Large Scale Central

New RCS RailLinx PNP Booster

General Discussion
#49

I’d also like to know. While I’m not yet ready to begin investing in RC equipment (no point making engines go if there is no rails for them to roll on) this item has interested me as well.

Bob, if you feel the need to close the thread, could you open another one somewhere… perhaps the electronics forum for those of us with a real interest in the product.

Also, a thought for consideration. While I understand its your board, would it be possible for the advertisers to add a tag to the title of a thread like this. That way those who do want to read adverts don’t have to, and those who want to will know that it is a new item? Its just a thought… worth about… 1/10th of a cent I guess in this market.

#50
Greg Elmassian said:
I'm genuinely interested in the product, so maybe people who aren't really interested can hang off for a bit so I can get a few answers, please?

Rick, I was not able to get any more data from your site, so I apologize to everyone else.

What will be the cost?

You can email me the info if you don’t want to post more here.

Thanks, Greg


If I read it right on the original post $69. I would actually like to see more about it myself Greg…

#51

Hello everyone,

Sorry for the late reply’s, doctor appointments and physical therapy all day.

Greg, let’s see if I can answer your questions, $69.00 for retail price. Under the heat sink we have six Fairchild Semiconductors (and some other items, I really can’t say) rated at 14 amps each that are tide into each PNP pin-outs. This first version of the RailLinx Booster works with Aristocraft & RCS, we’re currently designing a version for QSI that should be available by the 2011 NGRC. Thanks for your suggestions with the “pin outs” with higher amps motors, with this first design I was more concentrated on PNP because that the way we’re desiging all the products lines of the New RailLinx System. (6amp PNP, Sound Card PNP, Live Steam PNP…).

Please be patient with our websites we are currently in the process of redesigning all four, but you will find the most up-to-date information at www.cordlessrenovations.com.

Tony, we have been testing this booster since June of last year and in every load bearing test our engineers and I put this board through, we haven’t had any problems with pin melting or over heating. And yes, that’s correct, we designed the Booster to dissipate “heat” from your decoder/throttle up to 12amps. I do not recommend drawing more the 12 amps for long periods of time, and soon we will add an inline amp meter to our product line to help your test the draw.

Rick Isard
Cordless Renovations, LLC

#52

Thank you Rick for the response.

However, with respect, my original question was:
“I would be interested to read how long the TWO output pins that will be carrying the 12 amp load, are going to last before they melt?”

Please define what “for long periods of time” means in Minutes? Hours? Days?

Did you test the pins to destruction at 12 amps, and if so how long did they last?

#53

Achhh, Tony, don’t be so fussy. He said “long periods of time.” What could be clearer? :stuck_out_tongue:

#54

Well, the
“input” to the decoder (from the socket) has the power pins doubled up, so you have 2 pins. Depending on whose specs you believe, each pin is good for either 3 or 5 amps, so that translates into 6 or 10 amps continuous. Here, 12 amps for short periods of time is totally believable, if not almost continuous.

On the output, there are only single pins to the motor, but feeding through the socket normally powers just one loco.

We will have to see Rick’s solution to connect 2 locos when one is “fed” from the plug and play socket.

If you were concerned, you could tap the motor output for the second loco off the board itself.

I don’t think I know of any locos that have the Aristo socket that can draw much over 3 amps continuous.

Just some misc. ramblings…

Greg

#55

Thanks Greg.

Most AristoCraft locos have a 3 amp Polyswitch on the PnP socket inputs.
There would have to be a separate input to the board so it would receive more than 3 amps. Certainly to achieve 12 amps throughput.
Just like as you say, it would need separate heavy duty output terminals to deliver 12 amps continuously.
I don’t think such output/input terminals would fit on the ends of the pcb. The ends are pretty well filled with what look like 4 x 3 amp diodes in a Bridge Rectifier configuration.
I guess we will all just have to wait and see.

#56
Steve Featherkile said:
Achhh, Tony, don't be so fussy. He said "long periods of time." What could be clearer? :P
I would expect mud maybe?? :P
#57

I have another curious question; Is this photo simply for size illustration? Or is that how it is intended to be mounted?

(http://freightsheds.largescalecentral.com/users/izzy0855/_forumfiles/Revolution.jpg)

The reason I ask is, if you stack it that way then stick it in an enclosed space, won’t the booster then tend to heat soak the decoder and possibly cause trouble – just like headers routed too close to a starter in a car? I’m not an expert on electronics that’s why I ask, it just looks a bit counter-intuitive that way if the point is to prevent cooking the decoder.

