Answers.Body: <p>The 12v train motor uses 2-pole 3-slot technology.</p>
  
  <p><img src="https://i.sstatic.net/7hmWZ.gif" width="300" height="150"></p>
  
  <p><img src="https://hackadaycom.files.wordpress.com/2011/10/motor.jpg" width="300" height="225"></p>
  
  <p>Because of thinner, but longer wire which results in a greater resistance and will create higher voltage, but lower current the current output isn't enough to drive on-train lights.
  Since the resistance of on-train lights is constant this will drag down the generated voltage as well.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-08-27T14:39:39.280Z
Answers.Text: I have since sold my 12V motor so I can't try this, but if one connects a voltmeter to the bogie motor, and watches the current, based on what you've said, there'd be a slight reading. Is this correct?
Answers.UserDisplayName: CJBS
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-09-01T23:02:26.820Z
Answers.Text: @CJBS yes. If you have a small LED you might see some light (if it's connected the right way round).
Answers.UserDisplayName: Móż
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-08-27T09:50:52.077Z
Answers.LastActivityDate: 2015-08-27T10:22:13.713Z
Answers.LastEditDate: 2017-03-10T09:42:48.927Z
Answers.UserDisplayName: Niels
Body: <p>This question is somewhat related to a <a href="https://bricks.stackexchange.com/questions/6348/will-playing-with-a-12v-train-motor-by-hand-damage-it">similar question</a> I asked about whether pushing a 12V train motor (such as the one below) would damage it.</p>
  
  <p><a href="https://i.sstatic.net/Dxskq.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/Dxskq.jpg" alt="enter image description here"></a></p>
  
  <p>See title "Set 7865: six wheeled Lego® train motor (12V, 1980 - 1990)" on <a href="http://horst-lehner.mausnet.de/lego/ben/9v_12v.html" rel="nofollow noreferrer">this page</a> for the specific motor I'm referring to.</p>
  
  <p>Irrespective of whether damage occurs to the motor when being pushed, I'd like to know why, given it contains a DC electric motor, when the gears are pushed by hand, electricity isn't generated by the motor in order to provide current to any connected load (e.g. the lights on the train).</p>
  
  <p>I've noticed that the connected headlights in <a href="http://lego.wikia.com/wiki/7740_Inter-City_Passenger_Train_Set" rel="nofollow noreferrer">the train</a> don't illuminate when pushed by hand -- is there some sort of electronic protection to prevent it being used as a generator?</p>
  
Tags: <trains><motor><12v>
Title: What prevents a 12V motor, when pushed by hand, from providing DC electric out?
UserDisplayName: CJBS
ThreadText: # What prevents a 12V motor, when pushed by hand, from providing DC electric out?
  
  (Asked by: username_0 on 2015-08-27)
  
  This question is somewhat related to a [similar question](https://bricks.stackexchange.com/questions/6348/will-playing-with-a-12v-train-motor-by-hand-damage-it) I asked about whether pushing a 12V train motor (such as the one below) would damage it.
  
  [![enter image description here](https://i.sstatic.net/Dxskq.jpg)](https://i.sstatic.net/Dxskq.jpg)
  
  See title "Set 7865: six wheeled Lego® train motor (12V, 1980 - 1990)" on [this page](http://horst-lehner.mausnet.de/lego/ben/9v_12v.html) for the specific motor I'm referring to.
  
  Irrespective of whether damage occurs to the motor when being pushed, I'd like to know why, given it contains a DC electric motor, when the gears are pushed by hand, electricity isn't generated by the motor in order to provide current to any connected load (e.g. the lights on the train).
  
  I've noticed that the connected headlights in [the train](http://lego.wikia.com/wiki/7740_Inter-City_Passenger_Train_Set) don't illuminate when pushed by hand -- is there some sort of electronic protection to prevent it being used as a generator?
  
  **Tags:** trains, motor, 12v
  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2015-08-27. Score: 7 | Accepted answer
  
  The 12v train motor uses 2-pole 3-slot technology.
  
  ![](https://i.sstatic.net/7hmWZ.gif)
  
  ![](https://hackadaycom.files.wordpress.com/2011/10/motor.jpg)
  
  Because of thinner, but longer wire which results in a greater resistance and will create higher voltage, but lower current the current output isn't enough to drive on-train lights.
  Since the resistance of on-train lights is constant this will drag down the generated voltage as well.
  
  > **Comments:**
  > **username_0**: I have since sold my 12V motor so I can't try this, but if one connects a voltmeter to the bogie motor, and watches the current, based on what you've said, there'd be a slight reading. Is this correct?  
  > **username_2**: @username_0 yes. If you have a small LED you might see some light (if it's connected the right way round).  
  
  ---
  
  