(LGB point motors and switches) Didnt know where to post this...so....

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steves

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Sorry and I am sure this has been asked lots of times but I just can't find a post about it as yet.

I have picked up some Electric operated LGB points. never having used this sort of points before it has just 2 connectors and seeems to be rated at 14v - 18v. I know NOTHING about these as previously I have only ever had 00 gauge points.

What do I need to use to power these and switch these points, either the proper equipment or preferably what I can get away with using, for example a 12V battery or laptop power supply or what ever and a couple of manual switches and how to wire them up?

Many thanks and sorry for the likely repeat
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Title edited by Mods.
 
Re:Didnt know where to post this...so....

Steve, "what you can get away with" sounds like just my sort of fix! The point motor itself will usually run quite happily on 12v d.c., momentary switched (change-over), that is how I run mine. However that is not the way that LGB prefer to run them, they use a.c. with a rectifier in circuit and a fancy switch box. That's too complicated for my poor little brain, hence the simple method.
 
Re:Didnt know where to post this...so....

I'm sure it's answered somewhere on here, but in case you don't find it here's the basics.

The point motors need a short burst of DC power, one polarity changes them one way, the other polarity the other way.

You will need a two way centre off momentary switch for each point (or series of points if operated as, say, a pair on a crossover). These are often described as (ON) OFF (ON) switches.
If you use an AC supply you only need a single pole switch but you need a couple of diodes as well, if you use a DC supply you'll need a double pole switch. Typically 18V nominal AC or 12V nominal DC supplies of 10VA or more are O.K. Just try it and see if an existing supply works. If operation is a bit iffy you could try thicker wiring to minimise volt drop as an alternative to a higher voltage supply.

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Re:Didnt know where to post this...so....

The point motors need a pulse of reversable DC supply to throw the point one way or t'other. LGB does this using an AC supply half-wave rectified by diodes built into the switch box.

<edit> Ah good - other simultaneous posts. I was hoping Neil would respond with one of his useful diagrams </edit>
 
Re:Didnt know where to post this...so....

I use a cheap capacitor discharge unit to operate mine, through momentary dpdt switches wired as reversing switches. You can use a 12-16v ac supply to the cdu and it has the effect of 'upping the oomph'. Reliable point switching and no worry of a burnt out motor, been running them like this for over a year now with no adverse effects at all. Can even switch upto 4 points simultaneously. :D
 
Re:Didnt know where to post this...so....

Hi Steve
The tech has been discribed perfectly by the clever ones but just in case you are like me
If you take the cover off of you points motor you will see unlike Hornby etc which have a back and forth AC solinoid and runs off the 16v accessory terminals, LGB has an electric motor which like the motor in a loco runs one way or the other depending on which way you connect the wires the moter is stoped from turning full circle by little luggs or stops. You need a short burst of dc power 12v---- 16v to change the point oneway or tuther constant power will burn it out so just a short burst..

Tony
 
Re:Didnt know where to post this...so....

Right I reckon thats as clear as mud for me now

So I have a choice of AC or DC, 12 V to about 18V, single pole or double pole and slide switches and rocker switches, and 3 position or is that 2 position too? :( It would appear there are more ways to skin a point than I had given credit for.

I like saving money, so if there is a safe option without the chance of burning out motors that sounds like the one I need, i think? :(

I really don't know now, and there was me thinking the instructions were confusing, lol. :) I do understand each option, I just dont understand which is the "best" option as I don't know the risks or costs involved....
 
Re:Didnt know where to post this...so....

If you use a.c. you MUST have a rectifier in the circuit or the motor will just buzz.
 
Re:Didnt know where to post this...so....

bobg said:
If you use a.c. you MUST have a rectifier in the circuit or the motor will just buzz.
Click to expand...

I may not understand this correctly, in fact no, I definately don't understand this correctly, but doesn't a rectifier turn AC to DC? But I do think someone said about using a half wave retifier, which I have never heard of, but it sounds like it just removes one side of the AC giving you a fluctuating DC or something, damn I don't get this? (you guessed it, I am not an electrician just yet l ;) )
 
Re:Didnt know where to post this...so....

Forget the a.c. and plump for a d.c. supply, that is less confusing, only two wires, which are changed over by your (on) off (on) switch.
 
Re:Didnt know where to post this...so....

bobg said:
Forget the a.c. and plump for a d.c. supply, that is less confusing, only two wires, which are changed over by your (on) off (on) switch.
Click to expand...

Now that sounds simple enough to me, even I can understand that, thank you :)

How easy is it to burn those motors out? Everyone says "a short burst" but just how long is a short burst? A millisecond, 10 seconds?
 
Re:Didnt know where to post this...so....

One short press of the button (second) will throw your switch. If you keep pressing (for maybe seven or eight seconds)without switching polarity it could burn out - particularly if point is obstructed. Don't ask how I know:rolf:

But seriously, a momentary switch with some form of polaity reversal works absolutely fine:thumbup:
 
Re:Didnt know where to post this...so....

ALL

You lot are great, soooooooo much wealth of knowledge on here its incredible. :D

I think I know where to go with this now, any problems and unfortunately you can be assured, I will be back (heard that somewhere before ;) )
 
Re:Didnt know where to post this...so....

Maybe it's just me but if your confused about how it works and how to use the referenced work-arounds and worry about burning out the motors (not cheap) then just stump up and buy the LGB switch box? it's not as expensive as burning out a point motor and you will be able to run four points individually or gang up to eight from one box. You dont have to worry about how or why it works it just will! I'm not being smart or plugging LGB it just seems at this point until your knowledge of LGB and the weird electronics used at times would be more cost effective?
 
Re:Didnt know where to post this...so....

As I think I've said before, I use a venerable Scalextric transformer, a dpdt switch for direction and a non-locking push-to-make switch to actuate the points. This system will happily operate a crossover. Switches from Maplins, usual disclaimer.
 
Re:Didnt know where to post this...so....

I think that lot should have confused Steves sufficiently!
Steves - LGB expect you to use an AC supply (say 12 - 18V). Thier switch box does the clever 'half rectification' work so you dont have to think about it. Thier switch box needs two wires connecting to it for the AC input and two wires to the point motor. It is as simple as that.
Sure - there are many ways to achieve the above - some are a bit cheaper, some are not. But if your begining and not too sure about electrics - Keep it simple.
 
Re:Didnt know where to post this...so....

Just an idea here for someone else to try except for myself. Have a look into using a cdu, it turns the ac into dc for you, and saves a 'burst' of current to operate the point safely. Even if you do hold the switch in one position, no damage can occur to the motor as the cdu has discharged immediately after the switch contacts closed.
It is as simple as it gets; place the cdu between the supply and the switch, wire the switch (centre off momentary dpdt) as a reversing switch, and wire that straight to the point. It is safe as long as it is not wired into a dcc system that controls points.
 
Re:Didnt know where to post this...so....

The thing here is I dont have a transformer of any type at the moment as I am live steam only at this time. It will change to electric as well at some point, but not just yet. Does this change what transformer I should buy?

Who ever said this will confuse me was bang on, I just saw an 18VAC transformer for £150 and the point box for around £70 something, so £220 to change a set of points, I would rather stand up every now and again, lol :rolf: There has just got to be better options than that, and I dont even mind the point box at £70, even though I think its a complete rip off, but the transformer, you have got to be kidding me. Laptop transformers although DC can be up to around 8Amp and I can get some of them FOC :)

Maybe I should sell the motors and just rig up some good old fashioned bellcranks and wire and do them manually, lol :(
 
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