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Old Wagner electric 1 HP 1 phase Type RA motor

Discussion in 'Sensors and Actuators' started by jarhed73, Oct 6, 2016.

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  1. jarhed73


    Oct 6, 2016
    Does anyone know what to type of oil to use? The motor has two grease zerts, one on each end of shaft, as well as what appears to be drain plugs.
    Serial for motor is J263 K4056 It is an a 1947 model Delta Crescent 20 '' bandsaw serial 938-B
    upon removing one drain plug and the two zerts, nothing drained out, and existing oil looks like thick type grease.

    Attached Files:

    Last edited: Oct 6, 2016
  2. hevans1944

    hevans1944 Hop - AC8NS

    Jun 21, 2012
    They are called zerk fittings, not zerts. You use them with a motor-bearing grease, not oil. The zerk fitting has a simple ball-and-spring one-way valve that allows you to insert grease through it, and subsequently through the motor bearings, under moderate pressure, displacing the old grease that was there. You can use a hand-pumped grease gun to pump new grease in, forcing the old grease out through the drain holes. Be sure to replace the drain plugs after re-filling the bearings with grease. A small sample, a teaspoon or so, of the old grease could also be dissolved in a solvent (try mineral spirits or isopropyl alcohol or kerosene... do not use gasoline!) and the residue inspected for metallic contamination. A magnet can be used to pick up fine particles and you should be able to feel if there is "stuff" attracted to the magnet. Any metallic contamination is bad news and, if found, the motor should be disassembled, cleaned, and the bearings replaced.

    Before going to all that trouble, check the motor shaft to make sure the bearings haven't seized. It should turn freely by hand without scraping or binding. If not, then you will have to disassemble the motor to remove and clean or replace the bearings. I recommend taking it to a motor repair shop to make sure the work is done right and the correct replacement bearings (if you need them) are installed. Original equipment manufacturer (OEM) bearings may be hard to find for a motor this old, but if careful measurements are made you may be able to find suitable replacements. Again, a motor-repair shop is the best bet for this.

    As for which grease to use... you are on your own there. Maybe visit a motor repair shop for recommendations. I had a quart-sized can of Bodine motor grease that I kept around for years without putting a significant dent in the volume, but Bodine motors are generally small compared to the honker you have. You can probably get away with any "brown" grease about the consistency of Crisco that an auto supply store will have. I wouldn't waste money on exotic blends. Grease guns are cheap too, maybe even one purchased from Harbor Freight would work "gud enuf" to get your motor running.

    From your photo, this appears to be an excellent induction motor needing only a bit of TLC. Maybe seal all external holes (if you don't take it apart) and have it sand-blasted and powder-coated with a new paint job. It should give you many years of good service if the windings and bearings are in good shape.
    darren adcock likes this.
  3. Tha fios agaibh

    Tha fios agaibh

    Aug 11, 2014
    I agree with Hop.
    I doubt it uses any oil. I'd grease the zerk fittings and call it good.
    The only non-grear reduction type motors I've seen that take oil use an oil cap over the bearings and use 3 in 1 oil.
  4. jarhed73


    Oct 6, 2016
    Thanks. Hop. Motor runs fine w/o any noise from the bearings, which is amazing to me. I have been able to check the bearing on one end, but cannot remove pulley to peek at that bearing. Motor needs a good cleaning and will replace grease once cleaned.
  5. hevans1944

    hevans1944 Hop - AC8NS

    Jun 21, 2012
    Amazing, hell! They really knew how to build good motors back then: good steel ball or roller bearings, lots of good silicon steel in the magnetics (rotor and stator), heavy-gauge OFHC (oxygen free high conductivity) copper in the windings (probably), heavy-duty insulation on the copper, and a forged steel case to hold it all together. You buy a 1 HP, single-phase motor today and you are lucky if it lasts two years. Modern manufacturing really pushes the envelope to reduce production cost. You can pass your motor (and the 20" bandsaw it's attached to) down to your grandchildren.

