Peco point motors 2: The Sequel

But you havent told us how you are getting on !

Cheers, Simon

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

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]

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

So they try to close point when should be opening it.

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

Probably a mechanical problem - coils out of alignment or something like that causing friction on the armature.

If you mean DCC Concepts of Perth then yes, his UK distributor is Bromsgrove Models.

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.

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.

I really don't think so, I have gone to extraordinary lengths to get it aligned correctly.

I'll have a go, but I am pretty confident that some motors are just "lazy". Guy

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

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

Hattons ;-) Fingers quiver above keyboard - but dare not comment cept wont touch with .....

Cheers, Simon

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

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.

Greg.P.

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

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

Up the input voltage to the CDU and increase the capacitance.

MBQ