I have a Craftsman Air Compressor, #921.153101, that all of a sudden acts like it's being given half volatage. The motor runs, but the contacts are rapidly opening and closing, and the motor is running at about 1/2 speed. I put power directly to the wires going to the motor, bipassing the regulator value, same result, so I know the pressure valve is not causing it. I'm guessing it might need Part #E100247, Running Capacitor, but I don't know. Is there some kind of test I can perform before getting the new part and hoping I guessed right? thanks, John
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you must have wired the new pressure switch incorrectly .when the pressure switch opens it will release the head pressure so your compressor must be running with the pressure switch contacts open should be 4 connections 2 marked motor which is from your compressor and 2 marked line which is your power coming in
The electric motor may have seized up from moisture or contamination. Make sure all air has been released by opening a valve or fitting.Disconnect the compressor from its power source, (Tape the power cord plug to compressor handle for extra safety) Remove motor cover, try to rotate the motor with a screw driver using just a little pressure.If the motor has brushes, make sure they are in contact and do not need replacement. Check to see if the motor has lubrication points. If so us a little WD40 or other oil based product.Place cover back on motor. Plug unit in to power source. If the unit still 'hums' turn switch off. I believe this compressor is oil less.If so the motor and compressor may be connected as a unit.If the compressor itself is froze up you may be able to separate the two and try freeing any frozen parts, again making sure the unit is disconnected.If the compressor does not respond to the suggestions given consider replacement if out of warranty.Good luck!
Your Craftsman model 919.165200, 5hp, 20 gallon compressor was designed to run on 115~120v 15amp. I believe that it was made by Campbell Hausfeld and is of the oilless single cylinder type. If however your compressor is oil lubed and has a motor /drive belt configuration it may be able to convert if there is a spec plate on the motor with alternate wiring diagram. Many high-end compressors like Rol Air, Jenny, Dewalt, etc with motor/belt drive have a switch selectable voltage, however one must still change the power cord when using 220v. Good luck with your projects and post again if your have other question.
if the compressor turns over freely then you have a motor fault its likley to be a short in the windings causing it to loos power and therefore pull more amps this in turn pops your brakers as it is a 5hp 110 volt motor will pull nearly 45 amps witch if nearly half the power that my house runs on (but at 230 volts i have twice the pushing power)
Not the motor, but probably the compressor shot. Heat from friction (due to running without oil) probably scored the cylinder walls, which allows air to escape past the piston and rings, making the compressor VERY inefficient. Some compressors have replaceable cylinders... Not sure if the very small ones do or not.
Yes , the check valve will cause this. The check valve has a flat disk with a spring that holds it down that the air passing past it erodes away till it leaks then the air that the piston pushes into the tank does not stay in the tank but returns right back into the cylinder and puts a load on the piston. Also makes the compressor hard to start back up if it does get pumped up. Some have a dump valve that drains the pressure off the head after they shut off so it can start with no load. So if there is air bleading back and leaking at the pressure swith that will be a for sure sign it is the check valve.
I have repaired many craftsman compessors with the problem that you are having. I just use the process of elimination to find the broken wire. I use a short pigtail and attach it to the motor side of the pressure switch. This will isolate the motor from the switch and the power cord. Use caution not to overfill the compressor as this will test the safety valve. If the motor runs ok then move the pigtail to the powercord side of the switch. This will eliminate the power cord. If problem is within the motor check the connectors under plate and capacitor cover. To test the capacitor you will need to find a meter with cap test capabilities or repair shop will test for free. The cap should test within 95% or printed value in (uf). If all parts test ok then motor could have internal thermal breaker that is weak. Good luck.
Does this trip on pressure or is it a breaker tripping? If you took off the intake then there is no pressure build up, thus it wouldn't trip the pressure switch. But would at the same time add a load to the motor. First check and make sure motor is wired properly, then check that pressure switch is wired properly and is adjusted to the right pressure. I don't believe that the intake tube would be clogged, it's a straight hole into the tank. But could be a possibility.