Portable generators


Old 03-16-13, 11:56 AM
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Portable generators

Revised first post:

Portable generators
Most generators have a 30 amp outlet to connect to your home.
Why have a generator that's rated over 7200 watts? (240 volts times 30 amps =7200 watts ) The breaker on the generator is going to limit the output. I see people buying 8000 to 10,000 watt generators that have that same 30 amp twist lock.

My next thought was running a well pump that is a long distance from the house panel. The longer the wire, the more the voltage drops. I want to over size the wire going down to the well pump. The reason I mention this is at my parents house, the generator is behind the house and the well is in front. That long run surely doesn't help the pump starting up when the generator is connected.

I plan on putting a Sola power conditioning transformer to correct the voltage spikes and sinewave distortion. I will double check with Sola to make sure that, as per their web sight, that their transformers do in fact correct sinewave distortion. ( I got it for free ) The reason this worries me is now our homes are filled with electronics. There are invertor generators out there and they come with a huge price tag. They put out nice clean power that won't damage HDTVs and computers, or for me, my new boiler with electronic controls.

People ask me ( as an electrician ) which generator will run thier house. As if, all house have the same load or what each person wants on line when the power is out. My needs are simple. Heat and water. My boiler only draws a few amps and my well is only 1/2 hp. My fridge is almost new and not an older energy hog. I can run my microwave w/o issues, and the rest is just lights. Many homes have electric hot water heaters and electric stoves. That brings me back to my original point. That 30 amp outlet on the generator. Have people been misled into buying that big generator to run the water heater and the stove?

Last edited by ray2047; 03-17-13 at 12:21 AM.
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Old 03-16-13, 12:51 PM
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Wow......quite a mouthful

Limitations on twist locks. Not quite sure I'm following you.

I use tons of twist locks especially on my rental units. The hold up well and have never had any connection issues.

I run my house on either a Honda EM-5000 or 6500. Both are connected using the 4 pole 120/240 connection. Never a problem.
Old 03-16-13, 03:35 PM
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As far as your boiler electronics go, there is more to it than voltage and frequency regulation. A power conditioner is not going to smooth out a noisy sine wave.

This thread may be helpful: http://www.doityourself.com/forum/bo...tml?highlight=

I remember having some other links to someone who observed the sine waves on a few different generators. I found it very illustrative of what dirty power looks like on an oscilloscope. I don't recall what thread those were in.
Old 03-16-13, 10:26 PM
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Sorry for the long winded post and making it hard to follow. PJ Max, the thing I was pointing out as far as the twist lock connection is the fact that generators are limited to a 30 amp load by the circuit breaker on them. ( not the actual twist lock)

Drooplug, the power conditioning transformer helps with voltage variables and also wave distortion. How much, I'm not sure. I'll contact Sola because now you have me curious. I know generators can put out some ugly power fluctuations.

I'll try to repost this is a much simpler format so that others can grab the concept. sorry for the confusion I've created.

Mod Note: It's not confusion, it's the difficulty of understanding what you're saying and asking when everything is one long paragraph. Just re-post your original text with paragraphs, double spaced as I've done here, and one of us will remove the older one. Then you're likely to get more answers and better-focused ones!

Last edited by Nashkat1; 03-16-13 at 10:47 PM. Reason: Change formatting and add note
Old 03-17-13, 12:26 AM
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Thank you for the revised first post. I have added it to the beginning of this thread.
Old 03-17-13, 01:26 AM
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Thirty amperes at 240 volts is 7,200 watts and with the exception of water heaters, electric furnaces, electric kitchen ranges and the like is probably enough to get most people through an episode of urban camping while experiencing a utility power outage. It certainly won't be living the same as when grid-connected but it should make it possible to avoid the shelters and motels.

That said, any generator of over 7,200 watts (7.2 kilowatts) should indeed have a higher rated single point receptacle or else the output divided among more than just a single point receptacle. Each receptacle should have overcurrent protection equal to or less than the receptacle's maximum rating.

Sola makes several different kinds of "power conditioning" devices. The one I am most familiar with is the constant voltage output transformer. This device uses a ferroresonance circuit to change an incoming variable voltage to a constant output voltage. It works well for that purpose but it DOES consume a fair amount of power internally, maybe as high as 10% under some conditions, so I would keep that in mind as you plan your installation. If I remember correctly this unit also outputs a fairly weird waveform although still 60 Hz. that will change depending on the output load. I don't know how that weird waveform might affect the newer electronic devices, perhaps not at all.

For the well pump you need to know both the starting amperage and the running amperage to calculate voltage drop. Understand that running motors with small generators is problematic because of the starting amperage requirement and even when the generator can supply that starting amperage it may not be able to start the motor because the load is applied instantaneously and the generator will bog down before the governor has a chance to increase the engine power.

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