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Need to reverse rotation of a 2 hp Baldor single phase motor

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  • Need to reverse rotation of a 2 hp Baldor single phase motor

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    I picked up a replacement motor for my old FE Reid lathe. It’s a Baldor 2 hp 220 volt single phase capacitor start motor. There is only one diagram on the back of the wire cover plate and it does not indicate how the motor can be reversed. Adding 3 pics to show the current situation which has the motor running counter clockwise as viewed from the pully side. I have searched and not found an answer. Hoping someone can help me out. Thanks!
    Attached Files
    Last edited by Pmat; 04-11-2021, 03:59 PM.

  • #2
    Probably switch the red & black around. Can't see around the line & ground wires, but the red and black likely correspond to 3 & 4 on the wiring diagram. Better wait for the experts to chime in.
    Southwest Utah

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    • #3
      You need access to the start winding. Sometimes its leads are brought out, but not in your case. Which means that you'll have to open it up. They are the ones to reverse.

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      • #4
        Originally posted by Bob Engelhardt View Post
        You need access to the start winding. Sometimes its leads are brought out, but not in your case. Which means that you'll have to open it up. They are the ones to reverse.
        The L1 and L2 posts do have leads attached on the backside, just hard to see and access. I think the lower post has a yellow lead attached.

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        • #5
          Hard to see, but in the photo it looks to me like red and black and connected to the same connector. Usually, "L1" and "L2" refer to main lines 1 and 2, that is, the power coming into the motor. You should not have to touch those - the ones with the screw terminals. I'm guessing that the tab left of LI, marked "3" is the one you care about, and that you may need to connect (I'm guessing) the red wire to that one. It looks like that wire has a "3" label on it.
          "A machinist's (WHAP!) best friend (WHAP! WHAP!) is his hammer. (WHAP!)" - Fred Tanner, foreman, Lunenburg Foundry and Engineering machine shop, circa 1979

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          • #6
            I have doubts you can reverse rotation on that one.
            NEMA frames with a Y,H, or Z in the frame label indicate it is non-standard to standard nema frames.
            Example: 56HZ is very common to air compressor motors, and every 'compressor motor' I ever saw could not be reversed because compressors are made to run in a standard direction rotation,
            56HZ does not specifically mean it is a compressor motor, but it is a very very common usage, and, I have 2 'compressor motors' on hand and both of them look just like your wiring, and both are 56HZ.
            your difference here is your 1725rpm vs 'compressor duty' motors 3450.
            Basically the HZ in the frame size is a wild card, and the maker can make it anything non-standard.

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            • #7
              I see the same thing that mickeyf sees. The wiring in the pic is for a 2-voltage motor, but the nameplate does not show that.

              The motor may not be easily reversible, since the connections as-shown do not appear to support reversing.
              2730

              Keep eye on ball.
              Hashim Khan


              It's just a box of rain, I don't know who put it there.

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              • #8
                With what is presented there is no way to know if reversing is possible without major surgery. The first thing to do would be to access ALL the available wiring points. These include both sides of the pictured terminal board, the capacitor wiring and the start switch would be very helpful. In these motors there are several "gotya" possibilities. As it is a 220 volt motor it is possible for the start winding to be either 220 OR 110. It does not matter, but that just opens more possibilities for mistakes. The goal to reverse a single phase motor is to reverse the phase relationship of the start and run windings. The way this is normally done is by reversing the connections of the start winding. It is normal for motor manufacturers, Baldor included, to have a standard motor design and change options simply by changing what is available in the connection box. For example, a motor may be 110/220 and/or reversible. The way this is done is by having 3 windings or sets of windings, 2 110 volt run winding and 1 110 volt start winding. This allows the user to change the connections to allow 4 different motor operating possibilities: 110 cw, 110 ccw, 220 cw and 220 ccw. Now with this same basic motor the manufacturer can eliminate or permanently make connections to make a motor with only 1 or 2 of those possibilities. This both simplifies connections for a dedicated use and allows premium pricing if someone wants maximum flexibility. Another plus is for resellers. They can stock one motor to replace four motors, thus reducing stock variance and space.
                OK, I got off subject.... Open up things and trace the connections to the windings. What you are looking for is the winding that connects to the capacitor. This is the start winding. If you can get to both ends of the actual winding, isolated from the other windings, you can reverse those connections and reverse the rotation. That is what is needed.
                The possible "gotya" is that it is common for one end of the start winding to be permanently connected to one end of the run winging and that connection laced and varnished permanently into the winding bundle. It is possible to find that connection and cut it open, but that is WAY beyond my recommending or describing how to do it. sorry.
                Let us know what you find and if you need any more pointers.
                Robin

                Happily working on my second million Gave up on the first

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                • #9
                  Try the 5 and 8 exchange of the next post. The no. 5 wire should be behind.
                  Last edited by Noitoen; 04-12-2021, 09:39 AM.
                  Helder Ferreira
                  Setubal, Portugal

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                  • #10
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                    Helder Ferreira
                    Setubal, Portugal

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                    • #11
                      Contact Baldor or take to a motor shop.
                      Retired - Journeyman Refrigeration Pipefitter - Master Electrician - Fine Line Automation CNC 4x4 Router

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                      • #12
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                        Originally posted by Noitoen View Post
                        Try the 5 and 8 exchange of the next post. The no. 5 wire should be behind.
                        The red wire which appeared to be 3 on the tag is actually labeled 8 on the wire itself. Pulled the wires off the backside of L1 and L2 the wire attached to the back of terminal L2 is yellow but labeled 4 , the wire attached to the back of L1 is blue and might be labeled 1 but not sure.

                        Attached Files
                        Last edited by Pmat; 04-12-2021, 10:52 AM.

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                        • #13
                          The diagram Noitoen posted is the one most similar to the motor in question, but yours has fewer wires.

                          I was unable to find the motor spec or any of the other numbers at the manufacturer's site. That spec number etc was "not found" on the searches I made. The motor has no catalog number, and may likely be a custom motor that is surplus, but has no publicly available information available.

                          In general, with a 115/230V motor (and maybe with some 230V only motors) the start winding is 120V, connected across one of the two 115V windings from "center" to a line terminal. In that case, the motor can be reversed by leaving the center connection alone, and transferring the line connection of the start winding to the other line terminal.

                          Those two start winding wires are usually labeled 5 and 8.

                          It is not clear in the case of that motor whether the ability to reverse is provided. But if a wire labeled "5" can be found, then it should be possible.

                          Wires labeled from 1 to 4 are normally run winding connections. If there is a split start winding them wires 5 thru 8 are normally start windings. For motors having only one voltage, 1 and 4 are normally provided as run winding connections, while 5 and 8 are provided for single start windings.

                          So your #4 yellow wire is labeled as if it is a run winding. You need to find a #5 wire.


                          Last edited by J Tiers; 04-12-2021, 11:27 AM.
                          2730

                          Keep eye on ball.
                          Hashim Khan


                          It's just a box of rain, I don't know who put it there.

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                          • #14
                            Check here
                            CD0002A02 (baldor.com)
                            L3516TM - Product Catalog - Baldor.com

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                            • #15
                              I don't see all those wires/terminals in his motor. The "J" terminal is missing, and not shown on the diagram for the wiring on the motor.
                              2730

                              Keep eye on ball.
                              Hashim Khan


                              It's just a box of rain, I don't know who put it there.

                              Comment

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