Air Compressor Help

A power strip has a 15 amp circuit breaker because 15 is maximum current that the standard NEMA 15 type plug can provide. If air compressor demands more than 15 amps, then its plug must be different; cannot connect to a standard 15 amp wall receptacle. If air compressor has a standard NEMA 15 plug, then a power strip with 15 amp circuit breaker is sufficient.

Meanwhile, a power strip with surge protector components is not desirable; a waste of money. That grossly expensive power strip may also create other problems:

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Use a basic power strip without surge protector comp> Blink blink..surge protector strip....you are running an AIR COMPRESSOR

Reply to
w_tom
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No breaker box for the shop?

Those protector strips tend to use the least expensive breakers possible, and they generally run hot in the first place. Secondly when running a breaker near or at the trip amperage, they age poorly and start tripping at lower and lower amp ratings.

Gunner

"If I'm going to reach out to the the Democrats then I need a third hand.There's no way I'm letting go of my wallet or my gun while they're around."

"Democrat. In the dictionary it's right after demobilize and right before demode` (out of fashion).

-Buddy Jordan 2001

Reply to
Gunner

I've had a (genuine) 4hp compressor with a 20 gallon tank for about 20 years. I used it to build two homes, an aircraft, and hundreds of smaller projects. I wanted something with a wee bit more capacity in CFM and tank size, so I got one of these

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's substantially quieter than the parallel twin it replaced. Comes with a regulator, tank and regulator pressure gauges, and two (crummy but satisfactory) ball valves. Quality ball-valve tank drain is far enough off the floor to be practical. Paper element intake filters. Oil-level sight gauge, and PCV fill port. Wire mesh belt guard is good if a bit cheesily mounted, but doesn't rattle so I won't beef up the mounts unless they prove to be a problem. On-off switch probably wouldn't stand up to daily use, but is easily replaced with something better if needed. Overall the package is actually pretty nice, especially since it was on sale for $300. Judging by the description of your needs, it should suit you as well.

Aside - this compressor does *not* use the V-twin pump frequently seen in the HF catalog for about $100. That one is physically about half as large again, even though the specs are similar.

Wayne

Reply to
wmbjk

I do not think that a 12.5A 220V motor can be honestly rated as 4HP.

i
Reply to
Ignoramus20860

Any power strip without a circuit breaker cannot be UL approved AND is a threat to human safety. If the breaker starts tripping at lower amps, then good - humans are not at risk.

Meanwhile an appliance that has a standard NEMA 15 plug must not draw

15 or more amps. If an air compressor does draw 15 or more amps, then compressor will (must) have a different plug that will not connect to the power strip.

A power strip must have a circuit breaker - no way around that so necessary safety device. If breaker is repeatedly tripping, then fix a human safety problem. Breaker on a power strip is necessary and is required by UL.

Reply to
w_tom

And I don't think one should make a judgement based on accepting the manufacturer's current rating but denying the hp rating (and presumably the cfm as well). So I just measured it for you with a Fluke 337. 53A inrush, 18.2A running about 30 seconds after cut-in. Now, how many horsepower do you believe it should be rated?

Wayne

Reply to
wmbjk

Hm, so, is it a 12 amp or a 18 amp motor???

I am VERY surprised about your reading and the data plate discrepancy. It does not make any sense to me right now.

i
Reply to
Ignoramus20860

I agree. Just on plain watts at 100% power factor, 220 * 12.5 = 2750 W / 745.7 = 3.7 Hp. But, due to losses in the motor (several hundred watts at rated load) plus the power factor, I'd suspect 2.5 - 3 at the most. My 2 Hp compressor-duty motor draws 11 A at 230 V and rated load, just for comparison.

Jon

Reply to
Jon Elson

That's 12.5 A no load, 23.5 A startup, which is a funny way to state it. Upon opening the product manual, it states the following: ============ Motor

240 V~ / 60 Hz / Single Phase / 4 HP Peak / 3 HP Working / 3,400 RPM / 9 Load Amps / Two Capacitor (Run & Start) ============ So it looks like a 3 hp, for what it's worth.

Pete Keillor

Reply to
Pete Keillor

In article , Ignoramus20860 wrote: :>

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:I do not think that a 12.5A 220V motor can be honestly rated as 4HP.

Look again. That's 12.5A with no load!!

Reply to
Robert Nichols

(snip) To the above thought, this is a new occurance. I actually used my cutters weeks ago

Have you considered that the compressor is worn, and is not giving you the rated output? If there is a lot of "leak by" on the piston, or if the internal valves are but sealling completely, it won't deliver the full amount of air. If it used to do the job,but no longer does, then I'd start by checking out the compressor. An easy check on the discharge valves is to see if the head is hotter than it would normally be. If it is, then part of the air didcharged from the piston is being sucked bach into the piston on the down stroke. As it air is aready heated by being compressed previously,it will get hotter still when compressed again..

