[B B Beyer]

I'm using the 15 V DC analogue accessory power supply on the Hornby Select unit to power a Hornby R0814 point motor, controlled with an R044 passing contact switch. The point switching works fine - the only problem is, every time you throw the switch, it kills the track power and control feed and resets the controller, which goes through its "power up" sequence. This makes train control impossible if you throw the point switch. Anyone else experienced this?

 

[Lancashire Fusilier]

Welcome along mate, haven't experienced this personally. What current rating is the 15V DC output as it sounds like you are exceeding it when you throw the switch.

 

[B B Beyer]

Hi Fusilier

Actually, I've just found the identical question to mine on the Hornby forum (http://www.hornby.com/forum/forum-thread.html?Ptopic=com.othermedia.hornby.model.board.TopicHandle-L-4&Pthread=com.othermedia.hornby.model.board.Thread-L-8402).

As you suggest, seems to be a transient current overload problem - apparently the Select only gives out 1 A, and according to Rog on the Hornby Forums it cannot normally supply point motors directly.

Rather annoying, since the Hornby website says of the Select: "The transformer also provides power to the 15V DC uncontrolled outlet which can be used as an alternative electrical source for point motors and accessories which are operated in the traditional analogue manner. A larger 4 amp transformer is available for use with the Select unit which will provide additional power to the tracks allowing for more locomotives to be run simultaneously."

...i.e., nothing about needing extra power to operate one lonely point motor!!

 

[Lancashire Fusilier]

Understood. Get your self one of DCC Concepts Masterswitch boards that cost next to nothing and could be powered by the aux DC no worries and will not have any problem running your point motor. The proprietor is on this forum.

 

[Brian Considine]

QUOTE (B B Beyer @ 17 Nov 2008, 00:07) <{POST_SNAPBACK}>I'm using the 15 V DC analogue accessory power supply on the Hornby Select unit to power a Hornby R0814 point motor

Hi & welcome to MRF.

IMHO a better solution would be to power the point from a separate supply such as another transformer or laptop power supply there - I've probably done ourselves out of a Masterswitch sale (we stock them !)

 

[Lancashire Fusilier]

Equally sound advice there too. I was trying to be cheapest robust solution assuming no free power supplies were at hand but it of course would be robust to use another powerpack.

As a matter of interest how much current does it take to power a hornby point?

 

[Richard Johnson]

QUOTE (B B Beyer @ 17 Nov 2008, 08:07) <{POST_SNAPBACK}>I'm using the 15 V DC analogue accessory power supply on the Hornby Select unit to power a Hornby R0814 point motor, controlled with an R044 passing contact switch. The point switching works fine - the only problem is, every time you throw the switch, it kills the track power and control feed and resets the controller, which goes through its "power up" sequence. This makes train control impossible if you throw the point switch. Anyone else experienced this?

*** Hornbys advice is actually very bad.

Their point motor has a peak draw of approximately 4 amps. As with any point motor - Seep, Peco or Hornby, it must NOT use the track power or the same transformer as used for the DCC system.

You need a good separate power supply even when using MASTERswitch... Brian is correct... Current is current (amps), and it cannot come from nowhere.

The ideal and possibly free power supply for these is an old laptop computer supply - 15~18V AT 3~5 amps. They often get thrown in a corner when the laptop dies, so lok/ask around...

All you need to do is cut off the plug where it would be attached to the laptop and use those two wires....

Richard

 

[B B Beyer]

I took the advice of Brian at Euroscalemodels, and obtained a "spare" laptop supply from the IT department at work (they were throwing them out as waste electrical equipment, honestly!). IBM Powerbook supply, 16 V, 4.5 A. Operates the point motors a treat, and doesn't kill the DCC power feed to the track. So I can run my trains and operate a point now without the trains stopping dead! Thanks to all for your advice.

No reply from Hornby yet - I still don't see the point (no pun intended) of the 15V accessory output on the Select if you can't actually operate anything from it!

 

[B B Beyer]

Finally got a response from Hornby:

"Sorry about this but, the AUX output of the SELECT while it will power point motors, can be prone to causing the SELECT to reset. Whether this happens is due to local wiring conditions etc.. see below for a "standard" answer.

Re the resetting of the SELECT..

The SELECT is probably rebooting when attempting to drive the point motor... This is due to the momentary peak current drawn causing a supply line voltage dip which is outside of the SELECT's PSU internal regulator's capability.

We know that when using the Hornby point motor that this can occur.

However, this is dependent on local electrical conditions as to whether the issue appear or not.. i.e. resistance of connections and cable driving the point motor. Generally, increasing the cable length between the point switch and the SELECT can resolves the issue. However, I can't guarantee this as a fix.

You could try increasing the cable length re above.. []if the amount of wire becomes unmanageable (3m?) you may have to consider the following suggestions..

Suggestions in RED are the most effective solution.

1) Use a 1Watt 68ohm resistor in series with point motor for a current limit.

2) Do not allow the momentary (passing) switch to be "on" for more than 1 second?

3) Consider using a separate PSU for to drive the points motors.

The advantage of this solution is that while eliminating any possibility of the SELECT actually re-booting due to current surge, it also means that the SELECT's own power supply is being used only to power the SELECT itself and the locos on the layout.

