Peco point motors 2: The Sequel

Following the previous discussion I have documented the techniques I use for mounting below and through the board, with the pros and cons of both. Guy

  Quoted Text Here  
But you havent told us how you are getting on !
Cheers, Simon

  Quoted Text Here  
One of the buggers still won't operate even with a CDU (and yes I did already knew about these, I had to build a second one because they don't function well at more than about 3' distance).
Does anyone know if the Aussie electronics bloke ships his CDU PCBs to the UK? I don't have the kit for etching or the enthusiasm for getting it, and building on Veroboard is always a bit of a chore. Guy

  Quoted Text Here  
You never did say what power source you are using ? Plus it is possible to wire them the wrong way round.
Cheers, Simon

[ob. Peco point motors]
  Quoted Text Here  
I've tried three power sources: a Peco CDU, a 12V DC line with a 2200µF can (charged via a 2k2 resistor) and directly on 16V AC.
What do you mean the wrong way round? Guy

wrote:
  Quoted Text Here  
So they try to close point when should be opening it.

  Quoted Text Here  
They have two solenoids, one drives on and one drives off. The problem motors usually drive one way fine but not the other. Guy

wrote:
  Quoted Text Here  
Probably a mechanical problem - coils out of alignment or something like that causing friction on the armature.

On Sun, 25 Jul 2010 11:51:20 +1200, John Nuttall
  Quoted Text Here  
Every Peco point motor I have see has been so sloppy beteeen armature and coils that bits of ballast or moths could squeeze through.
Greg.P.

On Sun, 25 Jul 2010 08:16:31 +1200, Just zis Guy, you know?
  Quoted Text Here  
Quite likely you have the point motor mounted too far one way - ie, off-center. Assuming they/it is below baseboard, have someone hold the motor in the center position and then look at the point/tie bar and make sure it (the pointsd) is sitting equidistant to both stock rails.
If you haven't got a second person then shim between point blades and stock rails and adjust the point motor so the operating pin is centered between the solenoids.
Greg.P.

On Sun, 25 Jul 2010 15:33:00 +1200, "Greg.Procter"
  Quoted Text Here  
I really don't think so, I have gone to extraordinary lengths to get it aligned correctly.
  Quoted Text Here  
I'll have a go, but I am pretty confident that some motors are just "lazy". Guy

  Quoted Text Here  
An alternative is to push the wire up through the little 'ole and then hold it in place with a spring clip, that way it will stay in place whilst you do a little solo fettling re positioning.

wrote:
  Quoted Text Here  
They arent push pull then depending on which way current going through ?
Just seems curious that you are having trouble with so many, suggests youor doing something strange or bad batch. Where did you get them from ?
Cheers, Simon

  Quoted Text Here  
Bad batch I had not considered. They came from Hattons and yes they were a job lot. Guy

wrote:
  Quoted Text Here  
Hattons ;-) Fingers quiver above keyboard - but dare not comment cept wont touch with .....
Cheers, Simon

  Quoted Text Here  
No, the pole piece is just soft iron and will get pulled to whichever end is energised regardless of the way the current is applied (or if ac is used to energise it).
Jeff

  Quoted Text Here  
The armature is soft unmagnetized iron and the coils each drag the iron armature in to the end they are situated at. Kato is probably the only manufacurer doing single coil motors which push or pull a magnet depending on current polarity.
A problem with using DC (CDU) is that the soft iron core can get magnetized if power is applied for more than a fraction of a second - luckily, throwing the turnout the other way reverses the process.
  Quoted Text Here  
Greg.P.

  Quoted Text Here  
I thought that one of the properties of soft iron is that it doesn't retain magnetism after the electromagnetic field is removed ie at room temperature and above the magnetic domains return to a random pattern unlike in steel where the impurities such as carbon atoms prevent the domains from returning to a random pattern after they have been aligned by an electromagnetic field.
Alan

wrote:
  Quoted Text Here  
I have my doubts that Peco point motor armatures are pure iron :-)

  Quoted Text Here  
That's all you should get with a CDU.
That's the point of using a CDU, a far bigger wallop that the power supply could supply by itself, for a very short period.
MBQ