#58

Yes, the booster will be generating the heat, but it would be nothing compared to the heat the Revo would be generating on it’s own if it was carrying the load. Basically it will be better to have the booster dissipate 40 watts than the Revo.

The starter in a car was never intended to make heat, nor work in heat, so the analogy is not really applicable.

The heat in the air from the booster is nothing compared to the junction temperature of the output transistors.

So, the heat from the heat sink on the booster will have no effect in a measurable sense on the Revo.

Regards, Greg

#59
Greg Elmassian said:
The starter in a car was never intended to make heat, nor work in heat, so the analogy is not really applicable.
?
#60

Greg,
I think Allen was using the starter motor analogy in the sense that headers from an exhaust system that are run too close to the starter motor, may affect the performance of the starter motor because it can get too hot from the headers.

#61

Read the last part of Mik’s post above mine, after the picture.

Greg

#62
TonyWalsham said:
Greg, I think Allen was using the starter motor analogy in the sense that headers from an exhaust system that are run too close to the starter motor, may affect the performance of the starter motor because it can get too hot from the headers.
That's what I meant. I think. Intuitively it looks like the extra heat - especially if it is enclosed in say a smallish tender or road switcher carbody - might eventually adversely effect the performance or shorten the life of the decoder, no, not as fast as simply overloading it would. But shorter than if both were house separately or with fans. A different analogy might be to say if you run your 40 watts through the decoder you're throwing it in the fire, if you stick the other thing under it in a tight space means you put it in a pan on a burner - neither would seem to keep it cool.

I was thinking along the lines of how long most computers continue to work (or work well) after the fan fails… if you say that’s apples to oranges, then OK

#63

It’s not extra heat, it’s “instead of” heat… the Revo board will run cool as a cucumber since the booster will do all the work.

Also, again, the heat radiated from the booster board is nowhere near the temperature of the junctions of the transistors, so it will not affect the Revo.

The 40 watts is through the booster, the Revo will draw virtually nothing at all, again the booster will do all the work.

It’s not about being warm or cool, unless I misunderstand your question, which was (to paraphrase) “won’t it be bad for the heat from the booster heating up the Revo?”… the answer, as I have explained several times is no. You have to remember the air is cooler than the heat sink which is WAY cooler than the transistors.

So heating the revo to even the temperature of the heat sink on the booster (which is impossible) is no big deal.

Greg

#64

thanks greg, that’s why I ask, it’s how you learn :stuck_out_tongue:

#65

Yep, the cooling of semiconductors and the various temps involved is almost a science. I worked in consumer electronics where passive cooling was a paramount goal, to eliminate cost of fans and to avoid fan noise.

Regards, Greg

#66

Greg, I’ll take your word for what you say, but it still seems counter-intuitive. that heat-sink is sitting directly under the decoder… heat rises, there-fore it would be like placing the decoder over a stove burner… its gonna get cooked.

You talk about the junction of the transistors, but thats not a good comparison either… the booster is going to be handling up to 12amps… so that means it needs to dissipate that heat, which would be far greater than the decoder was designed to take.

I’m not trying to say you are wrong, just trying to explain why is seems counter-intuitive. Is there any chance you could show some math to show that the heat sink isn’t going to radiate enough heat over time to cook the decoder? At least if there was a fan blowing air through the heatsink, I would think the air directly under the decoder wouldn’t get as hot.

Please pardon my confusion

#67

The carrying capacity of the board(s) is 12 amps, but relatively little of that current is dissipated as heat by the on-board components.

Most of the (up to) 12 amps (actually the wattage resulting from the equation P=I x E) is dissipated as work and heat energy at the motor.

Think of a switch (the controller board(s)) controlling a 100 watt light bulb (the motor). The light bulb is dissipating most of the energy as light and heat. Very little energy is dissipated as heat by the switch. Not a perfect analogy for solid state circuits, but close enough to support an understanding.

Happy RRing,

Jerry

#68

Watts is Watts. It does not matter what is dissipating the watts as heat, it’s the same amount of heat. So if you do 24 watts on the Revo, it will most likely make the same heat as 24 watts on the booster, since they are both using FETs.

As an aside, not a lot of heat comparatively, that is why they use PWM. The FETs don’t make much heat because they are basically off, or full on, in the low resistance state. Cannot be compared to a linear amplifier.

But back to the question, suppose they are running twice as much heat from the booster… it’s the air temperature and whatever radiant heat (which would be small) more convection from the heat sink heating the air. The air temp, given the much larger heat sink, would not be as high as the air temp off the Revo. Remember that the Revo is not running any load to speak of now, so the heat does not matter.

I could explain in more detail, but just take this to keep it simple.

Greg