Author Topic: brushed DC motor as a generator  (Read 5275 times)

Offline airmodel

  • Full Member
  • ****
  • Posts: 79
brushed DC motor as a generator
« on: February 14, 2014, 05:45:40 AM »
Hi everyone

After I visited the 2009 NAMES show I had a look at the Henry Ford museum. I liked the look of the old DC generators made by Edison at the museum, so four weeks later I made a working model.

 This is a very simple model as there are only two wires for the output and it does not matter which direction the generator spins. It was a 24 volt motor and to make it generate the amature is spun by a model motor.

The video shows what happens when only one magnet is used and it still generates DC.  http://youtu.be/yWF0mKSrsK4

Offline rockknocker

  • Full Member
  • ****
  • Posts: 13
Re: brushed DC motor as a generator
« Reply #1 on: February 14, 2014, 08:33:40 PM »
That is very nice looking! Those old motors and generators have a lot more "character" than modern ones do, for sure.

Offline airmodel

  • Full Member
  • ****
  • Posts: 79
Re: brushed DC motor as a generator
« Reply #2 on: February 14, 2014, 10:44:19 PM »
 rockknocker  Welcome to the forum.

Offline Don1966

  • Full Member
  • *****
  • Posts: 5938
  • Morgan City, LA (Along the Gulf Coast)
Re: brushed DC motor as a generator
« Reply #3 on: February 15, 2014, 12:41:56 AM »
Airmodel being in the electrical field I can appreciate your project. That is a nice setup and a great looking generator. I like.......... :praise2:

Don

Offline b.lindsey

  • Global Moderator
  • Full Member
  • *****
  • Posts: 13256
  • Dallas, NC, USA
    • Workbench-Miniatures
Re: brushed DC motor as a generator
« Reply #4 on: February 15, 2014, 01:19:07 AM »
Airmodel, as I have said before, I don't so the sparky parts but love the castings and the finished result. Sure looks like it is working well to my untrained eye.

Rockknocker, if you will, please post and bit about yourself in the intro section so we can get to know you and your interests.

Bill

Offline Ian S C

  • Full Member
  • ****
  • Posts: 1032
  • Stirling Engine Maker Darfield Canterbury N Z
Re: brushed DC motor as a generator
« Reply #5 on: February 16, 2014, 12:07:25 PM »
Airmodel,  looks a good one, I too convert old electric motors into alternators, and generators, I use them as a load for my hot air/Stirling engines.     Ian S C

Offline steamer

  • Global Moderator
  • Full Member
  • *****
  • Posts: 10101
  • Central Massachusetts, USA
Re: brushed DC motor as a generator
« Reply #6 on: February 16, 2014, 12:14:28 PM »
Hey Airmodel,

I like that a lot.   It's nice to put the engines we make on a load and make them do something.    this is a perfect way to do it!

Nicely made ! :ThumbsUp:

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline zeeprogrammer

  • Full Member
  • *****
  • Posts: 6372
  • West Chester, PA, USA
Re: brushed DC motor as a generator
« Reply #7 on: February 16, 2014, 12:59:50 PM »
That looks great. It would look swell too in a diorama of some sort.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.

Offline airmodel

  • Full Member
  • ****
  • Posts: 79
Re: brushed DC motor as a generator
« Reply #8 on: February 16, 2014, 11:45:40 PM »
Don  I have no formal training in electricity. All I know is self taught. It is good to see that others are interested in the same thing.

 Bill  I was hoping that you would see this post. DC generators are very simple to understand. The only thing you have to watch is keep the brush alignment the same as it was in the motor.

Offline PStechPaul

  • Full Member
  • ****
  • Posts: 688
  • Cockeysville, MD 21030
Re: brushed DC motor as a generator
« Reply #9 on: February 22, 2014, 08:59:49 AM »
Nice looking little motor/generator. The casting process is impressive! Did you also make or modify the armature? And where did you get the curved magnets for the field?
 
My interests at the moment are three phase AC induction motors (3 cheers for Tesla!), and switched reluctance motors which use only electromagnets and iron.
 
I recently saw the movie "Edison the Man" where he had built two huge dynamos to power the lights on a street to demonstrate their superiority to gas, and he had a problem with synchronizing them and they burned up. But then he had the idea of connecting the governors together and it worked. But I don't know why he had to connect two in parallel. He could have used two separate circuits. And I suppose they didn't have fuses and circuit breakers in those days either? Probably they did, but then they would not have been able to shoot such a dramatic scene with big sparks and noise and smoke! Even in more modern and futuristic movies and shows like "Star Trek", they always have exploding control panels, while that would almost never happen in a well protected and properly engineered system.

