Air Compressor Motor Problems
I have a Ingersoll Rand 2 stage air compressor. I had 2 motors burn up on me in the last 2 years. The air compressor has a 5 HP motor. The 5 HP motor does not have a magnetic starter. I was told that if it does not have a magnetic starter it's not actually a 5 hp motor. True 5 HP motors will have a magnetic starter???? Well anyway I occasionally use my Bead blast cabinet to blast parts. This is the part that makes me really wonder. 2 years ago I switched from Garnet abrasive to glass beads. I emptied the garnet and put a 50 lb bag of fresh glass beads in the cabinet. I put my parts in the cabinet and got to my second part. Kicked a circuit breaker and smoked the motor. I went out and bought a new Century motor with the exact same specs as the original compressor motor. It was good for 2 years. Took the glass beads out of cabinet and went back to garnet abrasive again for heavy rust scale.Not a problem for 2 years. Today I changed over to glass beads again and ran the compressor for 1 hour. What do you know, the compressor motor pukes on me. I am very aggravated. Has anyone had trouble like this before???? If someone can explain to me what's going on here please do so. My bead blast cabinet has a vaccuum attachment to rid of dust in the cabinet but I'm sure there is some dust from the glass beads that escape and get sucked into the air compressor motor. Is it the glass bead dust that is burning my motors???? I just don't get it.
Unless you're blasting a lot longer when you switch media then it could be the dust. Hook up a light so that you can see the dust around the compressor and pray you're not breathing it if that's the problem. That dust is killer stuff.
Originally Posted by musclecars
You can pretty much rule out the blast cabinet having anything to do with the compressor motor going belly up. (that is other than the fact that a blast cabinet uses a LOT of air which the gives the compressor a good workout, including the compressor motor). What is the amperage rating on the compressor motor that just died and ballpark how much does that motor weigh ?
My Quincy 5 hp 2 stage 2 cyl 19 - 22 cfm compressor has a Baldor 220 single phase electric motor that weighs 105 lbs without the dual belt cast iron belt pulley. It running amps is 22 and on startup it can draw upwards of 50 amps. The list price for that motor right now is around $750 and an excellent street price is around $450. It does use a magnetic starter. That motor is 6 or 7years old and the exact same motor that it replaced lasted around 20 years ( I bought a $40 part for the original motor and its sitting on the shelf ready to go again if and when needed). My point being that those small single or dual capacitive start "5" hp are not going to hold up on any compressor other than light occasional use.
Specs for motor
I must say that I agree with the replies. Ingersoll rand makes a good product. I must also agree that CFM usage for the bead blast cabinets is hard on the motor. I was thinking of upgrading to a better compressor with better CFM ratings. Ingersoll Rand claims that my compressor pump was designed for continuous duty and that it can take lots of abuse. Those cast iron pumps are built tough..I guess my only choice is to buy a better motor or upgrade to a better compressor...
Specs for motor
Century motor #B384 5SPL-3600 RPM-56HZ frame
This motor is a very common replacement motor for Ingersoll Rand motors.
Century / AO Smith electric motor #B384
•182T and 184T frame mounting holes, and a shaft height of 4.5"
•7/8" OD shaft * 2.25" length
•Capacitor start & Capacitor run
web link------------ http://www.grainger.com/Grainger/CEN...TA8?Pid=search
A 5 Hp motor and a magnetic starter work together. A magnetic starter is
Originally Posted by musclecars
a single phase or three phase switch, it does not make a motor a true 5 Hp
motor. That is a ridiculous thing that you heard.
If you do not have a motor starter then how is your compressor motor switched
on and off?
Having your motor burn up on you is too bad. Was it smoke from the windings
or did you have a bearing failure? What were the last two motors? Are you using
single phase or three phase?
If you had a motor starter with overload protection and a circuit breaker you
would have protection for the motor and wiring.
Your bead blasting has nothing to do with your motor troubles, unless you are
constantly putting demand on that compressor or the motor is too small in rating
for the pump. From what you said that does not appear to be so.
Another thing that is hard on them, is lack of a good/strong power supply..if it`s struggling/dragging on start up, it`s staying in that higher amp draw mode for far too long..as mentioned above, they will draw alot more amps on start up then when running at speed...
so if it`s running slower due to a cold compressor "pump" that is really holding it back, or lack of a good strong power supply....it won`t last near as long as it should..
A true 5hp motor, is a heavy beast, and defiantly not cheap..
Originally Posted by rons
The first motor was the original motor from Ingersoll. The second one was a (AC Century) motor from grainger supply. It had the exact same specs. It appears that the motor windings are burnt. If you look in the motor casing you can see little tiny burnt copper windings. It is what it is now and there is not a thing I can do about it. Something is eratically wrong here and I got to find out what is causing this. I must start some where.
The thing that comes to mind as most likely the problem is low voltage at the motor. What size wire comes to the compressor, and how long of a wire run is it back to your main electrical entrance box? Be sure nothing else is hooked to that circuit. Is your main electric entrance large enough to handle the entire load that is hooked to it? I am only assuming this compressor is at your home shop. You may have a 60 year old house with a 100 amp service or less. If that is the case you will get low voltage when your wife is using the oven and drying cloths while the water heater is on and your compressor kicks in. A newer home with a 200 amp service will do better under those conditions. Hopefully you have 10 gauge wires going to the compressor.
Starting the motor under low voltage can cause it to burn up. Too small of a service wire will cause low voltage. The switch that controls the compressor may need to be replaced. If the contacts are burned they will cause a voltage drop. If you are using the same switch with all of those motors then suspect the switch.
