Here is one of those Hot Button Issues. I promise!
Here on BarstowRick.com I attempt to keep things simple so that a newbie can understand it. Remembering what I did and did not understand as a newbie myself. Electronics is way over my head and I don’t pretend to know the labyrinths of such. I’ll leave that to the electronics engineers. In the meantime we can all sort it out together.
Pulse Power – Reflections on the past:
Up until Pulse Power was introduced, you couldn’t get a realistic start-up with any of our toy train locomotives and diesels. You’d turn the throttle up until it took off and then crank it back down and hope nobody saw that. What we wanted and clamored for was realistic starts and stops. Keeping in mind we are talking about the 50’s and large motors that required and high amperage to turn them over. Notably, three amp’s or better.
Seems to me the first commercially made pulse powered transformers showed up in the 50’s gaining popularity through the 60’s. During this time there was talk of a transistorized throttle. Several model railroad wig wags (magazines) carried articles on how to build your own. I think it was in the late 60’s or early 70’s we finally got a commercially built transistorized throttles. What a difference it made. It should of outdated and killed pulse power on the spot. However, the numbers among-st hobbyist had developed into a measurable following. A fair majority of model railroaders liked the way their older locomotives and diesels operated on Pulse Power. Because of their demand, it’s still in use and with us to this day. So, one could conclude this is a good thing. Well, I’m inclined to think….maybe not.
I owned one of the first Pulse Power Transformers produced and it was a very bad performer. Trains would stutter, falter and hiccup as they started out. As units improved, some of the performance issues cleared up. But all to often you’d find yourself going right back to square one, with stuttering locomotives. The late 60’s saw numerous improvements in our motive power. Motors that didn’t need the high amperage but didn’t perform well with the Pulse Power Transformers. Needless to say I wasn’t happy with that kind of performance.
Pulse Power: What is Pulse Power? The simple answer it is early electronics that used AC spikes, AC added to DC. to overcome the inertia of the locomotive. To break the inertia of an electric motor and cause it to run with a realistic crawl, from a dead stop up to full speed. Usually associated with wire wound rheostat’s. The first units out were called a lot of things, in a less then a complimentary way.
Here, I will use “AC Spikes,” to denote an unrefined spike of voltage. Although this is technically incorrect it best describes the action taking place. Gosh many of us used AC spikes, to describe pulse power for years.
Transistorized Throttle: What is it? It’s a throttle that tout’s using the purest form of filtered DC and injects a modified form of AC, to control a train locomotive or diesel from a dead stop, up to full speed and back to a stop. Now did that sound like a contradiction? It is! Sort of. Just don’t ask an electronics’s engineer for the complicated explanation. We’ll be here all day.
The manufacturers use a potentiometer to control the amount of current that goes out to the train. There is a type of memory computer chip that controls the automated increase and decrease in the preferred speed of your train, often referred to as Momentum. If you are lucky enough you can get one with a Brake feature that performs as does the ones, on the 1:1 foot scale.
What’s the difference between a Pulse Power and Transistorized throttles? The answer I’ve been taught and may be over simplistic is: One uses AC spikes to overcome the inertia and the other uses injected DC to do the same. If you haven’t already noted, you are about to learn that may or may not be true.
Keep in mind. when pulse first came out it was called pulse because of the AC Spikes =Jabs of AC=Injected AC, all in an attempt to describe Pulse Power. Today’s refined pulses are called PWM = Pulse Wave Modulation.
Now what about DC? What I’ve learned from Mr. Mmagliaro and others on TrainBoard.com is they now have a rectified DC Pulse. More on this in Pulse, PWM & DCC posted here on BarstowRick.com.
Now to keep the confusion out of the ranks, which failed miserably in the past. Pulse Power and it’s copyright only refers to a very harsh pulse, or as it was described to many of us as AC Spikes, Injected AC and ‘Jabs’ of higher voltage. It cannot refer to a Transistorized Throttle aka Momentum with a memory chip to control the speed and stops, as that’s a different copyright. Begging a lot of unanswered questions.
I’ve invited friends who know electronics to chime in and so far I have Mr. Mmagliaro and Greg M’s permission to use their thoughts on the subject. On TrainBoard we got into a discussion and believe me when I say there are some hard core loyalist to Pulse Power. It’s true. Defensive and can be aptly described as “Guardians of the Pulse Power”.
Today, those who prefer a transistorized throttle over the pulse power, consider the pulse technology, to be dirty technology. Why? Because of the type of AC pulse or spikes. It will cause your locomotives to run warmer and if UN-monitored to run hot! Should you forget to shut it off, you can burn out an electric motor. How do I know? I did! To long of a Rick’s Story Time, for now.
The newer Pulse Power Packs, have been modified and refined their performance is by far better then the one I had.
One of the local BVMR’s has one of the newer ones. He doesn’t use it anymore as he graduated from Analog DC to DCC. A happy conversion I might add. He still has the option to use his pulse power throttle. It’s still hooked up to a DPDT electrical switch on his layout. One fliip of the DPDT, and he’s back in business. He can then fire up and run some of his older HO diesels. The ones with the high amperage motors.
