Which will be cheaper

My electric bill keeps climbing. I have a 222v 3 hp compressor I run a lot. Now will it be cheaper if I run a compressor that has a 5 hp gas engine. Gas now is around 4.40 here. Any thoughts? Stan

Electric by far cheaper.

Don't think so---plus an electric motor will last far longer than a gas engine with virtually no maintenance.

Ben

Electric will be cheaper. I would check to make sure your compressor belt is tight or go to a bigger pulley on your motor that would spin your compressor faster and not run as long.

I think at 12 cents the electric will run for 1/3. And be a lot quieter.

I heard years ago that a 100 ft extension cord pulls the same watts as a 60W bulb. I run lots of cords and I kill all power to the shop when I walk out.( can t hurt)

Can you get by with less pressure?

It's cheaper to run an electric motor. Also the higher the voltage the more efficient; 220 is better than 110 and 440 would be the top dog (not that anyone has their house wired with 440).

How much are you paying per kilowatt-hour?

For me, my last electric bill was about $100 bucks, or roughly $3 bucks a day to run lights, air conditioner, tv, fridge, freezer...etc.

If I wanted to do that with gasoline power for the same cost I would be limited to burning a gallon a day!

"Also the higher the voltage the more efficient; 220 is better than 110 and 440 would be the top dog (not that anyone has their house wired with 440). "

I'm gonna call you out on that one!

ASSUMING wiring is adequate in all scenarios that is simply WRONG.

Running a higher voltage WILL allow for smaller/lower cost WIRING, though, but NOT affect the cost of power for a given HP load on adequate wiring is in place.

I don't think the cost is from your compressor or arc welder, more likely electric heater or air conditioner it the house.

electric
I have a larger compressor and it runs constantly in the warmer seasons when I'm in the shop every day.
Difference in the power bill is surprisingly small.
Switching every bulb here to the squiggly ones, and now to LED cuz they are finally dropping in price....power bill went down more than the compressor makes it go up.
lol...free compressor use

Of course electric bills are climbing. Diesel and natural gas cost more than coal, and there are no new nuclear or hydro generating plants being built.

NO, cost per kwh does not change....the caveat in your statement is "adequate wiring".

Real world wires have resistance and you will lose a small but measurable amount. The voltage drop as a percentage of the total becomes smaller and smaller as the voltage goes up.

Let's look at 100 feet of 10 AWG wire carrying 5 amps. At 110 volts I lose 1 volt at the end for .91% voltage loss. At 440 I still lose 1 volt but my percent loss drops to .23%. This is with a 10 AWG copper wire at .0009989 Ohm/foot.

It just depends on what you mean by adequate wiring. To cut the loss in half in this example you could go to 7 AWG wire. At some point it gets ridiculous.

Pulling the same load like a water pump, the 110 motor with higher amps will run hotter. Heat doesn't pump water. So it will run cheaper on 220. Magnetic field comes from the atoms of the wires excited by the voltage.

(quoted from post at 18:46:34 07/21/15) My electric bill keeps climbing. I have a 222v 3 hp compressor I run a lot. Now will it be cheaper if I run a compressor that has a 5 hp gas engine. Gas now is around 4.40 here. Any thoughts? Stan

Click to expand...

I think you need to look for another reason as to why your electric bill is going up. My 230 volt air compressor with 60 gallon tank can run for days on end and not effect the electric bill enough to notice. Same for my stick welder and mig welder.

Seems like the only thing that effects our electric bill noticeably is the house AC.

Just remember who said he would burry the coal industry!

Bob,
You are 100% correct about that. I constantly hear people saying its cheaper to run your stuff at a higher voltage. As you stated, this only helps by allowing the use of smaller feeds / conduits / cables that powers your componets. Unless your in a factory and have long runs of cables the only thing your gaining is better motor start up and longevity of the electrical componets, less current means less heat.

This is more in reply to Haymaker. P=IxE is the same if the number of one doubles while the other gets cut in half in the same formula. Same wattage results.

