I was in Harbor Freight in Columbus, OH the other day and saw they are having a huge sale on November 28 -- the day after Thanksgiving. This is chain-wide and you can access all their locations by going to harborfreight.com
I am sure they will have some GREAT deals!
I went to my first HF yesterday. They had a marvelous 2hp motor for my table saw that only drew 15a and weighed about the same as most 1hp motors. How on earth do they do that, and for only $60!? I can't wait to install it.
Most of the rest of the stuff there was junk. I would have been disappointed, except for the motor.
I think you answered your question with the sentence before it.
I can't wait to install
A 2hp Motor that draws 15A on 110V must be one where the electrical power consumption is given, not (al more usual) the mechanical power.
15 Amps is about right for 2 hp at 120 volts and 80% efficiency. Nothing unusual if its running current.
Great deals on JUNK, just kidding some of there stuff is ok if your like me just a hacker, what I dont like is the idea that everything and it's not only Harbor it's Home depot Menards Lowes etc that most think's today is either made in China or Tiwan Korea etc. Do we make anything here in the good old USA any more
You might want to wait. A 1.5 HP induction motor will draw about 19-22 amps on
115. Sounds like yours _is_ a 1HP. Along the lines of "3/4 HP" China bench grinders that draw less than an amp.GTO(John)
um i think thats called a flea market!!!!! same crap BUT you pay sales tax. lol. :-] skeez
Small world. I'm actually sitting here in Zhongshan, China as I'm typing this. I'm at a factory where about 3000 workers are enjoying the jobs that used to be in the USA. They used to be minimum wage jobs in the USA that became too expensive.
Remove the 'remove' in my address to e:mail me.
Toilet paper
Utility knives.
BALONEY! 1HP is 745.7 watts. That's a little over SIX amps at 120V.
2HP, 1491.4 watts, equates to a current draw of approximately 12.42 A at 120V. 15A draw, at 120v, *WILL* give 2HP at the motor shaft, if the motor has an efficiency factor of roughly 83%.With motors in that size range typically having efficiencies of 80-85%, there is *nothing* unreasonable about the rating. It looks like an -honest- one.
Unlike my little shop-vac, which claims "3.0 HP (peak)", and for which the 'plate' reads 7.25A, 115VAC. To deliver 3HP at that voltage/current, the motor would have to be 268.3% efficient. *snort*
Anyway, for rough figuring, electrical equates for 1HP, at typical (80-85%) motor efficiencies:
7-1/2A @ 120V 3-3/4A @ 240V 4-1/3A @ 208V (2-phases from a 3-phase 240V distribution)
I would like to see the motors you descibe! Graingers lists a high efficiancy 1-1/2 HP motor that draws 14 amps @ 120 volt, 7 amps @ 240 volt. Standard efficiancy motors run higher amps yet. A 2 HP high efficiancy motor is shown to run about 20 amps @ 240 volts. Again standard efficiancy motors are higher amps yet. The most you can run on a 20 amp, 120 volt circuit is a 1-1/2 HP motor. @ HP goes to 240 volt. I have always used 1 HP per 10 amps for 120 volt, 5 amps per HP for 240 volt, it my run SLIGHTLY less with higher horsepower motors, but you will be safe. Greg
I'm well aware of the math, and you're right about that. The problem is that your "real-world" figures are what's BALONEY! I've never seen any induction motor on this planet with from a reputable maker with a usable service rating that comes anywhere close to those figures. What you're likely to find for actual induction motors:
1/3HP motors would draw around 4-6A, 1/2HP from 7-9, 1HP in the 13-16 range, and a 1.5HP motor 18-22. All of this is pretty close for both split-phase and cap start. I don't have cap run figures on hand.Go and look at products from a real motor company.
GTO(John)
I'm not arguing your figures, because I have an old 1/4 hp that say 5.4 amps, but 16a at 120v for 1 horsepower means an efficiency of 39 percent. Is this true of even modern motors?
My Baldor 1/4 hp (about 1 year old) rated at 2.8 amps which comes to 56 percent efficiency and I have a 1 hp (about 30 years old) rated at 12.2 amps which is 51 percent. All of this seem rather poor c>
Like I said in my post, 1HP would be in the 13-16 range. The 16, of course, is way up there and not seen much any more, and your12.2 is pretty close to 13. I can just mention general guidelines, since I haven't looked at every motor or spec sheet out there. The 1HP motors I have on hand are 14.7 or something like that.
The 1/4 HP at 2.8A really suprises me for an induction motor, although I don't doubt the rating if it's from Baldor.
GTO(John)
Does Baldour count as a 'reputable' manufacturer, and a 'real' motor company?
How about one of their units, rated for continuous use, i.e., 100% duty cycle at full load?
it's 120/240 c1.5HP at 120V, 2.0 HP at 240V
12.8 A at 120, 8.6 A at 240.At 120V, "theoretical" for 1.5 HP is a tad over 9 A, figuring 83% efficiency takes it to about 11-1/4.
It's gonna be 19-22A at 120V, you say?
Seems like _this_ 'real world motor', from a 'reputable manufacturer', is a lot closer to my numbers than yours.
Hell, I've got engineering reference handbooks (from 'inconsequential' technical publishers like McGraw-Hill) from the *1920s* that document "average" efficiencies for 2HP 220V motors at 82% at 1/2 load to 84% at full load.
At 10HP, they're 85% efficient across the range.
At 100HP, one is looking at 91% efficiency at 1/2 load, and 92+% at full load.
I will note that starting current, _for_full_load_torque_, is stated to be
2.7 - 3 times the full-load current.Your claimed 19A @ 120V giving 1.5 HP equates to a _maximum_ 'efficiency' of 49.02% The 22A 'high-side' is even worse -- 42.34%.
This implies that "modern" motors are significantly less than 2/3 as efficient as the 'typical' motor built in the 1920s.
Somehow I *really* doubt that that is true.
As one gets down into the fractional HP range, overall efficiencies do tend to go down significantly. I've got a FASCO INDUSTRIES 0.1 HP (honest measure, I've had it on a dynamo), that draws 1.08A at full load. So says the plate -- I measured 1.05 A, using a _non-calibrated_ meter. (a 10% error wouldn't surprise me.)
At a straight scale-up to 1.5 HP, that'd be about a 15.5A draw.
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