4) Use a separate Capacitor Discharge Unit (CDU) to drive your point motors. Without going to DCC control this is a good solution. You could use the SELECT AUX power out to drive the CDU. However, a separate power supply is probably more desirable.. see above.

5) Use DCC control with Hornby Point & Accessory Decoder R8247. Note, the Hornby R8247 unit has a built in Capacitor Discharge Unit."

 

[Brian Considine]

QUOTE (B B Beyer @ 9 Dec 2008, 11:30) <{POST_SNAPBACK}>. Generally, increasing the cable length between the point switch and the SELECT can resolves the issue. However, I can't guarantee this as a fix.

- I'm sorry - that's a bit like saying if you car is going too fast with the accelerator buried into the carpet you can slow it down using the brakes !

To be honest, the only real solution will be to power the points (with, or without a CDU) from a separate power supply (as per the suggestions 3/4/5).

 

[80class]

I still can't believe how complicated Hornby have managed to make the entry to their "DCC" world. I wonder how many people have been put off DCC through bad experiences with the select?

Rob

 

[zmil]

QUOTE (B B Beyer @ 9 Dec 2008, 11:30) *
. Generally, increasing the cable length between the point switch and the SELECT can resolves the issue. However, I can't guarantee this as a fix.

I would say its more along the lines of using a longer hose to get more water flow

Perpetual motion and a few free energy devices may help

Regards Zmil

 

[B B Beyer]

"Generally, increasing the cable length between the point switch and the SELECT can resolves the issue"

No, I didn't understand that, either!

 

[Brian Considine]

QUOTE (B B Beyer @ 9 Dec 2008, 22:55) <{POST_SNAPBACK}>"Generally, increasing the cable length between the point switch and the SELECT can resolves the issue"

No, I didn't understand that, either!

Increasing the cable length also increases the resistance therefore the point motor will draw a little less current.

The suggested fix goes against all good wiring practice's - of any voltage.

 

[Richard Johnson]

QUOTE (Brian Considine @ 10 Dec 2008, 11:54) <{POST_SNAPBACK}>Increasing the cable length also increases the resistance therefore the point motor will draw a little less current.

The suggested fix goes against all good wiring practice's - of any voltage.

***Spot on Brian / Zmil:

Apart from the suggestion to use a separate PS or CDU, the hornby advice was so far off reasonable that when I read it last night I simply couldn't think of a reasonable response that didn't just take the P** or would not simply look totally negative... so I refrained.

The effect of a long thin wire or adding a resistor is not only against all common sense - its effect would be to actually reduce the energy that is available to the point motor - the voltage drop from both the resistor and the wire length suggestion (made laughable in thinking that 3m would be a possible useful length of far too thin wire) will simply waste energy.

To make the point motor still throw well at lower current, the added impedance has to be within the point motors coil length so whatever energy available contributes to the magnetic field!

Richard

 

[Kelly88]

why did they not advise to purchace the power supply for the Elite::: this has a higher output ::

ok if you realy wish to go down the route of lenghting the distance between the Select and the Layout/wall socket :: then maybe the local tip would be a sutible place to start

while we are on the subject:: i am given to understand from several sources that it is never advisable to power accesories from the same supply as the controler when using a DCC system no matter what its manufacture ??

rgds
Mike

 

[Richard Johnson]

QUOTE (Mike88 @ 10 Dec 2008, 23:13) <{POST_SNAPBACK}>why did they not advise to purchace the power supply for the Elite::: this has a higher output ::

ok if you realy wish to go down the route of lenghting the distance between the Select and the Layout/wall socket :: then maybe the local tip would be a sutible place to start

while we are on the subject:: i am given to understand from several sources that it is never advisable to power accesories from the same supply as the controler when using a DCC system no matter what its manufacture ??

rgds
Mike

*** The power supply to the DCC unit being utilised should match the DCC units power, so not suggesting the elite PS is correct.

You are however correct in that it is not recommended to use the same PS for controller and accessories. It works sometimes on a smaller layout but as complexity increases, the accessories will cumulativey drain more and more power, and their action can negatively affect the quality of the DCC sugnal on the rails to the point where reliable control is compromised.

Richard

 

[brent.ss]

Hello everybody

I'm just getting into railway modelling so I'm somewhat of a novice but am following the point motor/power supply discussion with interest.

I like the idea of using a laptop as a power supply and wondered if anyone knew if a programme existed or whether something simple could be programmed in (say) Basic that could allow the laptop to act as a keyboard activity switch; must be possible and it would save loads of space and money on not buying a physical switch.

Any ideas out there?

 

[zmil]

Hello and welcome to the Forum Brent

There is software available and some is free to use , but you still need a DCC system with a computer interface and accessory Decoders on the point motors plus a powersupply for them.
You can use a Keyboard or a mouse to switch points or even routes.

Regards

Zmil

 

[Richard Johnson]

***Please do not misunderstand - we are talking of using a laptop power supply without the laptop here - you certainly couldn't use it when attached to the laptop.

As Zmil said, you can certainly use a computer for layout control but you will need (1) computer side, an interface for it & appropriate software (2) layout side, a separate power and or command bus for the DCC accessory decoders as two sets of command centre (computer + controller) can't coexist on one bus UNLESS the computer is using the DCC system as the booster interface.

In the end it probably certainly won't save either money or space - but its a very valid option if you are comfortable with the software and like the idea of using a computer for control as many do.

Richard