Is gasoline really $4.40 where you are? Around w.c. Ohio it's around $2.40, been dropping.

Once I got all mad about all my friends beadblasting parts for hours in my cabinet so I calculated the actual cost and you could run the compressor aLL afternoon for about 50 cents.

(quoted from post at 17:47:31 07/22/15) This is more in reply to Haymaker. P=IxE is the same if the number of one doubles while the other gets cut in half in the same formula. Same wattage results.

Click to expand...

Algebra...getting pretty in depth here!!!! Regardless what numbers you plug in from the motor (amps or volts) it equals the same amounts of voltampres or watts. And since they bill us for the amount of kilowatts we use it does not really make a difference if the motor is 115vac or 230vac...

The only savings are on a large motor in a factory or of sorts (simular situations). Where you will only need to supply a 50 amp service instaed of a 100 amp service.

(quoted from post at 22:42:05 07/21/15) I heard years ago that a 100 ft extension cord pulls the same watts as a 60W bulb. I run lots of cords and I kill all power to the shop when I walk out.( can t hurt)

Click to expand...

Ain't true.

746 Watts per hp. Watts are volts x amps x cosine of the phase angle between them....aka power factor. My 2 hp electric motor has cap start and cap run. Start ensures a fast start under load....course if the pressure unloader valve on your compressor is functioning, there won't be any load on the motor at startup.

Run cap run keeps the amps and volts aligned within 80% (pf = 0.8) to keep the power company happy.....they get paid via a Watt meter, not by measuring volts and amps. Just for a number, if you were running your electric induction motor and it had no power factor correction, it could appear as a pure inductor which would have the cosine at 90 degrees and the Cos. of 90 is zero. Power company would get zero dollars for the power they supplied you. Not gonna happen.

The losses are less in an electric motor as compared to an internal combustion engine.

I pay 12c per kW hour. So if I have a 3 hp electric motor running 3 x 746 Watts per hp, at a power factor of 1 (voltage and current in phase like across a resistor...for a nice round number in this calculation) in an hour I would have burned (3 x 746)/ 1000 = 2.23 kW. For me that would be 2.23 x 12 cents.

Basic engines sloppy rule of thumb is 10% of the hp actually used in gallons per hour of fuel consumed. So a 5 hp engine would be burning $4.40 x .5 gal per hour = $2.20 and I think it would take a 5 hp to equal a 3 hp electric motor (due to efficiencies of scale) in work function due to the poor engine efficiency of the internal combustion engine.

I think BD ran the numbers the other day and if you got 50% on an engine you were in heaven; his numbers were more in the 30ish percent range. On an electric motor 90 % area is more the norm. Where is all that loss? Put your hand on your compressor motor the next time it's been running. Just warm to the touch. Now go and put your hand anywhere on your internal combustion engine.............er better not it will give you a bad burn. Last time I measured my air cooled lawn mower the exhaust was about 550 F, crankcase 165 to 200+ in different areas, valve area around 180.......that's where.

Plus the elect starts every time. The gas????????

Anything you can do to reduce your standby air pressure will save you money.

Compressed air is an inefficient and expensive way to power hand tools. Have you looked into phasing out air tools and replacing them with corded electric tools or battery powered cordless tools.

I agree with ss55. I got rid of most of my pneumatic tools and went with electric. Pneumatic tools are about as efficient as a steam engine. You are paying to run a 5 hp compressor, when an electric sander or grinder will use a fraction of the electricity.

The answer to your question is no, electric is more cost effective. If it were cheaper to make electricity with a gas generator, everyone would get off the grid and make their own electricity.

(quoted from post at 06:39:18 07/22/15) Of course electric bills are climbing. Diesel and natural gas cost more than coal

Click to expand...

Fuel cost of NG has dropped precipitously with new supplies tapped, the post-burn cleaning of coal is getting even more expensive.

and there are no new nuclear or hydro generating plants being built.

Click to expand...

There are thousands of people working in Georgia right now who will argue this point...