UFO-

I believe you are right.  The armature (resistor) should be able to double as the motor itself simply by adding field magnets.  We will have to see how the back-emf alters the system, but a very good idea and should absolutely be tried.  

This is just a theory- but it is very possible that the universal motor's back-emf may self-regulate the resistor's impedance - thus acting as a resistive tuning mechanism, locking in the balance.

This may make the system much easier to build for anyone, as all they need is a DC motor - and slight mods yield an entire commutator / resistor system with no need for a separate motor.

Excellent idea..  

Hi again guys.

I really like the idea of using the power going to the brushes to actually run the motor.  I am not sure that will work with the motor I modified.  If I remember correctly that motor is from an old vacuum cleaner.  So it is a 120 volt motor and would probably turn very slowly or not at all on 12 volts.  However it should be pretty easy to make the same  mod to a 12 volt motor.  And if you can find a 12 volt universal motor that would be even better because you can vary the speed of a DC motor by varying the current going to the field coils.  As you reduce the current to the field coils the armature will speed up.  I don't think I have one but I do have plenty of 12 volt DC motors.

I am right now pretty short on extra time so not sure how quick I can do a mod to another motor.  But I will see what happens to the one I have just to check it out.  I am in the process of remodeling a room for my wife and her quilting friends.  And that project has to come first.  But I try to squeeze in a little electronics once in a while.

Take care,
Carroll

Okay Guys,  we have a winner!!!  I removed the scooter motor from my universal motor.  I hooked up just one of the field coils to my variable power supply and adjusted it to 15 volts.  I connected the other power supply to the Floodrod circuit which means it also has power to the brushes.  It was slow to start so I upped the voltage from 12 to  20 volts and it took right off.  Then I started turning down the field voltage and the motor sped up just like a regular DC motor.  So we now have a powered variable resistance device that doesn't need an external motor.  The motor was turning pretty fast at 5 volts on the field coil.  The scope said the AC output signal was 30 Hz.  So that's not too bad for a cobbled together system.  Also with the higher voltage going to the brushes and coils the output went up to almost 2 volts from the 1.5 volts.  I have some ideas for a much better transformer setup but that will have to wait until I have more time.

Great ideas you two are having.  Keep them coming.

Carroll

Quote from: citfta on Jan 20, 2026, 02:16 PMOkay Guys,  we have a winner!!!  I removed the scooter motor from my universal motor.  I hooked up just one of the field coils to my variable power supply and adjusted it to 15 volts.  I connected the other power supply to the Floodrod circuit which means it also has power to the brushes.  It was slow to start so I upped the voltage from 12 to  20 volts and it took right off.  Then I started turning down the field voltage and the motor sped up just like a regular DC motor.  So we now have a powered variable resistance device that doesn't need an external motor.  The motor was turning pretty fast at 5 volts on the field coil.  The scope said the AC output signal was 30 Hz.  So that's not too bad for a cobbled together system.  Also with the higher voltage going to the brushes and coils the output went up to almost 2 volts from the 1.5 volts.  I have some ideas for a much better transformer setup but that will have to wait until I have more time.

Great ideas you two are having.  Keep them coming.

Carroll

Hello my friend,

Great news indeed!!

I also had another idea that would eliminate the slip ring...by using the Motor Ground Case as well as Armature shaft and/or laminated steel core....then running a wire from armature shaft or from its Laminated steel core to just one commutator segment (like you have it.)
As then adding from the outer motor metal casing or stator's laminated steel the wire to Battery as per Floodrod design.
I believe you will have the same result, without a Brush and a continuous slip ring assembly.
Note: Some motors have one brush to ground...it must be disconnected (well, you know that Citfta !)

Great work!!
Thanks for testing it!

Regards

Ufopolitics

PD: Only thing...Make sure your motor does not have full 'Plastic or Mica bearings'.!!...

Hi again.

Yes you could connect one segment to the armature shaft and then connect to the frame to pick up the changing power.  However that power would have to pass through the bearings on the armature shaft to get to the frame.  There are a few machines in industry that do that but they have a special conductive grease in the bearings.  Otherwise there will be some arcing and burning of the bearings which will shorten the life of the motor.  We could connect the commutator segment to the shaft and then just let a brush ride on the shaft without the slip ring.  That would eliminate the problem with the bearings.

Take care,
Carroll