The Transistorized Throttle has it all over the Pulse Transformers. I’ve been extremely happy with my throttles and I would recommend them to any future toy train enthusiast or model railroader. The starts and stops are as realistic… as you are going to get.
The power packs or transformers I’d recommend are as follows: MRC ControlMaster 20 and MRC’s Tech lll Power Command, Model #9500. Both, produce the purest form of filtered DC. The Tech lll, comes with meters which I find helpful. My favorite of these three, saving the best for last: The Controller 35M, with adjustable momentum. I love being able to adjust the momentum and the operational results are right on! Dead ringer for the 1:1 foot scale.
Terminology: Now hear this. Well that’s what I started to write. Here’s the problem. Most of us as modelers don’t have the head knowledge, proof and evidence with regard to some of the claims we’ve read, heard and depended on from alleged educated hobbyist Many that we depended on and who operated our local hobby shops. Confounded claims all made over the years in our model railroad wig wags (magazines) and other periodicals.. A lot of it, is over our heads and anything but simple to understand. Which only makes it extremely difficult to discuss this openly.
Disclaimer: I better add a disclaimer. Today, as I write and you read this. We have some hobby shop owners that are educated and can lead you in the right direction. Things have changed since the days I first started visiting our one stop and shop… Gun Shop, Bicycle Shop, Fishing & Tackle, Sports Paraphernalia, Little League Uniforms, Boy Scout Gear and oh yes we have car models and some train stuff otherwise know as the Local Hobby Shop. Gosh those folks at Muenzers (local gun shop, bicycle shop and much, much more) were the greatest as they attempted to help me, educate me and provide me with the best model train stuff out there. They worked hard to serve me so I could enjoy my hobby. I think it’s safe to say they learned right along with me.
Do I dare say? One of the reasons we need as accurate a terminology and definitions base as is possible.
As always, I want you to read the resources I provide here and decide for yourself what you want to believe. You’ve read by now where I say: Take from here what you want and…..leave the rest behind.
Elaborating: How does this technology work? The simplified version:
I went to lunch with a friend of mine and talked to him about this very subject. I asked him about the oscilloscope and he said true DC would be a straight line. I asked him about the upward blips and he said that’s AC. Saying it’s dirty DC. I asked him about the difference between Pulse Power and a Transistorized Throttle. He then said pulse power uses AC to to get the motor to roll over and is usually associated with an older type of wire wound rheostat. Not so with the new ones but that’s how they got started. The newer Transistorized Throttle is a pot. aka potentiometer, that controls the power out to the electric motor and it too uses AC to nudge the electric motor. The only way to get purified DC is to use a car battery or battery of your choice or a very filtered rectifier. Credit to Greg M., a Ham Radio Operator, fellow Model Railroader and heavily into electronics. Confirming what Mr. Mmagliaro and what many of my friends on TrainBoard have said.
You will have a chance to look at a website where you can find what appears to be pictures of an oscilloscope and the various pulses put out by an assortment of transformers or power packs. What I see on that website is a DC sine wave with perhaps some signal distortion. The claim is you can see the AC pulse. It turns out that is true. DC is a straight line so any blimps that may be visible are AC.
The Oscilloscope, A shout out to Mr. Mmagliaro for bringing this to my attention. Thanks to Sumida Crossing for making this available. See: http://www.sumidacrossing.org/PhotoAlbums/ElectricalSystemsPhotos/DCTestingPhotos/
Incidentally you will find my old power pack, the MRC 501. It’s the first one illustrated. Looks like they dug it up out of my back yard. The top switch is the “Pulse” switch, barely legible. Click on the power pack and you will find a slide show with a picture of it’s guts and the then latest version of a wire wound rheostat and transformer.
Confusion: By now you’ve read where I say something about the confusion. It is confusing when Pulse Power and Transistorized Throttles “Both” use AC to overcome the inertia of the electric motor to get the train rolling. Makes them sound like they are one and the same. They aren’t.
My Original Power Pulse Transformer: What happened to mine? I gave it to a friend, who gave it to a friend and then because of it’s poor performance we buried it in our backyard. What do you expect from a Mortician’s Son. Happiest service we ever had. Good bye to an annoying and frustrating….friend? Uhh,,,err we buried the transformer not a friend. Although, judging from the response we got regarding the cowboy hat, belt buckle and boots we buried you’d of thought so. Grin! Spooked a number of kids who thought it was ok to take a short cut through our back yard from the alley way to the street. Put a temporary stop to things. Funniest thing to watch their expressions on their faces. Surprise, disbelief and denial was the first responses we saw most often. See what happened to the last kid that ran through here.
DCC does it use Momentum or Pulse? Now here’s a topic that just begs to follow on the heels of this one. With a follow up question: Does DCC use AC spikes to get the motor to roll over? Simple answer is yes,. Should you want to start up a heated debate that will out do the one regarding Pulse versus Momentum. Ask that question on any toy train or model railroad website. I won’t even touch that debate here on BarstowRick.com. I’ll let DCC Guy handle that discussion.
I hope that helps!
Ron McF., Added a comment here. It’s worth the read. If you don’t see it below this posting. Go back and click on comments under the heading and it should pop-up.