I agree it could very well be a voltage/amperage delivery problem to the motor. But there are a whole long list of things that would help to burn up a motor. Lets start with the magnetic starter (or lack there of). A magnetic starter for an air compressor is similar to a starter solenoid on a car. Without the solenoid in the circuit then every time you started your car you would have enough amperage going through the ignition/start switch that it would almost immediately burn that switch out. Instead of high amperage wires going through the ignition/starter switch you have a small low amperage wire that goes from the starter switch in the steering column to a small electromagnet in the starter solenoid. When you turn the key to start the car it energizes that low amperage electromagnet in the starter solenoid. When the electromagnet in the solenoid energizes the magnet pulls a small iron cylinder. When that small iron cylinder is pulled by the electromagnet it touches two terminals that complete the high amperage circuit from the battery to the starter motor. Bottom line is -- with the use of that low amperage electromagnet there is no damaging high amperage going through the steering column key activated starter switch so the starter switch will last a long time instead of burning out almost immediately. The magnetic starter on an air compressor does the same thing as that starter solenoid on a car. Only the pressure switch on an air compressor is what takes the place of a key activated starter switch on a car. Without that magnetic starter on an air compressor it is sending up to 25 amps through the on/off pressure swtich. Every time the air pressure drops to where the electrical contacts close and complete the circuit sending voltage/amperage to the compressor motor it causes an electrical arc in the contacts of that pressure switch. Every time those contacts arc in the pressure switch a small amount of contacts are burned off, vaporized. The larger the amount of amperage that goes through those contacts the stronger and bigger the electrical arc is going to be. The bigger the arc the more area of those contacts are burned off.
What all that means is -- without a magnetic starter the contact points in the on/off pressure switch will fry a lot faster. Before those contact points get totally burned off to where they no longer allow current to pass through they will become intermittent bad where the amperage allowed through is less than would be with new contact points. Lesser amperage to the motor is like your heart not sending enough blood to your brain with intermittent malfunctions and not too long permanent brain damage.
Thats only one scenario that can cause an electric motor to fail. Burned contacts in your main on/off switch that you use to turn on and shut off the air compressor can also cause an amperage to the motor delivery problem. The contact points in your electrical circuit breaker panel that feeds the line going to the air compressor can also cause an amperage delivery problem to the compressor motor. As previously stated the problem could be too small of a feed line from the circuit breaker panel to the compressor.
I realize its a pain in the butt to pay an electrician to come out and check your electrical supplies ability to get the proper voltage/amperage to the compressor motor. But at this point in time you really need to rule out that as the cause of those motor burning up.
Have those motors been open to paint fumes/overspray in your shop while you're spraying primer and paint ? Bondo dust and sanding dust can clog up the cooling passages in those motors which will cause the motor to run hot (and eventually burn up). The original Baldor 5 hp motor on my Quincy was fan cooled open type motor (could collect dust and paint overspray inside the motor around the copper windings etc). Around 7 years ago I replaced that open fan cooled motor with a totally enclosed 5 hp Baldor motor and obviously haven't had a problem with dust and paint overspray building up in the motor. This is the replacement motor I put on my Quincy 7 years ago ----- http://www.baldor.com/products/detai...ing=40CMB-CONT
I paid $450 for that motor 7 years ago
If you are running a tank up to 175psi or higher then you are asking a lot from
your motor. You can adjust your switch to 150psi or a little lower. Adjust the
range for 25psi. Inside your switch there are two adjustment screws you can
Another thing that comes to mind is that if you do not have a good solid neutral
wire connection to your house/shop your motor will experience under voltage. I
found this out because a squirrel chewed my aluminium neutral wire in half.
One other thing. Are you familiar with what a start capacitor is. Single phase
motors need them to start. Eventually any single phase motor will fail in this
way, depending on factors such as quality, frequent starts, age, etc. Start
capacitors are inside those metal cans on your motor housing.
Ditto on the low voltage. Neutral is only an issue if your motor is 120V. 240V doesn't use neutral. A 200A service should be plenty, but use at least a 30A breaker and #10 wire to the starter (yes, you should use a starter). Big wire is always better, make the power cord as short as possible, or better yet, hard wire right to the motor. Ohm's Law, you know!
Phil is right on with the mag starter issue. I have seen compressors sold with out a starter (mine was that way) and the maker's warranty clearly stated that no mag switch, no warranty.
Get a starter on the thing.
I think Phil is right on the money!
My Husky "3 running HP" compressor just died due to a burned out motor.....same exact description as the OP stated. My local electric motor supply repair guy says these are special motors made just for these cheaper compressors and have heavier wire and other minor improvements inside to make enough power, and that they are not a true hp rated motor, any motor thats labeled spl or 5spl on the tag in the hp rating window and draws only 15 amps is this type of motor. My windings were burnt also and the starting capacitor end cap was blown off and the run capacitor had a melted terminal. Phil's theory of the pressure switch contacts arcing makes a lot of sense and I plan to examine mine before installing the new motor.
No 15 amp motor is a real 3 hp, how many amps is the op motor?
Never heard of these "special motors". I have heard of "compressor duty" motors.
Originally Posted by C10Chas
If the windings use heavier magic wire why are they burnt up?
If you keep using these "cheaper" compressors use 240 instead of 120 supply.
No explanation should be necessary.
I know this isn't an answer to your question but here is one bit of advice I learned along the way. Take that motor to your friendly neighborhood mom n pop electric motor shop for a look see. That, like my other favorite place, the local small starter and alternator shop will be best to check it out, figure it out and get you set up right. The last couple motors I bought ended up costing me a lot less than I could have gotten from any local supplier and even the internet. That was a real surprise to me but saved me a lot of cash. Besides that they can usually tear yours down quick and tell you what happened. In the last headache case I had with an overheating treadmill motor he yanked it apart tested it in 10 minutes and told me to put it back together and be happy that it was hardly worn. Sometimes there is no substitute for professional experience.