Air compressor hp

[junkyardjeff]

I have two blown up 5 hp 60 gallon compressors that parts are not available so time for a new one,noticed most of the new 60 gallon compressors only have a 3.7 hp motor and wondering if there is a noticeable difference.

 

[Moosefire]

Not sure what has blown up but any chance you can fabricate mounts, or something for what I assume is a blown motor?

Sent from my SM-N960U using Tapatalk

 

[junkyardjeff]

Pumps are toast and both are over 30 years old and I need a compressor now and do not want to wait to get the parts and would be nice to have something new for a change.

 

[u3b3rg33k]

tank size is less meaningful than the CFM rating (which is often a lie). if you know what CFM you need, find a compressor that claims to do that, and then make sure it's possible with the motor rating.

you'll typically see 3-4cfm/hp on single stage, 5-6cfm/hp on dual stage. if they claim more, it's marketing nonsense.

for casual use, I like the CAT quiet compressors. my 1HP/8gal claims 3CFM @90 psi, 4CFM @ 40PSI. i think that's a bit optimistic but it holds pressure while running the plasma cutter so it's good enough. equally important I can run it without hating it. the torch is louder than the compressor by far.

For real work I won't touch a reciprocating compressor without a full pressure oil pump.

 

[marinusdees]

Pumps are toast and both are over 30 years old and I need a compressor now and do not want to wait to get the parts and would be nice to have something new for a change.

If you need a compressor NOW, go buy one and don't post for advice.

 

[Citation]

I have two blown up 5 hp 60 gallon compressors that parts are not available so time for a new one,noticed most of the new 60 gallon compressors only have a 3.7 hp motor and wondering if there is a noticeable difference.

Depending on the age of the compressors you might have one of the "5" hp compressors that drew the same 15A @ 230V that you see today in a "3" hp compressor. Basically for a while the advertised power ratings were bogus. Even now it's not clear and you might notice that the rated power on the motor plate is "spc" or "special" meaning the mfr doesn't want to state a power rating, presumably because when tested using what ever test method the motor wouldn't deliver the compressor's advertised power.

Anyway, if you just blew the pump you might look at getting a HF 3 or 5 hp, single stage pump. They are low cost and seem to work well, especially for the money. You can also use a 20% off coupon when buying.

As for new, I think you need to suggest a budget first. I'm a big fan of Champion compressors but I have almost no data to suggest they are better than so many other options. I would say that ~$500 gets you the current crop of "3hp", 60 gallon compressors that will deliver around 10-12 CFM @90 psi. ~$1000 is where 80 gallon models that are 13+ CFM start. It seems like the more industrial stuff starts at over $2k. Do consider your needs. A $1400 and $3k compressor might both advertise the same 80 gallon tank and CFM but the $3k compressor is almost certainly going to have a magnetic starter, perhaps an auto drain, more reliable valves and valves that can be serviced without pulling the head etc. The cheap compressor might directly switch the motor with the pressure switch vs using a more durable starter. However, like Ford F-150 vs F-350, that extra capability might not matter if the loads you haul aren't that big or heavy.

 

[junkyardjeff]

There is around a 200 dollar jump in price from the 3.7 to the 5 when the compressors look the same,the electric motor can not be that much different in price or are there other changes to get the price up that much.

 

[Citation]

There is around a 200 dollar jump in price from the 3.7 to the 5 when the compressors look the same,the electric motor can not be that much different in price or are there other changes to get the price up that much.