Incidently, if the compressor is not delivering the rated output,it will draw less current and be less likely to overload the circuit breaker, but if it constantly restarts, it will cause a surge in current each time it starts and one of these may cause the surge protector to pop.

Reply to
Tom Miller

My 3 HP compressor motor is rated at 16 amps. It is a Baldor.

i
Reply to
Ignoramus20860

That explains a lot!

i
Reply to
Ignoramus20860

I'm guessing that it's a 12.5A motor no load, a 15A motor when it's driving a pump that's pushing air into an empty tank, and an 18A motor when it's near fully-loaded during its normal cycle (where I measured it) and running off quasi-sine wave inverters.

I told my meter and motor what you wrote, and they said OH WELL.

I've seen compressors in this cfm range rated anywhere from 3 to 5hp. Most accurate is probably 3.6, which some manufacturers round up. HP ratings tend to be more conservative on older, physically larger motors. Same with newer industrial motors. I could replace the current motor with one of those and it probably wouldn't result in any additional air output unless the pulley ratio was changed as well, which wouldn't be a good idea. The beefier motor might result in more longevity, but since a homeowner-grade motor served me well for the last 20, and might even serve its new owner for another 20, I'll leave longevity worries to the tool snobs. Regardless, when shopping for compressors, the exact horsepower isn't very important. Instead one should be evaluating the cfm per dollar compared to similar models in the same class, as well as all the usual stuff like quality versus application. I mention that last part since there's a tendency for these Usenet discussions to have an overabundance of recommendations to buy industrial-rated equipment, with anecdotes such as "I chose an Air Terminator 2000 because I have birds depending on me for shelter, so it was worth the extra cost". :-)

Wayne

Reply to
wmbjk

They said OH WELL to their own data plate.

Most accurate is to note that 3.6 determines energy consumption of the motr at the rated current, not energy output (ie, does not take losses into account).

I had a really bad experience with a "homeowner grade" "pancake" compressor prior to buying my vertical. That POS was unusable.

i
Reply to
Ignoramus22416

No, I've already told you that one example consumes 18A loaded.

If you go to any subdivision construction site, you'll see guys working $250 pancake compressors harder in a week than you will in a lifetime. Since they're not buying new compressors every week, obviously there are affordable pancake compressors that aren't crap. IMO, your bad experience with whatever you bought is a poor reason for you to recommend industrial compressors for home use. There's almost always something in between POS and heavy industrial, and that middle ground is generally where the best value is for the average home shop. I've sometimes spent far more time than is sensible shopping for, dragging home, and making use of old iron. I've also spent serious money on new equipment that's far better than I need. But I don't recommend either of those approaches to others unless there's a sign that they need industrial equipment, or are interested in over-buying. Instead of this smug "real" compressor stuff you've been writing, perhaps you could tell us about some of the "real" work you've done with yours. Specifically, you could describe some scenarios that you've run into in which required industrial quality, 60 gallons of air storage, and triple the output of a tool's consumption. That way readers can compare your experience with their anticipated use.

Wayne

Reply to
wmbjk

On your inverter.

Actually, my compressor is not heavy industrial. It is an "econoline" and lacks features such as pressure oil lubrication.

One example would be that I used an air hammer to demolish tile in our sunroom, which took half an hour of continuous hammering (I did keep track of time). The compressor kept up with that.

Another example involved sanding wood finish in the same sunroom, which involved several hours of continuous sanding with an air sander. Again, the compressor kept up with that.

I did smaller jobs with a small air grinder also, and was happy that the compressor could keep one running for minutes (and cound do it continuously, but I finished my grinding in minutes).

A pancake compressor that I had would make those jobs very miserable.

i
Reply to
Ignoramus22416

Oh please, it doesn't make that much difference, and even I measured it on grid power I'm guessing you'd find something wrong with that as well.

C'mon!

I'm happy that you're happy. But I suggested examples of uses where what you have is *required*. A compressor twice as large would also keep up with the uses you've described, and so could many smaller ones. And, since your pump can keep up with your tools, then all of your jobs could have been done just as well if the same pump was mounted on a 5 gallon tank. Therefore, nothing you've described argues for 60 gallons, or a pump three-times tool capacity as you've recommended. And since similar jobs just like yours are done thousands of times per day on lesser quality equipment, neither does anything you've written argue for industrial quality.

I count my use of air tools as heavier and more frequent than the average home shop. I just counted over 30 air tools (thank you hard-working Chinese). Yet I can't think of any situation where I used but one at a time, and only a couple of situations where I needed more than 20 gallons storage (car hoist, and minimizing restarts for small jobs). You seem to be a reasonable person, so I think you'll agree that there are plenty of homeowner compressors in the 10cfm class that can handle my work well, and for many years. So why *exactly* would you recommend a larger industrial compressor for home use?

About 40 years ago I had a diaphragm compressor that also would have been a poor match for your use. But unless I missed something, no one has recommended anything like either of those in this thread. Your pancake compressor has turned into a classic straw man.

Wayne

Reply to
wmbjk

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