Electrical

[Anonymous]

QUOTE: Originally posted by timmatthews


It's not that I have anything against buying MRC, but that I have enough electronic junk laying around and can design/construct something for less cost.

Half of the fun for me is the electrical aspect of Model RR. I have already built and tested a straight DC throttle which consists of an Operational Amplifier circuit set up as a voltage regulator driving an NPN Darlington power device.

Pulsed gives more torque for better low speed performance, but can make the motor run hotter. MRC uses unfiltered full wave rectified sine shaped pulses, some models produce 60 Hz at low speed settings with lower voltage alternate pulses again at 60 Hz for a total of 120 Hz. As the speed is increased both sets of atlernating pulses increase in amplitude until they are at equal level at 120 Hz at full throttle. Works very well.

If operating off batteries you don't have the sine shaped option or 60 Hz frequency reference. 30 to 100 Hz works, the best frequency is the lowest at which your locomotive crawls without vibrating, but if the headlight is a LED you want at least 50 Hz to reduce annoying headlight flicker. The motor growls more realistically at low frequency (diesels only; growling steam locos are very unrealistic!). Square shaped pulses are easiest to generate but result in the highest motor heating and loudest noise. Triangular shaped (ramped) pulses are also fairly easy to generate with opamps and are a reasonable approximation to a sine shape to reduce heating and motor noise, but the drive transistor will then require a heat sink to prevent it from overheating with anything other than square pulses.

A good system is one which superimposes filtered DC at low voltage with short duration full voltage sine or triangular spikes, the DC voltage rises and the spikes can increase in duration as the speed is advanced. This combines torque with cooler motor operation. There's a lot of room for experimentation in this area, have fun.

An important point - make sure you have a current limiting safety device in series with the power pack and track. This can be a PTC (positive temperature coefficient) device that limits current as it heats. They are available specially made for this purpose in a variety of trip currents; the automotive light bulb in common use is an example of a device made to work as a PTC through the ingenuity of RR modellers. Or use a current sense resistor in series with the track and a circuit to shut down the power if it detects an overcurrent of say 2 amps so you can MU locos.

[Anonymous]

QUOTE: Originally posted by timmatthews


It's not that I have anything against buying MRC, but that I have enough electronic junk laying around and can design/construct something for less cost.

Half of the fun for me is the electrical aspect of Model RR. I have already built and tested a straight DC throttle which consists of an Operational Amplifier circuit set up as a voltage regulator driving an NPN Darlington power device.

Pulsed gives more torque for better low speed performance, but can make the motor run hotter. MRC uses unfiltered full wave rectified sine shaped pulses, some models produce 60 Hz at low speed settings with lower voltage alternate pulses again at 60 Hz for a total of 120 Hz. As the speed is increased both sets of atlernating pulses increase in amplitude until they are at equal level at 120 Hz at full throttle. Works very well.

If operating off batteries you don't have the sine shaped option or 60 Hz frequency reference. 30 to 100 Hz works, the best frequency is the lowest at which your locomotive crawls without vibrating, but if the headlight is a LED you want at least 50 Hz to reduce annoying headlight flicker. The motor growls more realistically at low frequency (diesels only; growling steam locos are very unrealistic!). Square shaped pulses are easiest to generate but result in the highest motor heating and loudest noise. Triangular shaped (ramped) pulses are also fairly easy to generate with opamps and are a reasonable approximation to a sine shape to reduce heating and motor noise, but the drive transistor will then require a heat sink to prevent it from overheating with anything other than square pulses.

A good system is one which superimposes filtered DC at low voltage with short duration full voltage sine or triangular spikes, the DC voltage rises and the spikes can increase in duration as the speed is advanced. This combines torque with cooler motor operation. There's a lot of room for experimentation in this area, have fun.

An important point - make sure you have a current limiting safety device in series with the power pack and track. This can be a PTC (positive temperature coefficient) device that limits current as it heats. They are available specially made for this purpose in a variety of trip currents; the automotive light bulb in common use is an example of a device made to work as a PTC through the ingenuity of RR modellers. Or use a current sense resistor in series with the track and a circuit to shut down the power if it detects an overcurrent of say 2 amps so you can MU locos.

[Javern]

QUOTE: Originally posted by flee307

Q; Have you had any success contacting a builder, such as Life Like, and getting intelligent answers to technical questions?

A: Who knows, I don't speak Chineese...........

LOL this is one of the funniest posts I've seen

[Javern]

QUOTE: Originally posted by flee307

Q; Have you had any success contacting a builder, such as Life Like, and getting intelligent answers to technical questions?

A: Who knows, I don't speak Chineese...........

