Points causing overload.....

[dude2112]

I am now in the world of learning the correct usage of DCC, any help welcome. At the moment I am using the Select controller and when I switch points from lets call them track A too track B I get an overload. I thought the point was that I am talking too

 

the trains not the track or do I need to put the little horseshoe clips on all my points now....?

[Gregd99]

perhaps you can describe what an "overload"is in a bit of detail.

 

are you using point decoders or manually operating.

 

if using decoders then try operating the points by hand. does the issue still occur?

[dude2112]

Hi Greg, I am switching the points over manually, ( the fist time today in DCC mode ) to take a train from one track too another too move it too my train yard. My select just said OL witch I now know means overload and everything stopped....

[Fishmanoz]

Dude, yes you do need to add DCC point clips, the little horseshoe thingys, to all of your points.

 

Your problem sounds like you have a short in your layout when the points are switched. Mybe you have a reversing loop even? Check the latter simply

 

- is it possible anywhere on your layout to have a train leave that area and arrive back at it going in the other direction?

 

Or have you connected the Select to the track in more than one place? If so, you may have accidentally reversed the polarity

 

at the other connect - read swapped the wires compared to the first connection. You only need one connection if you are using point clips.

 

If neither of those, tell us more. Does it work on each of track A and track B but only not when you are running

 

from one to the other? If so, then the polarity problem as I said, or maybe even a faulty point with a short when thrown.

[Rog RJ]

dude2112 said:

I am now in the world of learning the correct usage of DCC, any help welcome. At the moment I am using the Select controller and when I switch points from lets call them track A too track B I get an overload. I thought the

point was that I am talking too the trains not the track or do I need to put the little horseshoe clips on all my points now....?

I'm assuming you are using the 15Volt dc aux power outlet from the Select to power the point motors. If this is the

case, it explains why you are getting an overload when the points operate. Each point motor takes 3 to 4 amps when operating and the Select only has a 1 amp power supply and can't operate points directly via manual switches.

[dude2112]

Thanks guys, I will check out tomorrow after work.... Gotta go bed now as on shift at 4.30 tamoz.

[Fishmanoz]

Rog, I think dude is telling us he is throwing the points manually, so it's not a point motor overloading his supply, it's a short somewhere when track A is connected to track B via his crossover points.

[dude2112]

Hi guys, this is where the learning curve comes in for me on DCC. I have been told too connect all my separate wires that were going too 1,2,3 & 4 on my 4 ovals on DC too my one DCC supply, is this not correct ?

[Fishmanoz]

It's not wrong to do this, in fact see separate threads on DCC Buses. They will tell you that some advocate connecting nearly e dry section of track back to the controller, while others that only 1 connection is necessary.

 

Putting that aside, your

 

problem is almost certainly that you have a polarity reversal in your connections. Instead of all be A to A and B to B from controller to track, one or more will be A to B. you can check them visually of try disconnecting one at a time until the problem goes

 

away, then swap wires and reconnect. I'd start with the visual then, if still a problem, do the one by one disconnect.

 

The reason you have the problem on DCC is that all track connections are live all the time, unlike DC when the track is only live

 

when you turn up the volts at the controller. If you put in the DCC point clips without fixing the polarity, you will get an immediate overload.

[dude2112]

OK Fish, if I am understanding your post I need too check that all my left track wires go too lets say 'A' and my right too 'B' yes...?

[Fishmanoz]

Sorry to take so long to reply dude, but yes, that's right.

[dude2112]

Cheers mate, will sort out when I am off shift.....

[HooliganHedgehog]

I had a similar problem, so I was advised to get a Capacitor Discharge Unit. I did and this worked for one throw of points without overloading, then a delay of a few seconds before it had charged up enough for the next throw. Not enough power I was told.

 

So I bought a 4 amp power supply. Not a lot better! So now I run my points totally independently of the Select Unit using the old 1 amp power supply which had just been made redundant. Still can't throw two points at the same time, but at least I do not have

 

the long delay whilst the Capacitor Discharge Unit recharges itself.

[poliss]

You should not use a CDU with accessory decoders. They have one built in.

[HooliganHedgehog]

Sorry Poliss I didn't explain, I wasn't using a Decoder, I was switching manually ... which is what I think Dude 2112 is doing.

[poliss]

My post was for those who might think of using a CDU with an accessory decoder Hooligan.

It's best to use a seperate power supply if you're using passing contact switches to power point motors.

[walkingthedog]

You should have no problem changing two points, even three, with a CDU. Make sure it's a good one, not in a fancy plastic box, just a circuit board with a few component on it.

[Flashbang]

Hi

The replies seem to be getting away from what the topic started off with.

The problem posted originally seems to me to be most likely a short circuit, caused by incorrect wiring of two loops of track that are connected by across over pair of

 

points. The short only occurring when the cross-over two points are set for the cross-over direction. If as I suspect, and no Electro point clips are fitted, but the separate loops of track have their own feeds, then one set (or more) of these feed wires needs

 

swapping around.

 

If the problem is to do with the actual operation of point motor this hasn't been made clear!

 

To clear up any other issues...

