How do electric points work?

Sleeping Signalman said:
Hi, I'm using 22v DC.
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Come to think of it, this might be why your points aren't working?

You need an AC supply.

What equipment are you using to operate your point motors?

Part numbers of the boxes would help me here.

Take a look at Alan's reply #2 to this thread and compare with the diagram he has posted....
 
I really don't want to confuse people any further but you DON'T need A.C. Mine work very adequately on around 14v D.C. with dual pole switches. The crossover of polarity is all that is required, and that is achieved by the DPDT centre-weighted switch. Push up (in my case) for one direction and down for the other.

If you use A.C. you do need the diodes to change the polarity. Always seemed a crackpot way of doing things to me but then I studied vehicle electrics . . . . . . (no return. nuff sed!)
 
bobg said:
I really don't want to confuse people any further but you DON'T need A.C. Mine work very adequately on around 14v D.C. with dual pole switches. The crossover of polarity is all that is required, and that is achieved by the DPDT centre-weighted switch. Push up (in my case) for one direction and down for the other.

If you use A.C. you do need the diodes to change the polarity. Always seemed a crackpot way of doing things to me but then I studied vehicle electrics . . . . . . (no return. nuff sed!)
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I totally agree Bob, but I'm trying to second guess Sleeping Signalman's response.

I haven't got all the info I need, but if he is using LGB kit from a DC supply, this 'could' be the cause of his problem.

I used to man a technical support help desk, so I know how hard it is to get the correct information on a problem from the customer.

Always ask the stupid questions first....
 
Yeah, I appreciate that Giz. It's one of these "nothing is obvious" kind of problems, which is why I think it's much easier to understand in D.C., at least you've got a straight circuit to follow to the point of crossover.
 
bobg said:
Yeah, I appreciate that Giz. It's one of these "nothing is obvious" kind of problems, which is why I think it's much easier to understand in D.C., at least you've got a straight circuit to follow to the point of crossover.
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Like it! - Read it again.

A bit like parallel lines never meet.. Unless you bend one, or both of them!!
;) :D ;D
 
Gizzy said:
I guess you are using a DPDT switch then to power the point motor if you are using 22 V DC.
Normally you would use an AC supply for points.

Is there anything in the point tie bar mechanism stopping the blades operating?

Also, are you sure you are actually getting at the end of the cabling to your point motor? Measure and check/replace the cabling if not....
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Correct Im using a DPDT momentary toggle.
I am not getting a 'snap' on ANY of the 8 points, they all take about 1-2 seconds to change.
All change completely and correctly - ie no dirt blocking movement.
I'm using a non LGB transformer that only has DC output (without opening it and bypassing the diode bridge)

As for voltage actually at the motor, I'll check, but it will be a few days.


Regards
 
I've been using a 12v Scalextric rectified transformer for mine before I went DCC and again now I've gone over to battery. I've just installed a CDU (which I'd used previously on my 00 layout) - the CDU isn't essential as it switched up to two motors OK from the 12v supply previously - but as I had the CDU knocking around I decided to give it a bit more oomph. They now click over quite smartly.

Rik
 
ge_rik said:
I've been using a 12v Scalextric rectified transformer for mine before I went DCC and again now I've gone over to battery. I've just installed a CDU (which I'd used previously on my 00 layout) - the CDU isn't essential as it switched up to two motors OK from the 12v supply previously - but as I had the CDU knocking around I decided to give it a bit more oomph. They now click over quite smartly.

Rik
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I use a CDU too. It allows route switching, so far it throws 5 motors at the same time faultlessly.
 
It's occurred to me (at about three o'clock in the morning!) that a possible cause for slow motion point switching might be resistance in the wiring between control box and point motor. I've always used 13amp mains ring main twin and earth cable out in the garden for track feeds and also for the feeds to point motors and experienced no appreciable loss in voltage. What gauge of cable are you using over what distances?

Rik
 
Sleeping Signalman said:
I am not getting a 'snap' on ANY of the 8 points, they all take about 1-2 seconds to change.
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What point motors do you have? Are they slow acting motors, e.g. tortoise?
 
3Valve said:
Don't believe all this stuff on here. It's all done by magic :D :D
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This must be true, because we all know that if the "magic smoke" gets out of the motor then it stops working.... ;)

Jon.
 
Sleeping Signalman said:
Correct Im using a DPDT momentary toggle.
I am not getting a 'snap' on ANY of the 8 points, they all take about 1-2 seconds to change.
All change completely and correctly - ie no dirt blocking movement.
I'm using a non LGB transformer that only has DC output (without opening it and bypassing the diode bridge)

As for voltage actually at the motor, I'll check, but it will be a few days.


Regards
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Sounds like a capacitance/resistance effect, possibly caused by the cabling?

Also, what is the current rating of your (non LGB) transformer. It might not have enough grunt!

Thicker wiring may help, or maybe one of your connections isn't quite tight....
 
Gizzy said:
Sounds like a capacitance/resistance effect, possibly caused by the cabling?

Also, what is the current rating of your (non LGB) transformer. It might not have enough grunt!

Thicker wiring may help, or maybe one of your connections isn't quite tight....
Click to expand...
 
I use 24v AC and thick wire, voltage drop is a problem as the ones furthest away are the ones that usually give problems...
 
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