Announcement

Collapse
No announcement yet.

How to reverse motor rotation.

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • How to reverse motor rotation.

    I have an older motor.. it spins the wrong way...

    Wierdscience gave me some advice to switch motor leads 5&8 to reverse the motor. Only problem is there are only 2 wires coming out of the motor......

    What to do?

    Edit to add: Of course there isnt an diagram either... When I look in the motor, there is a small circuit board, but thats it..
    Last edited by cuemaker; 10-22-2009, 11:51 PM.

  • #2
    Originally posted by cuemaker
    I have an older motor.. it spins the wrong way...

    Wierdscience gave me some advice to switch motor leads 5&8 to reverse the motor. Only problem is there are only 2 wires coming out of the motor......

    What to do?
    Post a picture of the end of the motor the wires come out of and maybe any name plates on the motor, An overall picture of the motor would help too. All this is a PITA, but will help those of us not familiar with the situation to make some suggestions.
    Design to 0.0001", measure to 1/32", cut with an axe, grind to fit

    Comment


    • #3



      Comment


      • #4
        ummm, the motor has been cleaned by the way.....New NSK bearings also...used all those spring washers that you can see in one of the pics to press the bigger one in...rather lucky I had those handy...

        Comment


        • #5
          It will help if you open up the junction box on the side of the motor housing, where the cord goes in, and take a picture of the leads.

          Also, the motor nameplate, which should also be on the housing. The picture you show with the two wires is the overload switch and reset button, not the motor leads.

          Comment


          • #6
            looks like a classic repulsion motor, unless it is actually DC......or universal....... several possibilities, which will look much the same.

            is there any data plate on the motor?

            I am assuming you would mention that it was DC if it was. So repulsion is most likely. Unless there is stuff on the end I can't see, does not look like repulsion-induction, but could be, since the shorting bars don't take up much space and might not be visible, and those are more common.

            IIRC the rotation is reversed by shifting brushes , there may be a way to rotate them somewhat.

            Also can be done in a repulsion type (not repulsion start-induction run)by re-connecting the rotor (changing brush connections) That can be done to plug-reverse.
            1601

            Keep eye on ball.
            Hashim Khan

            Comment


            • #7



              Comment


              • #8
                Originally posted by J Tiers

                IIRC the rotation is reversed by shifting brushes , there may be a way to rotate them somewhat.

                Also can be done in a repulsion type (not repulsion start-induction run)by re-connecting the rotor (changing brush connections) That can be done to plug-reverse.
                I can take out the thing holding the 4 things (i assume they are the brushes since they ride on the small copper part) and rebolt them into any of (4?) positions... in fact, while putting this thing back together i didnt bolt it in in the same position....

                Comment


                • #9
                  That looks like a repulsion-induction motor. You should be able to change the direction of the motor by changing the position of the brushes with respect to the field poles.

                  Look at the picture showing the brush-holder (the third picture in post #3). The large poles of the stator are at the 0, 90, 180, and 270 degrees. The brushes are at (approximately) 35, 125, 215, and 305. If you shift the position of the brush mounting plate about 20 degrees clockwise so the brushes are at 55, 145, 235, and 325, the rotation should be reversed.

                  I can't tell for sure from the photo if the brush mounting plate can be moved to that position, but it looks like the clamps under the screws at 90 and 270 could be loosened to allow the plate to be moved.

                  The brushes short the armature to produce a torque at low speeds. The torque direction depends on the offset of the brushes with respect to the stator poles. Once running, it works like an induction motor.

                  Roger
                  Last edited by winchman; 10-23-2009, 03:29 AM.
                  Any products mentioned in my posts have been endorsed by their manufacturer.

                  Comment


                  • #10
                    changing the brush holders postion will change the direction and speed of the motor, but you might find that tricky if its not deisned to do that.
                    It looks like there are just 2 wires comming from the stator (outer stationary windings), if you reverse the connections of those 2 wires then your rotation should reverse.
                    Brush motors are noisy critters, but give decent power for their size.
                    Build it, bodge it, but dont buy it.

                    Comment


                    • #11
                      4 brushes and 4 clear field windings.

                      It's either a series or shunt wound motor. With both of them reversing the polarity of the field also reverses the polarity of the armature so they continue to run in the same direction. You can power them from both AC and DC.

                      Given the low rpm rating, it's almost certainly shunt wound, which unlike series has a more or less linear rpm per volt characteristic.

                      As has been said, reverse the field in relation to the armature to reverse rotation, but you'll also need to reset the brush angle.

                      If you look at the picture showing the brushes and field coils, you'll see that the brushes don't quite line up with the point at which the field coils butt up against each other. That's the timing angle (just like ignition timing) and you would need to set the timing to the other side of the gap. The motor would run without doing this, but the speed/torque/efficiency would be different.

                      Once you've reversed the motor, run it no load for a few hours to reseat the brushes.
                      Paul Compton
                      www.morini-mania.co.uk
                      http://www.youtube.com/user/EVguru

                      Comment


                      • #12
                        Originally posted by EVguru
                        4 brushes and 4 clear field windings.

                        It's either a series or shunt wound motor. With both of them reversing the polarity of the field also reverses the polarity of the armature so they continue to run in the same direction. You can power them from both AC and DC.

                        Given the low rpm rating, it's almost certainly shunt wound, which unlike series has a more or less linear rpm per volt characteristic.
                        Look at dataplate..... 1750RPM AC.... That means it is NOT a DC shunt or series motor...


                        The big copper ring indicates a repulsion start induction run motor. At speed, it should be moved by a system of weights and levers inside the hub to short the end of the commutator bars ("copper ring things")....

                        The brush position should adjust to change direction. IIRC the direction should adjust LESS than 90 deg to do it, and should adjust in the direction you want the motor to turn. The angle is since that is a 4 brush motor, and a 90 deg movement would likely only reproduce the same conditions as now.

                        Since it runs as an induction motor, the start direction determines the run direction,. That 1750 RPM is also typical of an induction motor.


                        I found a decent reference, although it shows a 2 pole motor.

                        http://books.google.com/books?id=CxQ...tor%22&f=false
                        1601

                        Keep eye on ball.
                        Hashim Khan

                        Comment


                        • #13
                          Motor

                          The unit is a typical repulsion start- induction run motor. The brush holder assembly can be rotated to reverse the direction of rotation. The view of the brush holder unit shows an indent mark on the top side of the unit. Loosen the two clamp screws and rotate the assembly to line up with another index mark on the end bell casting. The rotor has one winding that is much darker than the others indicating a possible bad connection at a commutator bar of internal short. The commutator need to be cleaned up.
                          This type of motor is great for hard starting systems.

                          JRW

                          Comment


                          • #14
                            "The view of the brush holder unit shows an indent mark on the top side of the unit."

                            Good observation!! I missed the mark, but what you suggest agrees with what I thought might work.

                            Roger
                            Any products mentioned in my posts have been endorsed by their manufacturer.

                            Comment


                            • #15
                              Guys, could it be as easy as this?? Take a look at this new pic....

                              At the top where the 2 bolts are, is a plate with a finger... on the round plate that holds the brush, are 2 slots... I currently have the finger in in the right most slot.

                              Is it enough movement to go from one slot to the other in order to reverse the direction?

                              AND, i am not asking if this current config is right, as I intend to put it back into the condition it was when I took that earlier pic, and then shift it to see if it moves it right...

                              But over all, just moving the brushes that little much sound right?

                              Thanks all!!!! you have been a big help in teaching me new things.

                              Comment

                              Working...
                              X