9v supply to Tortoise question.

[The Sligo Rover]

Help again please, I need to run a cable from my 9v output to my Tortoise point motor. I have searched to try and find what cable size I should use but cannot find any reference to it anywhere. So I have decided to ask the experts.

[The Sligo Rover]

The output quoted on it is 12.0V, 2.0A 24.0W.

[Brian]

Hi
Your supply is able to provide up to 2.0Amps at 12 volts DC
What you connect onto this supply will only consume only what it needs to operate. So for an example.. A single LED with 1K series resistor will consume 0.01Amp (10 milliamp) That leaves 1990 Milliamps still free to be used.
Connect a Tortoise motor and that will consume around 0.004Amp running and approx. 0.016 stalled (4 milliamp running 16ma stalled)

The 2.0Amp power supply is able to operate in a stalled condition well over 100 Tortoise motors (0.016 x 100 = 1.6Amp)

Wire size from the the supply to everything to be connected 16/0.2mm (3Amp rated)
From each Tortoise operation switch (DPDT) to each Tortoise 7/0.2mm (1.4Amp rated)
You could even use Burglar Alarm cable which has six cores of 7/0.2 inside to each Tortoise motor and then two cores are used for the Tortoise motors operation two for LED supply feeds from motor contacts to route indication LED Anodes and another core for a continuous positive supply (12v?) to the contacts as the feed. That leaves one core spare.

[Rog (RJ)]

I would use 7/0.2 wire, which should be suitable for your application. You may want to consider fitting a 1 amp fuse close to the output of the power supply, just in case.

[The Sligo Rover]

Thank you Brian & Rog, that is very helpful. Can you give me any more details or advice on how and where I can obtain the necessary fuse bits. I am a bit of a novice on the electrical side of things - but learning all the time.
Thank you again for your help.

[Brian]

Fuse and suitable fuse carrier can be obtained from many electronic style retailers and some specialist hobby shops. Fuse carrier and correct size (length and current rating) Fuse to fit examples http://www.brimal.co.uk/ 1.0Amp or 2.0Amp will be fine. Use "Menu"/"Fuses & Holders" to select.
The major problem with fuses is of course when they blow due at a overload they have to be replaced, so a stock of replacement fuses is needed.

IMO its easier to use a self resetting thermal cut out which simply trips when a overload is present and then self resets once the problem has been removed. An example... https://cpc.farnell.com/unbranded/an-10 ... %20breaker that's a 1.0Amp trip, while this one is a 1.6Amp version which I feel would offer your 2.0Amp supply adequate protection... https://cpc.farnell.com/unbranded/an-16 ... %20breaker

Fuse or circuit breaker its connected into the positive supply line from the Power supply and before anything needed to be connected to the supply.

[The Sligo Rover]

Thank you again for the fuse information.
I have spent most of this afternoon running cables under the baseboard to and from my proposed panel locations,
did not bump my head once for a change and did not need my fleece on in the shed either.
I have Radio Caroline on via the internet all the time when in my shed, great music, no news bulletins and very few ads compared to most commercial stations.

[The Sligo Rover]

A further question please.
The diagram supplied with the Tortoise show the DC supply going to the terminals at the top (1 & 2) of the DPDT switch. I have also seen diagrams showing the DC supply going to the two middle terminals (3 & 4) and while I do not doubt the details supplied with the Tortoise I just wondered what the difference is if any with the DC feed being connected to the different terminals. The DPDT switches I have are just a simple 2 position on/on switch.

[RFS]

The DC supply from the transformer goes to the top two terminals and then joined to the bottom two (top left + bottom right, and top right + bottom left). The feed to the Tortoise motor goes to the middle two terminals of the switch, ie 3 and 4. This is what my Tortoise diagram shows.

See diagram here - http://www.circuitron.com/index_files/I ... 000ins.pdf

[The Sligo Rover]

Thank you RFS, that is the diagram I have. Just wondering why other diagrams I have a copy of are different and why?