Do you have any specific examples? Typically what I see is the $500, 3hp models have smaller 2 cylinder pumps. In some cases they are nearly identical to the pumps used on the 120V belt drive models. However, the compressors that jump up to around 5hp (call it 19+ amp motors) will have physically larger pumps in addition to the larger motor. Also, what I typically see is the "5hp" models have an 80 gallon tank. This site shows about a $100 jump between a replacement 60 and 80 gallon tank. I would guess that you are looking at perhaps a $50 jump when priced as part of a compressor.
https://www.compressorworld.com/air-tanks/vertical-with-top-plate

 

[joshmodelskidoo]

I believe Menards has a 60 gallon masterforce for $430 right now. I would probably go that route myself. I just picked up a sanborn 60 gallon from them about a month ago and I believe they are replacing sanborn with masterforce but they look to be the same compressor but with a different sticker. Harbor freight carries pumps but I think a new compressor is probably the way to go because of the hit and miss in quality at hf and possible rust in your tank

 

[seber]

Look at the motors on the burned out compressors. One hp is 746 watts. There is an efficiency loss of ten to twenty percent. That will tell you what the actual power is. Do the same for the compressor you are looking at buying. There is some variability in output but it pales in comparison to the lies used in motor power. One man I worked with had a "6 hp" compressor that ran on a standard 115vac outlet. 15 amps times 115 volts is 1725 watts. Counting efficiency loss that converts to less than two hp.

 

[Monza Harry]

I use the 5 Amps @ 240V as (/)1 HP. (62.1% efficiency) 10 A @ 120/HP as a way to check the outlandish claims on the marketing sticker. 1 HP. is the ability to move 33,000 pounds 1 ft. in 1 min. (or 1 pound 33,000 ft. in 1 min. or any mix of the same) So torque in Ft/# times 2 Pi times RPM divided by 33,000 will equal real HP. Those "Bogus" numbers may not actually be bogus as with an air compressor if that 1/2 HP. motor is run continuously and the air is used at 10% then it is capable of making 5HP. of air, albeit at 10% cycle duty, but wait the thieving B@#$%^&ds put a motor that will not run continuously. One other thing to consider is the motors "Cycle Duty", "Continuous" isn't the highest rating, "Cycle Duty" is, that is defined as start run shut off and then restart shortly thereafter (IDK what the time interval used for run or stop for that rating, Sorry) I wonder if the bogus rating is achieved with stalled torque (0 HP) and then the overspeed when the stalling lock is removed (also 0 HP). I hope this gives you some more clarity on your future plans. Harry

 

[matt_i]

Another way to easily estimate is to calculate: Volts * Amps = Power / 750 and that's going to be your actual HP within the 10-20% efficiency.

Volts is going to be 120 or 240vac, and the amperage is from the motor's nameplate, it could be listed as FLA or Full Load Amps.

 

[junkyardjeff]

Did some looking today and those 60 gallon with the 3.7 hp motors put out more CFM then my Campbell Hausfeld 60 gallon 5 hp compressor,could not find any specs on the 5 hp Sanborn that just quit but have my eye on a Ingersol Rand 5 hp 60 gallon that I might get monday. I have found used compressors but if I get another new one it could be the last one I buy,I do not want to spend the money for new but I do not want to have to replace them every year and got over 30 years out of the C/H compressor.

 

[Citation]

Do you actually need a 60 gallon, 10+ cfm compressor? That's a whole different category vs what I was suggesting.

Edit: sorry, I was confusing threads. Ignore that question.

 

[junkyardjeff]

When I get doing body work I need all the air I can get,I also use air grinders too and really could use a 80 gallon but 60 will do just fine. I would rather have the capacity and not need it then to need it and not have it.

 

[Citation]

When I get doing body work I need all the air I can get,I also use air grinders too and really could use a 80 gallon but 60 will do just fine. I would rather have the capacity and not need it then to need it and not have it.

Sorry, I confused commission threads. Never mind my question.

 

[junkyardjeff]

I have decided to get the Ingersol Rand compressor early next week and I hope its the last I will have to buy unless I need to go larger.

 

[Downwindtracker 2]

A lot of these motors are Chinese. Let's just say 20 amp Chinese is a little different than a 20amp Baldor.

 

[marinusdees]

A lot of these motors are Chinese. Let's just say 20 amp Chinese is a little different than a 20amp Baldor.

I have it on good authority that Chinese varnish smells different than US varnish when the motor burns up. If you need reference source, I can provide it.