Offline Ian S C

  • Full Member
  • ****
  • Posts: 1032
  • Stirling Engine Maker Darfield Canterbury N Z
Re: brushed DC motor as a generator
« Reply #10 on: February 22, 2014, 11:02:10 AM »
On one generator, and one motor that I have built from scratch, I mounted the brushes so that they can be rotated about 90* either side of there normal position, I like fiddling around with things, that way with the motor there is some speed control, as the load goes on, it can be adjusted for the least sparks at the comutator, It's an open frame motor, and it will run my "Super Adept" lathe with ease, and has more than enough power to run my power hacksaw(Junior blades).    Ian S C

Offline steamer

  • Global Moderator
  • Full Member
  • *****
  • Posts: 10101
  • Central Massachusetts, USA
Re: brushed DC motor as a generator
« Reply #11 on: February 22, 2014, 11:04:06 AM »
As I understand it....and I might not....it was a phasing issue ....regarding Edison and his generators.

Coupling the two governors together would result in one driving the other....which is fine I suppose.   It just means 1 of the inputs of the dynamic system was removed...and there must have been a fixed gain added to the other engine throttle...

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline Don1966

  • Full Member
  • *****
  • Posts: 5938
  • Morgan City, LA (Along the Gulf Coast)
Re: brushed DC motor as a generator
« Reply #12 on: February 23, 2014, 03:24:34 PM »
In order to parallel the Dynamo's, a means to control the voltage had to be installed or one generator would feed into the other. Just like connecting two batteries together with different voltages. The high voltage battery will charge the lower voltage battery and it would probably blow up. Then in order to have both pulling the same load the governor had to be adjusted the same or one would put out more power then the other. In other words load one engine more then the other.

Don

Offline vcutajar

  • Full Member
  • ****
  • Posts: 2455
  • Marsascala, MALTA
Re: brushed DC motor as a generator
« Reply #13 on: February 23, 2014, 04:32:12 PM »
This is all reminding me, when in the good old days on the 707, we had to parallel four AC generators by adjusting the phase of each generator.

Vince

Offline Don1966

  • Full Member
  • *****
  • Posts: 5938
  • Morgan City, LA (Along the Gulf Coast)
Re: brushed DC motor as a generator
« Reply #14 on: February 23, 2014, 04:48:16 PM »
This is all reminding me, when in the good old days on the 707, we had to parallel four AC generators by adjusting the phase of each generator.

Vince
Hi Vince, the setup we had when I was in school we had to adjust the phases in order to parallel, because the generators were on the same shaft and the winding were not set in the same identical position to each one. There was a crank to rotate them.
When you have different prime movers you don't have to shift the phasing other then to match phase rotation. But provision are made to be able to parallel them at the proper moment or in sync as it's called.

Don

Offline PStechPaul

  • Full Member
  • ****
  • Posts: 688
  • Cockeysville, MD 21030
Re: brushed DC motor as a generator
« Reply #15 on: February 23, 2014, 07:58:35 PM »
It's called a synchroscope:
http://www.selco.com/Products/Products/M8100%20Synchroscope.aspx
http://nuclearpowertraining.tpub.com/h1011v4/css/h1011v4_98.htm
http://www.industrial-electronics.com/elecy3_13.html
 


http://en.wikipedia.org/wiki/Synchroscope



These are for AC. For DC you just need to match the voltage, which is a function of RPM as well as the field current. I don't know exactly what type of dynamo was used by Edison, and I could not find any reference to the problem of synchronizing them for parallel operation for his demonstration. The arcs and sparks and smoke, as well as the all-night effort to rebuild them to meet the deadline, were probably Hollywood drama.
« Last Edit: February 23, 2014, 08:10:02 PM by PStechPaul »

Offline Don1966

  • Full Member
  • *****
  • Posts: 5938
  • Morgan City, LA (Along the Gulf Coast)
Re: brushed DC motor as a generator
« Reply #16 on: February 23, 2014, 08:49:23 PM »
I am familiar with AC sync scope. But you don't need a sync scope to parallel a generator, as two light bulbs connected between generators will do.
You don't need to sync a DC generator to get it on line together, the voltage and engine speed have to be controlled in order to load share properly. On a DC generator more so the voltage. A shunt generator you have to control the voltage in order to load share, on a compound Generator an equalizer jumper parallels the series field which makes it load share very well, because the load goes through each generators series field.

Don

Offline airmodel

  • Full Member
  • ****
  • Posts: 79
Re: brushed DC motor as a generator
« Reply #17 on: February 23, 2014, 11:50:35 PM »
PStechPaul   There are no modifications to the armature. The motor I used for this generator came from a heater/airconditioner fan. The magnets were part of the original motor.

To those who have little understanding of why there are problems running generators in parallel, think of two electric motors connected together that run at two different speeds. Very soon the motors will overheat and flame, smoke will surely happen.