    You may not ever need to remove that split-pulley, but if you do, buy or rent a gear puller and soak the keyed shaft in penetrating oil overnight before attempting to remove the pulley. The penetrating oil and the overnight soak are essential. Don't try to rush it. Sometimes it helps to heat the pulley with a torch so it expands slightly.

    The shaft key is sometimes wedged in so tightly that you have to try to move the pulley toward the motor face to free it. Place a steel cylinder over the end of the motor shaft and whack the pulley (not the key or the shaft!) with a leaded dead-blow hammer to move the pulley toward the motor case, away from the end of the motor shaft. Keep the whacking cylinder's outside diameter small, so the hammer impulse is transferred to the pulley, close to the shaft, nowhere near the outer edge of the pulley.

    Don't "drift" the pulley too far or the the gear puller won't fit behind the pulley! However, If that works, you can then usually remove the key with a pair of locking-jaw pliers (Vice Grips) and then use the gear puller to remove the pulley from the shaft. A deep-well socket wrench that fits over the motor shaft can be handy for use as a whacker cylinder, or just use a short length of iron pipe with one end ground flat and perpendicular to the bore of the pipe. If the pulley is pot metal or cast aluminum, a rubber or leather washer should be placed over the end of the pipe to cushion the hammer blow. Have a replacement pulley on hand in case this brute force attack damages the pulley. Pulleys are cheap, motors are not. Sometimes you have to sacrifice a pulley to get it removed from the motor shaft. The keys tend to rust into place over long periods of neglect.

    When you go to put the pulley back on the shaft, support the back side of the pulley with wooden blocks of appropriate thickness to position the pulley on the center-line of the drive belts. A pulley that is not centered properly will quickly wear out the belts. Once you have the pulley aligned, drive a new key between the slotted shaft and the inner diameter of the pulley using a drift punch and a ball-peen hammer. It just needs to be snug, so tap lightly.

    It probably isn't necessary to clean the inside of the motor. Just blow any dust out with low-pressure air. Maybe wipe dirt off the internal cooling fan blades if one is present. You might want to check the insulation on the individual wires of that external black cable. There is a tendency for the insulation to break down and crumble from exposure to ozone in the air. For something that old, I would replace the cable as a matter of principle with an appropriate gauge SOOW or SEOOW insulated cable.
    darren adcock likes this.
  6. Minder


    Apr 24, 2015
    I don't come across many motors with zerk fitting any more as most motor now use sealed bearings, they also tend to stay free of contamination, if replacing them anytime, it may be worth considering fitting the sealed variety.
    hevans1944 likes this.
  7. jarhed73


    Oct 6, 2016
    Hop. pulled old bearings and replaced. reassembled minus the pulley and applied new grease. Wanted to test run. Runs nice and quiet, but grease is squeezing our through holes in the hub. see attached. I don't have any washers that came off. but I did notice on the inside of the hub(both hubs) next to shaft that there are two grooves cut. I did not pull anything out of those grooves except old grease. Is grease supposed to come out of those holes during operation? Or is there supposed to be a disk on the outside to hold it in? IMG_0399.JPG
  8. eKretz


    Apr 8, 2013
    You probably overgreased. Almost certainly if you followed the earlier advice to grease until old grease was forced out the drain holes. You should never fill a bearing completely full with grease. It can add a significant amount of drag as well as cause problems with the excess grease getting places it shouldn't. Ideally you want to shoot for the amount of grease specified by the bearing manufacturer but you can get pretty darn close by using the following ballpark formula:

    Bearing diameter (inches) x bearing width (inches) x .114 = weight of grease needed in ounces. Pump out a full pump from your grease gun and weigh it with a postal scale, then convert that to how many pumps you need to lube the bearing through the zerk fitting. Be sure that you pre-fill the zerk and grease passage before assembly and greasing so that the grease pumped in goes directly into the bearing.
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