LOL this is one of the funniest posts I've seen

[cacole]

Mainline Modeler magazine February 1995 issue had complete schematics for a DC throttle system called the Cooler Crawler that is very good. We use the Cooler Crawler system to operate the Cochise & Western Model Railroad Club's 20x40 foot HO-scale layout, with 8 walk-around controllers available. You can find the Cooler Crawler article on-line at http://www.tractronics.com under the Mainline Modeler articles heading.

[cacole]

Mainline Modeler magazine February 1995 issue had complete schematics for a DC throttle system called the Cooler Crawler that is very good. We use the Cooler Crawler system to operate the Cochise & Western Model Railroad Club's 20x40 foot HO-scale layout, with 8 walk-around controllers available. You can find the Cooler Crawler article on-line at http://www.tractronics.com under the Mainline Modeler articles heading.

[Anonymous]

A good friend of mine built 7 of his owns throttles, but is using an old Lionel, one of those double handled jobbies, power pack with his home built throttles. They are plug in around his layout.

[Anonymous]

A good friend of mine built 7 of his owns throttles, but is using an old Lionel, one of those double handled jobbies, power pack with his home built throttles. They are plug in around his layout.

[Anonymous]

Tim--

The Pete Thorn books are good but out of print. You can find them used, though, or check your library. I built some projects from Easy Electronics Projects for Model Railroaders that worked pretty well.

You might also check the internet with a search on Google or Yahoo--there are many, many clever peple who are model railroaders. Here are some sites I've looked at: http://www.awrr.com/awrrhome.html, http://home.cogeco.ca/~rpaisley4/CircuitIndex.html, and http://users.rcn.com/weyand/tractronics/articles/articles.htm

Gary

[Anonymous]

Tim--

The Pete Thorn books are good but out of print. You can find them used, though, or check your library. I built some projects from Easy Electronics Projects for Model Railroaders that worked pretty well.

You might also check the internet with a search on Google or Yahoo--there are many, many clever peple who are model railroaders. Here are some sites I've looked at: http://www.awrr.com/awrrhome.html, http://home.cogeco.ca/~rpaisley4/CircuitIndex.html, and http://users.rcn.com/weyand/tractronics/articles/articles.htm

Gary

[preceng]

I am building a control panel with LED indicator lights. What is the best way to supply power for them? What voltage should I use?

[preceng]

I am building a control panel with LED indicator lights. What is the best way to supply power for them? What voltage should I use?

[timmatthews]

Ed,
Yes, I intend to do signals as well. They will work in conjunction with automatic block control. This will be accomplished with all discrete logic, probably TTL or CMOS, and relays. The big cost for me will be the signal towers themselves and of course time. The electronics are cheap and the 24 volt relays are free.
Tim

[timmatthews]

Ed,
Yes, I intend to do signals as well. They will work in conjunction with automatic block control. This will be accomplished with all discrete logic, probably TTL or CMOS, and relays. The big cost for me will be the signal towers themselves and of course time. The electronics are cheap and the 24 volt relays are free.
Tim

[Anonymous]

Tim,

If you enjoy the electronic end of the hobby, I figure you will get into signals someday. I hope to have an operating signal system on my layout someday. All my queries into this have generated one common theme . . . to have functioning sygnals, you gotta get out the checkbook. Let me know if you come up with some low cost ideas for signals. BTW, my electronics background consists of taking one basic circuits class in college and watching my dad build a computer back in the old days. Good Luck. - Ed

[Anonymous]

Tim,

If you enjoy the electronic end of the hobby, I figure you will get into signals someday. I hope to have an operating signal system on my layout someday. All my queries into this have generated one common theme . . . to have functioning sygnals, you gotta get out the checkbook. Let me know if you come up with some low cost ideas for signals. BTW, my electronics background consists of taking one basic circuits class in college and watching my dad build a computer back in the old days. Good Luck. - Ed

[der5997]

Peter J. Thorne,s "Electronic Projects for Model Railroaders" (5th printing in 1979, but probably updated since.)
P.J.Thorne "34 New Electronic Projects for Model Railroaders (1982 - and also doubtless updated since )
Both of these are Klambach publications. You should be able to get them from your Local Hobby Store [LHS in these forums]
These have all the circuits you will need. Also, it sounds as if you can freelance on Peter's basic designs. I wish I could. I've had great success with his more simple circuits, but I could never trouble shoot the SRC (oops! SCR, maybe I'm electronically dyslexic as well!) throttle, and to this day it is lifeless in the attic. [:(]

[der5997]

Peter J. Thorne,s "Electronic Projects for Model Railroaders" (5th printing in 1979, but probably updated since.)
P.J.Thorne "34 New Electronic Projects for Model Railroaders (1982 - and also doubtless updated since )
Both of these are Klambach publications. You should be able to get them from your Local Hobby Store [LHS in these forums]
These have all the circuits you will need. Also, it sounds as if you can freelance on Peter's basic designs. I wish I could. I've had great success with his more simple circuits, but I could never trouble shoot the SRC (oops! SCR, maybe I'm electronically dyslexic as well!) throttle, and to this day it is lifeless in the attic. [:(]

[Anonymous]

Kieth Gutereze (sp???) used to do the electronics symposium in MRR. If you have the ability, find back issues on building throttles. They were from the late 80's and early 90's I believe.