For DCC point motor operation, a point accessory decoder is required. No CDU is need, nor

 

can it be fitted. Hornby decoders have them built in.

 

For conventional passing contact lever or other suitable switch operation using the 15 volt dc auxiliary output from a Select or an Elite will not work very well.

15 volts dc is rather on the

 

low side. However assuming the wiring is in the correct wire size it will operate one solenoid motor at a time, but the 1.0Amp PSU provided with the Select will not sustain the load placed upon it and the Select will momentarily fail. Hence the recommendation

 

to increase the PSU to the 4.0Amp one if this power source is to be used.

 

If dc is the chosen power source it really needs to be around at 19 to 22 volts dc. Without a CDU the dc PSU should ideally be able to deliver around 3.0Amp or more current is

 

better.

 

If ac is used the voltage can be around 16 volts ac. Without a CDU at least a 1.0Amp supply is really needed or greater current.

 

However, if you add a CDU (Not really recommended with Hornby R044 Black passing contact levers - see below))

 

the current from an ac power supply can be as low as 250milliamp (1/4Amp). It will just take the CDU a little longer to reach fully charged state.

 

Now the techie bit... Using an ac supply increases the output volts available from the CDU to

 

1.4 times the ac RMS input voltage. e.g. 16 volts ac will deliver approx 22.4 volts dc output from a CDU. The capacitors in the CDU charging to the ac Peak voltage which is 1.4 time the RMS voltage.

This is why feeding 15 volts dc (Select or Elite aux.

 

output) into a CDU will only provide approx 14.4 volts out! There is a small loss due to the diode(s) in the CDU and it will not operate two motors simultaneously. Ideally feed a CDU with ac volts and between 16 to 24 volts depending on the rated input of

 

the CDU.

 

Using the R044 designed in the 1950 or early 60s with a CDU causes some problems due to the way the R044 operates internally. As the lever is moved from rest its first internal contact makes connection to the motor coils, but the coil is the

 

one that's already in the existing points position. As the lever moves further across the frame the first connection is broken and no connection is made until the lever almost reaches fully over, then it makes connection to the other second contact and the

 

other motor coil and this allows the motor to throw over. Finally the lever reaches the fully over position and all contacts are broken again.

This is why you can hear a double Buzz as the lever is moved over!

The problem when using a CDU is that the

 

capacitors in the CDU are discharged into the first coil immediately the lever is moved from rest and the CDU has no time to reach a recharged condition before the second coil is connected, resulting in a failed or partial throw of the points. Holding the

 

lever midway for a couple of seconds will allow time for the CDU to recharge and then be able to operate the motor(s) correctly.

 

Its really time Hornby redesigned the R044 to bring it up to a more appropriate operating method that would be suitable

 

for CDU operation.

 

 

 

 

[Flashbang]

To add.... If you want to see the inside of a R044 and why it makes twice, have a look at http://www.brian-lambert.co.uk/Electrical.htm#Point%20Motor%20Wiring. Just scroll down a little to the item.

[walkingthedog]

Good reply Flashbang but I used to use a CDU with the Hornby levers and never ever had a problem. You just need to switch them quickly, don't hang about pretending they're real point levers in a signal box.

[Fishmanoz]

Agree, great explanation of how to throw points using point motors Flashbang.

 

Just back to dude's problem, he makes it clear back near the start of the thread that he is throwing his points manually, so the problem is one of polarity reversal on

 

one or more of his I think 4 DCC connections to his layout. All he did was to connect a DCC controller to his previously DC layout without checking that the polarity was the same on each. It is not necessary, even if it is desirable, on DC to have all the

 

same as you would only use one of the controllers to move from one loop to another. With DCC it is a problem as all connections to track are live all of the time so the overload occurs as soon as you throw the crossover points. He has yet to fit DCC point

 

clips. If he had, the overload would have occurred the instant he turned on the controller. Also, as he has a connection to each loop, he doesn't need to fit point clips, although I would to improve reliability.

[dude2112]

I'm back, tired but back. I will tomorrow check all my wiring and try it out. As stated, when I used analogue control I had different wiring needs as had train's running in opposite directions so the wiring was too suit. I will get the point clips and

 

actually had too remove some from second hand points when I was DC controlled. I did however save those clips. I have always had the plan too operate my points electronically so when I have sorted out my basics I will sort that also.

I was going to use

 

the accessory links on my DC controller but I now believe you are telling me that the same is not powerful enough on my Elite, is this correct ?

[Flashbang]

I was going to use the accessory links on my DC controller but I now believe you are telling me that the same is not powerful enough on my Elite, is this correct ?

 

Hi

You can use the accessory output on an old dc controller and this will

 

normally be 16 volts ac. This can be fed into a CDU if wished, then onto the point operating levers/switches.

 

Equally you can use the 15 volt dc axillary output on the Elite to feed the points, but its little point (no pun) in using a CDU then as it

 

wont charge to more than the 15 volts dc anyway! But you will with the Elites Aux. supply be able to operate one solenoid motor at a time via a suitable passing contact point lever or a non locking sprung to centre off toggle switch.

 

[dude2112]

Thanks for the help guys, I now have all 4 ovals sorted...

[Fishmanoz]

Great. Glad we could help.