On gluing magnets on a 30 volt Amco

[Norm]

Have to reglue the magnets....only thing 3 of the 4 were loose.....so am
not sure if they are NSNS or NNNN? because it has only 2 brushes ....
but they are 90 degrees apart....not 180 so anyone have one like
this?....(we wouldn't want to glue them in and discover they were glued in
wrong....would we ?)
I know that with 2 brush 180 degree apart or 4 brushes 90 degree apart the
magnets would usually be NSNS.
thanks in advance for any help.
Norm.

[equiluxe]

Use a compass to find the polarity of the one still glued on the one  directly opposite will be of the other polarity then the other two most likely dont matter as to what polarity as long as they are opposing poles within themselves. 

[Norm]

the brushes are like this +       
                                   O  -  
so logically in a 4 brush would be like this.....
                                   +       
                              - O  -
                                   +
and the magnets would be...

            N
       S   O   S
            N
am I thinking right ? at least that's the way I'm thinking unless someone
actually positiveabslutely knows and tells me otherwise.....thanks for listening
guys.....no I'm not being sarcastic.....lot of times just by having someone to talk
to the answer seems to materialize like magic....anyone ever had that happen?
Norm.

[tecker]

I think the armature creates a full loop so NS is the orientation . The magnets aren't Curved ?

[Norm]

yes they are curved.... one edge is N and other edge is S....and of course
you can turn them end for end to reverse polarity.....
possible to stick them in unglued temporarily slow speed 100 rpm to see which way
works best?

[mab]

yes they are curved.... one edge is N and other edge is S....and of course
you can turn them end for end to reverse polarity.....
possible to stick them in unglued temporarily slow speed 100 rpm to see which way
works best?

So they are not magnetised through the thickness? (i.e north on inside of curve and south on outside?)

then, if i understand the magnetization correctly, four can be arranged:-

   nn
s      s
s      s
   nn

or

   ns
s      n
n      s
   sn

my guess would be the 1st one, which would match your 4 pole  90° arrangement. (I suppose the rotor can be wound for 4 poles with just 2 brushes, and the 90° brush positions would suggest that.)

you could try passing current through the rotor and use a compass to see how many poles it has.

m

[Norm]

reply to mab.
I'm listening... hold on until I do a little experimenting.....but I know how to
arrange them so the edges of the magnets will be attracted to each other.
I'll send a picture later.....thanks for hanging in there for me guys (or girls).
Norm.

[Norm]

Okay my apologys to everyone....for not checking  better....
I find that of the 3 loose magnets, 1 of them when face to face
with the 1 that is still glued in is opposed to it....so they are both
n faced magnets , that leaves the other 2 s faced magnets , so I
figure  it will be   N
                    S         S
                         N
at least that's the way I'll do 'em ....Let you know how it turns out....
and thanks for listening !
Norm