RR_Mel OK. Go ahead and redo your measurements on the track. Remember you are chacking the difference between the rails and the reference voltage at the booster under load.
OK. Go ahead and redo your measurements on the track. Remember you are chacking the difference between the rails and the reference voltage at the booster under load.
Rich
Alton Junction
You should have about .06 volts loss per 10' of track. Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
OK. Go ahead and redo your measurements on the track. Remember you are chacking the difference between the rails and the reference voltage at the booster under load. Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
RR_Mel No, the wires between the booster and the buss.
No, the wires between the booster and the buss.
No, the wires between the booster and the buss. Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California
RR_Mel .34 volts. What size wire and how long.
.34 volts. What size wire and how long.
The feeders are 20 gauge solid copper wire, 12 to 18 inches long, max. The feeders in question are about 12 inches from the bus to the rails.
richhotrainSo, just run another pair of 14 gauge bus wires from the booster to the other end of the existing bus wires?
that's the simplest thing that will make things better.
richhotrainOK, what I did was to measure voltage at the booster output which was 14.25 volts. Then, I connected the 1156 automotive bulb to the booster output at the same point and measured voltage under load which was 12.78 volts.
power supply Voltage rating is at some current. that's why you'll see a 9V wall wart outputing 11V. but at it's rated current (e.g. 0.5A) it should be 9V.
but we don't know what Vpk-pk is based on the 12.8V measurement. so it may be spot on.
the 12.8V is the reference. presumably there's not much wire and not much difference in voltage where the booster connects to the track
you only care about loaded voltage values.
greg - Philadelphia & Reading / Reading
.34 volts. What size wire and how long. Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California
At the point of the booster, the voltage under load is 12.78 volts. The voltage under load directly at the point of the first feeder drop is 12.44 volts. That first feeder drop is about 5' from the booster output port.
I don’t think it matters but mark the spot with the measurement for reference later if needed. Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
RR_Mel You really don’t care about the unloaded voltage only the voltage under load.
You really don’t care about the unloaded voltage only the voltage under load.
You really don’t care about the unloaded voltage only the voltage under load. Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
RR_Mel Something isn’t right, the voltage at the booster is the reference voltage for measurements on your mainline.
Something isn’t right, the voltage at the booster is the reference voltage for measurements on your mainline.
RR_Mel You need to remeasure the rails where the buss connects to the mainline rails. Note the difference between the measurements under load at the booster and the buss. Then redo the rest of your measurements, you are looking for the difference under load of your test points.
You need to remeasure the rails where the buss connects to the mainline rails. Note the difference between the measurements under load at the booster and the buss. Then redo the rest of your measurements, you are looking for the difference under load of your test points.
So, now, I should measure voltage on the rails where the bus connects to the mainline rails? With and without load?
Something isn’t right, the voltage at the booster is the reference voltage for measurements on your mainline. You need to remeasure the rails where the buss connects to the mainline rails. Note the difference between the measurements under load at the booster and the buss. Then redo the rest of your measurements, you are looking for the difference from the reference measured at the booster under load at your test points. Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
gregc In order to avoid undoing a lot of what you've done, you could add add a 2nd 14g bus wired from the booster to 10' (?) from the end of your existing bus. this would roughly cut the total bus resistance in half.
In order to avoid undoing a lot of what you've done, you could add add a 2nd 14g bus wired from the booster to 10' (?) from the end of your existing bus. this would roughly cut the total bus resistance in half.
gregc Why not put a booster on either side of the room and use each booster to power half the room? half the track distance?
Why not put a booster on either side of the room and use each booster to power half the room? half the track distance?
rrinker You will of course need a longer control bus cable to connect the two systems, but distributing the boosters to keep the bus runs as short as possible is the way to go. An 80 foot bus run is far too long, even for #12 wire - an according to the post above, that's 80' AFTER splitting it in half,. so 80 feet one way, and 80 feet the other way. If you evenly space the boosters, that gives you 40 feet in each direction from each booster, much more reasonable.
You will of course need a longer control bus cable to connect the two systems, but distributing the boosters to keep the bus runs as short as possible is the way to go. An 80 foot bus run is far too long, even for #12 wire - an according to the post above, that's 80' AFTER splitting it in half,. so 80 feet one way, and 80 feet the other way. If you evenly space the boosters, that gives you 40 feet in each direction from each booster, much more reasonable.
rrinker The drop seems high even for #14 wire - is it a continuous pull, or are the sections of the bus broken and then connected to continue on? If all one pull - are you using IDC connectors to attach the feeders?
The drop seems high even for #14 wire - is it a continuous pull, or are the sections of the bus broken and then connected to continue on? If all one pull - are you using IDC connectors to attach the feeders?
RR_Mel Just curious, what does the voltage measured at the booster or source do with and without load. A lot of loss could be in the booster its self and not in your wiring.
