Some SUPER basic questions on electrics. Please help!

[richscylla]

Electrics are very new to me and I'm always panicking that I'll electrocute myself or burn down the house! My questions are basic - so basic that I can't find the answer despite much searching. The answer is either so obvious no one has ever had to ask it, or are too afraid to ask for fear of looking like a complete moron! So here we go!!

Question 1:
I'm using a Bachmann EZ Command (because that's what I could get very cheaply on eBay - although I do have my eye on an NCE Power Cab if I can get everything working properly! It has a connector like this:



My question is... how do I connect my controller to my DCC bus wires (3.3mm overall diameter wire rated at 21A). Also, I assume that the other end just goes into a terminal block?

My second question is similar...
I'm wiring up my SEEP P1 point motors, and after a lot of research and confusion I think I understand where everything goes. A and B go to the switch. C goes to 0v (negative on the DC), the circuit is completed by the positive DC to the centre point on the switch. Then D and E go to the DCC bus wire and F goes to the frog to supply power to the track in the correct polarity. The thing I don't quite understand is where is the DC power coming from?! I'm looking to set up DC bus wires, as I'm hoping to run signals, platform lights and other non-DCC powered lights on the layout (all controlled from a control panel).

But what powers the DC bus wires? I understand I need an adaptor to turn mains power into safe 12v DC power but what is the best thing to use for that? I see some people say using phone chargers and things like that - but that sounds like dangerous bodging and that scares me! So what is the best thing to use, and again, how does that connect to my bus wires? 

Sorry for my ignorance!

PLEASE HELP!

[Ron Solly]

You could spend some time reading this site

http://brian-lambert.co.uk/DCC.html     and this for basic DC  help   http://brian-lambert.co.uk/Electrical.html

 

 

now regarding your photo, that is so basic it plugs into rails under Setrack  bit you could cut the plug off and join the two wires to you DCC bus

 

More help can be read here  http://www.members.optusnet.com.au/nswmn2/DCC.htm and/or http://www.members.optusnet.com.au/nswmn/dcc_articles.htm

[Pete the Elaner]

I would have thought that the voltage from a phone charger would be too low to throw a Seep motor.

I have heard of people using laptop chargers.

Seep motors respond very well to being powered from a CDU. These either work only with AC or are not bothered if the supply is AC or DC. I use a transformer but if you prefer to have something ready-made, then perhaps use the 16v AC output from a cased controller?

This leaves you with AC rather than DC, but it is easier to rectify AC to DC than it is to invert DC to AC.

[Joseph_Pestell]

I would have thought that the voltage from a phone charger would be too low to throw a Seep motor.

I have heard of people using laptop chargers.

Seep motors respond very well to being powered from a CDU. These either work only with AC or are not bothered if the supply is AC or DC. I use a transformer but if you prefer to have something ready-made, then perhaps use the 16v AC output from a cased controller?

This leaves you with AC rather than DC, but it is easier to rectify AC to DC than it is to invert DC to AC.

 

Point motors (solenoid type) work just as well on AC as DC.

[Phil S]

You might also lok for WAGO connectors on the Screwfix website - the LEVER type is available in 2,3 and 5 way - and makes cble connections simple and tool-free ... hence I use them a lot as it saves finding a screwfdriver ... also screws work loose  (and are a reason some 13A plugs get hot - if they have screwed connections for the 3 wires that haver not been checked for a long time!)

 

When choosing wiring, keep mains voltages off the layout, -especially if 'ex-mains-type' wiring is used at all for busses etc. - it helps avoids accidents in the future.

 

In the EC area, Switched-Mode-Power-Supplies are now used instead of 'Transformers' to get low voltages from the mains supply - these are much more energy efficient than traditional 50-60Hz mains transformers, and they are much lighter (less copper and laminated iron core) and cheaper to buy and transport. This is why all current railway sets have the 'brick' or 'wall-wart' plug-in power supply... usually outputting DC   (EG Roco 18Vdc out to give 16V dcc on track from their Central controllers like the Z21)

 

You have already chosen your point motors etc, it seems, but FYI, some,like the ESU/Bachmann SwitchPilot Points/Accessory Decoder are powered EITHER from  12**-16Vac, 12**Vdc or TrackDCC (with the 12**-16Vac input being the most powerful, and the 12Vdc the least powerful option - assuming dcc track voltage is 14-16Vdcc (which gives about 12Vdc at loco motors).  The Lenz LS150 ONLY works with 12**-16Vac external power NO DC!!, but Capacitor Discharge Units like theTrain Tech Modules charge over a few seconds from the DCC bus.   [**Note 12Vac/dc is adequate for the Switchpilot for semaphore or colour light signals, or efficient point motors - but not standard Peco or even a Roco Uncoupler 8-) ]

 

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[Pete the Elaner]

Point motors (solenoid type) work just as well on AC as DC.

I agree that they should, but they don't always.

I helped a friend wire up a layout a while back & we tested some Seep motors on 16v AC. They made a half hearted attempt at moving but none were actually throwing.

