is a trade secret, and they’re likely to be out of work if they tell you anything helpful, others are disgusted with sales types, that would sell their own father[2] twice what he needs because the commission check is bigger..

The Nomad lives in a land Yacht of his own making, it is a rolling lab of sorts, and on top of being certified in two important disciplines, he has the incentive to come up with efficient designs for himself. It means it works better with less power, and burns less fuel, that’s exactly what we want on the grid or off the gird, energy won’t be getting cheaper anytime soon.

I have the pleasure of having friends and associates from around the world, I learn that Mamad in Iran is busy with his customers teaching load management and providing solutions that allow customers to continue running their existing generators even though their business (and loads) has grown considerably.

We need to spread the word, it’s good to use less energy, and best to run a smaller generator when you can..

Tod Bjorkman is one of the greatest information gatherers I ever met. Give this guy a problem, and the first thing he’d do is gather a pile of reference material on the subject taller than a building, then he’d organize it according to relevance and digest the material. Tod would distill the material and produce answers and solutions as if they came from God!

I need to stay focused on information, there are too many distractions in life, selling is one of them.. As I write this, I am excited about the new generator; it is simple, more efficient, longer living, and starts and runs loads like nothing else I’ve seen. DIYers need access to it, there is only so much you can do in a day, Utterpower must stay on information,  there is a transition underway here. it is all about delivering a higher return on investment.

I’d like to introduce you to Nomad Joatman, certified HVAC and AC technician.

[1] We must not assume it’s a man doing the selling.
[2] Another attempt to degenderize this article, Hillary will appreciate my efforts here.

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