|Quote, originally posted by IR SS3L3 Air Compressor »|
Ingersoll Rand Electric Stationary Air Compressor
3 HP, 10.3 CFM At 135 PSI, 230 Volt, Model# SS3L3
|Quote, originally posted by Review of IR SS3L3 Compressor »|
This is the first air compressor that I have ever owned, so it was a learning experience from the start.
It is recommended that you purchase the IR SS3L3 startup kit as the compressor is delivered to you without any oil in it. In some cases the warranty is not valid unless you have purchased the startup kit.
One thing I immediately noticed was that the pressure switch was flimsy. When I plugged in the compressor to test it out, I found that the motor continued to run even as the gauge on the tank passed 130 psi. As it creeped closer to 135 psi (the limit printed on the tank), I pulled the plug. I ordered a new switch from Ingersoll Rand for ~ $35 and this fixed the problem. Perhaps I could have made a warranty claim, but it was easier to order the switch as there is an authorized IR dealer nearby and I had the switch within 2 days.
I ran the compressor off and on for several months without any major issues. I used it for several things... a little bit of die grinding, I rotated the tires on my car using the impact wrench and air ratchet, I used it to blow dust off my work bench and check the air in my tires on a routine basis. I bought the compressor because I have several project cars, and I would like to begin the serious work of restoring them. Recently, I have been looking at plans for a sandblasting cabinet, and I am starting to doubt that this compressor will stand up to the task of sand blasting for extended periods. Things I have learned about the compressor since its purchase that have led me to this conclusion:
1. This unit uses a 3 HP "split phase" motor, which can be run on a standard 30A 230V household outlet - it draws about 15A during continuous duty. (I swap between my compressor and my dryer on the only 230V outlet in my house). The motor does not output a true 3 HP at all times. At startup the motor may approach its 3 peak horsepower, but during normal operation it may only be outputting half that power, so in truth it is essentially a 1.5 HP motor. This borderline false advertising is similar to peak and RMS power ratings in audio amplifiers, though it is fairly standard operating procedure to rate motors in this fashion.
2. The motor runs at 3450 RPM. Though it is quieter than a direct drive unit like the 30 gallon compressors sold at most hardware stores, 3450 RPM is still quite fast. With the pulley ratios, the compressor crank spins at 1200 RPM. Heavier duty systems might have the AC motor running at 1200-1750 RPM with the compressor running at ~700 RPM or less, resulting in a much quieter setup. If I could do it over, I would consider a slower, beefier unit with a true power rating that runs at a slower, more quiet speed.
3. There is apparently no available rebuild kit for the compressor itself, according to the local IR dealer, though they do sell gaskets and the oiling kit. It is a very simple design, consisting of essentially three parts; a cylinder head, cylinder block, and crankcase. It is a two cylinder, single stage compressor. The "valves" in the head are what I believe are called "reed valves", which are simply spring loaded "fingers" that cover holes in the cylinder head, and they move with the blowing/sucking of air as the pistons move in the cylinders (no mechanical actuation of the valves). The pistons are aluminum, and though I measured, I don't remember the diameter... something on the order of 60 mm. The rods are also aluminum, and there are no rod bearings. The crankshaft is cast iron machined at the journals, and the aluminum rods rotate on the crank without any rod bearings. The crankcase does not have a removeable oil pan, and the cylinder block bolts to the crankcase. I was somewhat disappointed to discover the absence of rod bearings and the use of aluminum rods.
4. The compressor can run fairly hot, especially when pressurizing the tank from zero pressure. I would like to add an intercooler in line to the tank as the compressed air is quite hot, and I think the compressor itself could use some more cooling. I bought some copper to fab up a larger heat sink for the compressor housing, though I haven't made it yet. I think this will make the unit run much cooler, and therefore extend its life. The flywheel on the compressor is designed to move air over the unit, but I still think the design needs improvement.
5. There is a flimsy drain valve in the bottom of the tank that is difficult to access. I have not yet installed a regulator and filter in the system, and I haven't checked how much condensation has collected in the tank. I would like to replace this drain valve, if possible, though I have been putting this off simply because I don't want to lay down on the floor and fiddle with it.
6. I have made several trips to the hardware store to find the correct fittings to get the unit running properly, though most fittings were readily available. It seems to me that a lot of the fittings on the system are kind of cheap, though I am used to the Swagelok fittings that I use at work, which are expensive and well worth the price. Copper tubing is used to route compressed air from the compressor to the tank, and I think some improvements could be made there, as well.
IR sells the SS5L5, which uses the same 60 gallon tank, but a 5 HP split phase 3450 RPM motor running a different two piston single stage compressor. For someone considering more power, this unit is still quite affordable, but it will still have some of the drawbacks of this system. It turns out that 5 HP is about the most one can get out of a 30A single phase 230V household circuit without flipping breakers.
My biggest complaints are the use of the split phase motor, the relatively cheap design of the compressor (aluminum rods and lack of rod bearings), the flimsy pressure switch, and the cheap fittings used all over the machine. I will continue to use this unit for some time, but I am already considering either building my own low RPM, true 4-5 HP air compressor from various parts suppliers, or just purchasing a new one from a company like Eaton Compressor. Ingersoll Rand makes the Type 30 series which is a step above the SS series, and I have considered these units as well, but I would almost feel safer building the unit on my own so that I know exactly what is going into it.
For someone that needs something better than the cheap 30 gallon direct drive units sold at most hardware stores, this unit is more than adequate. However, if you are considering something for medium-heavy duty, you might want to consider something with a little more quality, and therefore more cost. Like houses, I think good advice for someone looking to buy an air compressor is "buy the most you can afford". I for one like the idea of a compressor running at a quiet 750 RPM at a mere 73 dBa, as opposed to my high revving 1200 RPM SS3L3.
And as a final note, I will say that IR has excellent customer support. With authorized IR dealers all over the country, getting parts (like gaskets, pressure switches, and oiling kits) is pretty painless.
|Quote, originally posted by cnbrown »|
|Duty cycles are only rated at the machine fully cranked(heat setting at max). Although I think 220v machines are the answer(do NOT buy a 110v tig), a "big" 110v mig is an excellent beginner friendly machine that will be capable of quite a bit(especially automotive). |