We connected up a CDU (which we were planning to fit anyway) & they worked nicely. They still do 5 years on.

[WIMorrison]

If they don’t switch on 16v ac it is simply that your power supply was/is too weak and this is also suggested by you needing to use CDU to make them work, a large enough power supply will change those motors without issue - too small and you get exactly the issue you describe.

[Ron Solly]

If they don’t switch on 16v ac it is simply that your power supply was/is too weak and this is also suggested by you needing to use CDU to make them work, a large enough power supply will change those motors without issue - too small and you get exactly the issue you describe.

Yes using AC only, the power supply has to be a minimum of 2 amps - preferably 3 amps.  That is why a CDU is perfect, the AC can be around 1Amp & let the capacitors do the work .

[10000]

I would have thought that the voltage from a phone charger would be too low to throw a Seep motor.

I have heard of people using laptop chargers.

Seep motors respond very well to being powered from a CDU. These either work only with AC or are not bothered if the supply is AC or DC. I use a transformer but if you prefer to have something ready-made, then perhaps use the 16v AC output from a cased controller?

This leaves you with AC rather than DC, but it is easier to rectify AC to DC than it is to invert DC to AC.

 

Older phones may have had some that gave out 12v but all the phones I've had in the last 8-10 years have been 5v.

[Pete the Elaner]

Yes using AC only, the power supply has to be a minimum of 2 amps - preferably 3 amps.  That is why a CDU is perfect, the AC can be around 1Amp & let the capacitors do the work .

Without going into the technicalities of how a CDU works (which would probably be OTT for this thread), that is an excellent answer.

Once you have a CDU in place, a larger supply won't give you any benefit.

[WIMorrison]

On the last layout I used an 18v 95w laptop charger - worked a treat and I didn’t need any CDUs

[WIMorrison]

Without going into the technicalities of how a CDU works (which would probably be OTT for this thread), that is an excellent answer.

Once you have a CDU in place, a larger supply won't give you any benefit.

But it will hurt your fingers if you put them across it when it is charged - much more so that an appropriately sized power supply

[Pete the Elaner]

When using a CDU, it is always advisable to throw a point after you have turned the power off.

 

I see that I really am now going to have to explain how & why a CDU works..

 

A solenoid is just a coil. Applying a current creates a magnetic field, which is what we want to throw the point motor. The CHANGING magnetic field generates a voltage, which is in the opposite direction to the current being applied.

If you use a transformer to supply the voltage, this will also oppose the change in current. So it supplies a voltage 1 way but the change in current generates a voltage the other way. If the process was 100% efficient, these would cancel each other out,

 

When you re-open the circuit, the sudden drop in current causes the solenoid to generate a voltage. If anyone uses a probe & stud, then you will see this as a spark when you release the probe. You will also get a lot of pitting on both stud & probe. It is also the reason why you can't use cheap push-button switches.

 

If the current is supplied by a capacitor, as in the case of a CDU or a smoothed power supply, then this changes matters.

A capacitor simply stores charge,rather like a battery but it has a much lower internal resistance. This gives the kick you want to throw the point. The capacitor discharges itself very quickly. If designed correctly, it will charge with a small current so that after the initial kick which throws the point, this is the only current remaining. It will therefore not burn the point motor out is you leave the connection closed for too long.

Because the current flowing through the coil is small, so the collapsing magnetic field is very weak. Because the collapsing magnetic field is weak, the generated voltage is weak so you get a tiny spark when you like the probe again rather than a bigger one if the CDU was not there.

This means you get a lot less pitting on your probe & studs.

You can also get away with small push button switches because you are not continually burning out the contacts with a big arc each time you release them.

 

A big transformer is therefore not a nice solution. A smoothed DC power supply like one for a laptop is much better. Have you ever noticed that when you turn it off, you can see the power light slowly fade away? This is the capacitor(s) discharging.

 

I am not sure if that is of any help to the original question though.

[WIMorrison]

Hopefully explaining this makes you feel better though

 

If you read a couple of posts before your one you will see that a laptop power supply has already been suggested ...

[Pete the Elaner]

Hopefully explaining this makes you feel better though

 

If you read a couple of posts before your one you will see that a laptop power supply has already been suggested ...

Haha. Yes & yes.

It was me who suggested the laptop charger. 

[richscylla]

Thanks for everyone's input!

I have also been told an old analogue Hornby controller with accessory connectors via a CDU would also work, and I think I have one lying around somewhere!

Rich

[Crosland]

I like the toilet analogy

 

Powering solenoids directly is like trying to flush the toilet using a hose connected to the nearest cold tap. You probably need a four inch hose connected to the nearest fire hydrant.

 

Using CDU is like letting the cistern fill up and then releasing all the water in one go by operating the flush handle.

[Penrhos1920]

Just remember that DCC is just 2 wires - not more, not less

[Ron Solly]

some more reading matter re CDU, etc

 

http://www.talkingelectronics.com/projects/CDU%20-%20overview/CDU%20-%20Overview.html

 

this is found by clicking on   CDU-2

http://www.talkingelectronics.com/projects/CDU-2/CDU-2.html