[Anonymous]

Kieth Gutereze (sp???) used to do the electronics symposium in MRR. If you have the ability, find back issues on building throttles. They were from the late 80's and early 90's I believe.

[Anonymous]

I also once built a boxcar with nickel metal AAA battery pack that charged through a full wave from the track and supplied power to a loco through wires and a MOSFET power cord from an electric RC plane throttle radio control. Worked great on dirty nasty track from up to 1/4 mile away. Downside, couldn't keep batteries up over 20 min. even suppling power through clean track. Guy who loaned RC stuff wanted it back and told me what they cost new. Made DCC seem cheap!

[Anonymous]

I also once built a boxcar with nickel metal AAA battery pack that charged through a full wave from the track and supplied power to a loco through wires and a MOSFET power cord from an electric RC plane throttle radio control. Worked great on dirty nasty track from up to 1/4 mile away. Downside, couldn't keep batteries up over 20 min. even suppling power through clean track. Guy who loaned RC stuff wanted it back and told me what they cost new. Made DCC seem cheap!

[Anonymous]

Q; Have you had any success contacting a builder, such as Life Like, and getting intelligent answers to technical questions?

A: Who knows, I don't speak Chineese. Most don't have the resources as most model companies are small time due to sales volume and don't want to spend $ answering questions. That's where this forum comes in. Ask away!

[Anonymous]

Q; Have you had any success contacting a builder, such as Life Like, and getting intelligent answers to technical questions?

A: Who knows, I don't speak Chineese. Most don't have the resources as most model companies are small time due to sales volume and don't want to spend $ answering questions. That's where this forum comes in. Ask away!

[Anonymous]

Yes MRC make pulse units. I built one long time ago from article in MR. It Worked for two weeks. I then didn't have knowhow to fix it. I also have used an old AT computer power supply, $2, and an adjustable voltage regulator IC from Radio Shack (with the other parts needed to work $5) to build one. Works great but is limited to 12 volts max and needs a 12 volt car light bulb to load it enough to start the power supply. I then bit the bullet and purchased an MRC Prodegy DCC for Xmas and haven't looked back since. It's so nice!

[Anonymous]

Yes MRC make pulse units. I built one long time ago from article in MR. It Worked for two weeks. I then didn't have knowhow to fix it. I also have used an old AT computer power supply, $2, and an adjustable voltage regulator IC from Radio Shack (with the other parts needed to work $5) to build one. Works great but is limited to 12 volts max and needs a 12 volt car light bulb to load it enough to start the power supply. I then bit the bullet and purchased an MRC Prodegy DCC for Xmas and haven't looked back since. It's so nice!

[timmatthews]

Thanks for the reply Ed.

It's not that I have anything against buying MRC, but that I have enough electronic junk laying around and can design/construct something for less cost.

Half of the fun for me is the electrical aspect of Model RR. I have already built and tested a straight DC throttle which consists of an Operational Amplifier circuit set up as a voltage regulator driving an NPN Darlington power device.

As for the walk - around, I have a small 2" x 3" plastic box, with a pot and toggle switch, attached to the main power supply through a 25 foot cord.

Just investigating options. I'll probably have to do some experimentation.

Tim

[timmatthews]

Thanks for the reply Ed.

It's not that I have anything against buying MRC, but that I have enough electronic junk laying around and can design/construct something for less cost.

Half of the fun for me is the electrical aspect of Model RR. I have already built and tested a straight DC throttle which consists of an Operational Amplifier circuit set up as a voltage regulator driving an NPN Darlington power device.

As for the walk - around, I have a small 2" x 3" plastic box, with a pot and toggle switch, attached to the main power supply through a 25 foot cord.

Just investigating options. I'll probably have to do some experimentation.

Tim

[Anonymous]

Tim,

It sounds to me you don't want to buy a MRC power pack. I don't understand this because I have been very happy with mine. I wish you luck. If you do find a successful formula for this, and can come up with a walk-around option, I would like very much to hear what you learned.

Ed