Just curious, what does the voltage measured at the booster or source do with and without load. A lot of loss could be in the booster its self and not in your wiring.
The drop seems high even for #14 wire - is it a continuous pull, or are the sections of the bus broken and then connected to continue on? If all one pull - are you using IDC connectors to attach the feeders? With solid wire, I will almost guarantee the wire is nicked by them and the effective size, especially as you get further from the booster connection, is actually less than #14. Just another reason I prefer stranded in the larger sizes, even though I don't use IDCs.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
RR_Mel Same way you measured the track, the 1156 across the terminals and meter across the bulb.
Same way you measured the track, the 1156 across the terminals and meter across the bulb.
I will do it this afternoon and get back to you. Off now to run errands.
Thanks, Mel, for all of your help.
Same way you measured the track, the 1156 across the terminals and meter across the bulb. Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
gregc 12g wire would be half the resistance (1.6 mOhm/ft) and i'd estimate half the voltage drop. in order to avoid undoing a lot of what you've done, you could add add a 2nd 14g bus wired from the booster to 10' (?) from the end of your existing bus. this would roughly cut the total bus resistance in half. using 12g would be better
12g wire would be half the resistance (1.6 mOhm/ft) and i'd estimate half the voltage drop.
in order to avoid undoing a lot of what you've done, you could add add a 2nd 14g bus wired from the booster to 10' (?) from the end of your existing bus. this would roughly cut the total bus resistance in half. using 12g would be better
gregc looks like you have a separate booster (same size?) for just the reversing sections. why not put a booster on either side of the room and use each booster to power half the room? half the track distance?
looks like you have a separate booster (same size?) for just the reversing sections.
why not put a booster on either side of the room and use each booster to power half the room? half the track distance?
I never considered a 12 gauge bus, since I used 14 gauge on my last layout of similar size without any problems. It would take a lot of work and effort to go 12 gauge so that would not be my first option.
Moving my existing boosters, both NCE 5 amp, around the layout and adding busses would be a better option for me at this point if it comes to that.
How would I measure under load at the booster itself?
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RichI bought the Handy Converter from Stan’s Trains and use it for my calcs. When I used a online electrical calculator it double doubles the loss.Just curious, what does the voltage measured at the booster or source do with and without load. A lot of loss could be in the booster its self and not in your wiring.Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps
0.9V from 12V is 7.5% which seems high (thought 2% was the target)
i calc a resistance of 3.2 mOhm/ft which is consistent for 14g wire.
ATLANTIC CENTRAL I think I would have been inclined to the divide the layout geographicly (east side/west side) rather than by main/secondary trackage and keep wire runs shorter.
I think I would have been inclined to the divide the layout geographicly (east side/west side) rather than by main/secondary trackage and keep wire runs shorter.
The two yards (coach and freight) are part of the same power district as the two mainlines. I have separate power districts on the primary booster for (1) the passenger station and (2) the engine servicing facility.
The mainlines power district is an 80' bus running east and an 80' bus running west.
RR_Mel RichI can’t find the size of your bus wires in this post but #14 AWG wire has .12 volts loss at 40’ or 12.19 Meters at 2 amps for one wire or .24 volts for a pair.#14 AWG wire has .22 volts drop at 70’ or 21.336 Meters at 2 amps for one wire or .44 for a pair.
RichI can’t find the size of your bus wires in this post but #14 AWG wire has .12 volts loss at 40’ or 12.19 Meters at 2 amps for one wire or .24 volts for a pair.#14 AWG wire has .22 volts drop at 70’ or 21.336 Meters at 2 amps for one wire or .44 for a pair.
ATLANTIC CENTRAL What size wire is the buss? How often are the drops to the buss? What size wire are the drops? How long is the average drop? Are rail joints soldered? If the answer to the last question is no, or partly, I would change it to yes or mostly. Sounds like the mainline is one booster and secondary track another booster? I think I would have been inclined to the divide the layout geographicly (east side/west side) rather than by main/secondary trackage and keep wire runs shorter. Sheldon
What size wire is the buss?
How often are the drops to the buss?
What size wire are the drops?
How long is the average drop?
Are rail joints soldered?
If the answer to the last question is no, or partly, I would change it to yes or mostly.
Sounds like the mainline is one booster and secondary track another booster?
Sheldon
What size wire is the buss? 14 gauge solid.
How often are the drops to the buss? Every piece of flextrax has a pair of drops.
What size wire are the drops? 22 gauge solid.
How long is the average drop? 12 to 18 inches.
Are rail joints soldered? Only on the curves.
Sounds like the mainline is one booster and secondary track another booster? Correct.
RichI can’t find the size of your bus wires in this post but #14 AWG wire has .12 volts loss at 40’ or 12.19 Meters at 2 amps for one wire or .24 volts for a pair.#14 AWG wire has .22 volts drop at 70’ or 21.336 Meters at 2 amps for one wire or .44 for a pair. Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.