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.
Upload one or more videos to your post. Photo filesizes should be less than 300K and Videos, less than 2MB. Formats allowed are gif, jpg, png, ogg, mp4, mov, and avi. Be sure to use filenames without spaces or special characters, and filetypes of 3 digits lower case.
We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]
Today's Featured Article - Listening to Your Tractor - by Curtis Von Fange. Years ago there was a TV show about a talking car. Unless you are from another planet, physically or otherwise, I don’t think our internal combustion buddies will talk and tell us their problems. But, on the other hand, there is a secret language that our mechanical companions readily do speak. It is an interesting form of communication that involves all the senses of the listener. In this series we are going to investigate and learn the basic rudimentary skills of understanding this lingo.
... [Read Article]
Latest Ad:
2022 John Deere 5045E, 4wd, front end loader and 3rd function with grapple. 120 hrs, 55k new, must sell
[More Ads]
All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy
TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.
