Sodding point motors

I've just spent three hours failing to get one pair of point motors to
work. They work fine off the layout, the points work fine without the
motors, but once the motors are on the points they simply will not
move, despite careful measurement and any amount of adjustment.
Part of it is, of course, using Peco motors, which are shit, but I
can't justify paying the huge cost of using better motors. Or at
least I couldn't, if this experience is anything to go by I will be
able to justify gold plated motors with diamond encrusted labels just
on the basis of saving my sanity.
Guy
Reply to
Just zis Guy, you know?
Loading thread data ...
Servos are cheaper than Peco point motors and much more adjustable. The electronics to drive them doesn't have to cost much depending on your application.
MBQ
Reply to
Man at B&Q
In message , "Just zis Guy, you know?" writes
Hi Guy
If you are not attaching the Peco motors directly to the underside of Peco turnouts, they can be a pain to fix.
A pity then that the other posters to date have not been helpful.
The vital aspect to mounting Peco motors underneath the baseboard is to set the turnout blades to mid position and secure them there with some card packing.
Now position the motor underneath so that the solenoid is in mid-throw and fix the motor - yes, it's not easy to get at the screws!
That should sort it.
Also - you do not mention the power supply you are using for the motors. Solenoid motors operate best when a capacitor discharge unit is used rather than the output direct from a transformer.
If you need more assistance - ask!
Regards
Reply to
Bill Campbell
What frustration!
As Bill Campbell has said the secret is in the capacitor back up.
I used a bank of 3 x 6000 mF (10,000 if you like) capacitors arranged in parallel and applied to the solenoid coil via passing contact switches. The supply taken from the unregulated DC output of almost any old controller.
I operated up to 4 of those crap motors simultaneously and the 60 odd on the system rarely gave trouble that could not be traced back to me!
No other components are needed.
regards
Peter A Montarlot
Reply to
Sailor
Thanks for this. I was drilling pilot holes down form a template overhead so they were correctly positioned, it turns out the problem was the CDU! It worked fine on motors off the layout but the distance from CDU to motors (a bit over 40ft) was too big for the power to transfer. I moved the CDU and hey presto! it works.
And now to the next problem: no power out from the LV102 :-(
I think next time I will go with clockwork...
Guy
Reply to
Just zis Guy, you know?
This will be cheaper than buying the Peco CDUs, but did you need to put any other components in circuit? has a nifty looking circuit diagram, but the capacitance is not huge.
Guy
Reply to
Just zis Guy, you know?
Guy,
It sounds like the problem is your forty feet of wiring between the CDU and the point motor. :-) Solenoid motors require a fairly hefty current when operating and if your long length of wire is not man enough to carry this current, then you wont get any operation. Moving the CDU closer to the point motor and, therefore, shortening the length of wire, improves the situation. But for good solenoid motor operation you should use quite large gauge wire to avoid voltage drop/current limiting.
Jim.
Reply to
Jim Guthrie
Yes, voltage drop is a problem with low voltage supplies of course - I have a 4.0mm^2 bus round the layout with 2.5mm^2 distributors and 1.0mm^2 drops, plus additional thin drops at both ends of points and at any other dodgy places, but of course I hadn't scaled the turnout power for the larger layout because turnouts are always close to the frames - except they aren't, if the power supply is 40ft away! I think I will give each frame a CDU of its own.
Guy
Reply to
Just zis Guy, you know?
To save wire the sensible thing is to put points that are close together on the same CDU. However if your throwing them at the same time for a route then tis better to put them on different CDU's. Found this to be important with DCC points controllers having inbuilt CDU's when using computer control to throw points with minimum delay.
Cheers, Simon
Reply to
simon
No, nothing else. Simply conect the positives of each electrolytic and solder on the the positve feed and repeat for the negative. I used peco and hornby passing contact levers to switch the positive line and used the negative as common. I also used make when operated switches and push button types ( whatever I could get on ebay). To take advantage of the ac ripple on the unstabilised supply you could fit a diode (5 amp size) into the capacitor feed but that means taking the switch feed from the capacitors or at least the capacitor side of the diode.
My system covered 28 ft by 7ft and had only the one capacitor bank.
(Hint 50+ years in electronics and control).
Regards
Peter A
Reply to
Sailor
snipped-for-privacy@4ax.com...
The MERG controllers will reliably throw two points at once. It depends upon the CDU.
MBQ
Reply to
Man at B&Q
Generally, CDUs are fired intermittently so you can charge them at a slower rate (i.e. taking longer) than you want them to discharge. You should always have some form of current limit on the charging side to be kinder to both the capacitors and the power supply. You can then even connect the CDU input to a DCC power bus, something you should never do with raw solenoids.
It's worth using as higher voltage as possible since the energy stored in the capacitor (and thus available to fire the point motor) varies with the square of the voltage, but only directly with the capacitance. I would use more than 2000uF, however.
MBQ
Reply to
Man at B&Q
The MERG controllers will reliably throw two points at once. It depends upon the CDU.
MBQ
was thinking of routes with more than 2 - need at least 2 for a crossover where you may want to use just one lever.
cheers, Simon
Reply to
simon
I went through that. I found that my controller wouldn't give enough current to move both motors at once.
Then I found, it is just as good to have a stiff wire to the edge of the baseboard (about 1') to operate the point.
Reply to
James Goode
I've got a CML DAC10 DCC stationary decoder which is programmable to vary length of pulse and recharge time between throws. So setting a route with points you see them move one after another. It has inputs which I have used to set routes from a mimic diagram. See
formatting link
for more details.
Chris
Reply to
Chris
I visit the local house demolition/recycling yard(s) for old (not that old) mains cable. Odd short (for a house) lengths make good common return wiring. Here in NZ most flexible/multi-strand wiring is in figure 8 plastic moulding which can easily be split so it no longer looks like mains.
Greg.P.
Reply to
Greg.Procter
I make simple diode/resistor/capacitor CDUs that cost very little and so can be added to every turnout pushbutton. The cost of electronics in the 1960s-70s was such that most of us could only afford one CDU but time and prices has moved on. These very basic CDUs take up to a second to recharge, but how often/quickly does one need to repeat throwing points in the same direction???
Regards, Greg.P.
Reply to
Greg.Procter
.... Snip
I dont think its a need, but child enjoys repeated throwing points till they insist on resting.
Cheers, Simon
Reply to
simon

Site Timeline

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.