Turn-out Wire gouge

Basic electrical and electronics, such as DC/Analog control.
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brober
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Turn-out Wire gouge

Post by brober »

When I set out to build my layout 4 years ago I thought I was being smart and pre-wired some turn-out motors for future connection. I fitted Seep PM1 motors and, naively, soldered short lengths of 7/0.2 wire for future connection on to them. It is not practical, without huge disruption, to get back to change these wires to 16/0.2. Will it be any benefit to make connection to them using 16/0.2 wire, approx 2m long, and leaving the 7/0.2 for the last 250mm? As you can tell I'm not competent in matters electronic so would appreciate any helpful comments. Many thanks.
21C1
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Re: Turn-out Wire gouge

Post by 21C1 »

7/0.2 wire will carry 2A so what is the problem?
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Ironduke
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Re: Turn-out Wire gouge

Post by Ironduke »

Maybe, if you keep the 7/0.2 wires as short as possible. Seep PM1s use a lot of current compared to other brands. A CDU will help as well.
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Rob
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Flashbang
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Re: Turn-out Wire gouge

Post by Flashbang »

Actually, most 7/0.2mm equipment wire is rated at 1.2A to 1.4Amps. :o
The resistance of most solenoid point motors is around 4.0 Ohms - Seeps, Peco PL10, Hornby R8014 etc. Therefore the current flow is around 4Amp instantaneously. Volt drop occurring in wire runs is also an issue where smaller wire sizes are used.
Hence this is why 16/0.2mm is recommended for all solenoid motor wiring as a minimum. Where two motor move together consideration should be given to increasing the common return wire to ideally 32/0.2mm or double up 16/0.2mm
Try and reduce the length of any 7/0,2mm wires to the minimum if you want to ensure 100% operation. Especially with the Seep PM1 to PM4 range as these need every milliamp of power they can get! :D
But someone will come along and say "Well my layouts been working with (enter here .... bell wire, alarm cable, Cat 5 cable and even damp string to suit)!"
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Bufferstop
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Re: Turn-out Wire gouge

Post by Bufferstop »

That's me!, My points and signals are now all mechanical, (I wanted my hobby to be as different from work as possible), but I always used 7/.02 for droppers from the rail where it might be seen, and joined it to 16/.02 as close as I could reach. Never noticed much difference, it's the total resistance in the circuit that matters.
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Ironduke
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Re: Turn-out Wire gouge

Post by Ironduke »

Bufferstop wrote:but I always used 7/.02 for droppers from the rail where it might be seen
Aye but the OP is talking about point motor wiring, not track power.
Flashbang wrote:But someone will come along and say "Well my layouts been working with (enter here .... bell wire, alarm cable, Cat 5 cable and even damp string to suit)!"
I used Cat5 for a few feet on my Kato point motors, but I don't think they use nearly as much current as a SEEP.
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Rob
brober
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Re: Turn-out Wire gouge

Post by brober »

Thanks all for your comments. I suspect I may try with the 16/0.2 connected to the 7/0.2 and see what happens (the turnouts were going to be paired but perhaps keeping them as singles might help. A CDU will be fitted so again this might help. If it fails then they will have to be hand operated. Every day's a school day!
PS I must do my spell checking more closely!
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Flashbang
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Re: Turn-out Wire gouge

Post by Flashbang »

If you have plenty of 7/0.2mm wire to hand, trial doubling up the two feed and the one return wire to a motor. Trying to keep the new wires to as near the same length as the originals ones are. By doubling up all wires you will give the circuit a better "fighting chance" of working correctly every time. (14/0.2mm v 16/0.2mm) :D
Note re CDU; while normally only one is needed for the whole layout, if you're using the Hornby Black R044 passing contact lever the CDU will not work well with these old designed levers. But a CDU is fine with all other operation methods - Peco PL26 levers, (On)-Off-(On) sprung to centre Off toggle switches, Push to make non locking push buttons and even Stud and Probe. Try to feed a CDU ideally from a 16 to 18 volt AC supply, but DC can be used and here 18 to 22 volts DC is the optimum input voltage.
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brober
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Re: Turn-out Wire gouge

Post by brober »

That is a good suggestion Brian, however I will be unable to double up the existing short length pre-fixed 7/0.2 wires. My tracks are run off a PA2 and are fully DCC. I propose to run the turnouts from a DC Bus from a separate power supply through a CDU. The switches will be Single pole SPDT (on-off-on) centrally sprung.
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Re: Turn-out Wire gouge

Post by Peterm »

I made my own cdu with four 4,700uf caps. these shifted up to eight Peco motors at a time through a diode matrix with cat5 wiring. I know it's all theoretically wrong, but I think the cdu had so much grunt that I could have used that bit of wet string that Brian mentioned. :wink:
Pete.
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