WHY?
Quote from: Atlantic Central on January 16, 2011, 09:36:33 PM
WHY?
I have noticed a number of threads have been deleted lately. After I post to a thread, I like to keep track of it to see others' opinions and in hopes that the thread's originator will let us know the final solution, if any, to his problem. I suspect you do the same.
I hope it is not censorship, and would certainly expect that any board monitor that deleted a thread would at least post that he/she had done so. It would be even better if the monitor told us why, even if he/she wanted to avoid mentioning who.
The other possibility is that the originator of the thread deleted it either because he/she got an answer or because he/she didn't get an answer. And occasionally the originator feels he/she has been slighted in some way and deletes his/her thread. That happened recently when an originator felt I had insulted him by not addressing a response to him personally. And sometimes a member leaves in a huff and deletes all his threads.
Not knowing why is more than a little bothersome.
Jim
Jim,
I believe you have come up with the most likely reasons why these things happen here and in other forums.
It is a little bit discerning when I have gone back to reread a post that I thought had some points of interest and found it gone.
Many times I copy an interesting conversation and save it into a Word document so I have the info.
The issue I am running into is cataloging the conversions so I can find them again.
I have a lot of info, links on the pulse width issue anyway as I have worked with PWM for many years in industrial drives.
Maybe Bachmann can start keeping all the conversations
Rich
Howdy. I am sorry I did not email it to myself. Good information there. Will make sure I do it in future.
Best Wishes,
Jack
Please excuse me I deleted it due to it was alittle over my head . I was just questioning the fact that 3 different G scale Loco Manuel's define 3 different types of dc power packs . Being the FA unit I'm getting on Thursday , I pulled up the Manuel on the aristocraft site for the FA-1 units and started reading and when I saw the note on using Pulse Width Power . I didn't want to jump the gun until I got the Locomotive sitting in my hands Due to it is an FA-2 unit and I wasn't sure if they were the same . My Aristo Craft center cab didn't have any type of power pack listed ,the USA GP unit just said 0-22 volt DC and when I read about the FA unit and needing P.W.C as I should have waited and asked when I got the unit and read the Manuel . And if I actually need to buy another power pack to operate this locomotive ...
A/C I did read all 8 pages of the thread you posted on your findings and learned alot from it . Also got schooled on it from one of the electricians at work .When I receive the FA unit Thursday I will post and let you know what it says .
Didn't mean to create a S.N.A.F.U
regards : Mark f
AC can you repost the link you gave !
thanks: Mark f
Dear Sheldon,
Ditto for me re the thread.
Or if you would be so kind, email to me: jsmvmd at aol period com
Best Wishes to all,
Jack
To all, sorry to be so long in getting back to this, it's been a busy week on other fronts.
Here is the link to my long runnig thread on Radio Control.
Unfortunately my book is still only moving forward slowly due to several family issues, BUT, there is light at the end of the tunnel as some of those issues are winding up and will be off my plate soon, in just a few weeks!
My new modular version of my layout is designed and it too should be able to move forward shortly.
http://www.bachmanntrains.com/home-usa/board/index.php/topic,2893.0.html (http://www.bachmanntrains.com/home-usa/board/index.php/topic,2893.0.html)
The OP e-mailed me and explained as he did on here as well. No problem, I was just wondering?
The other layout that my system is installed on is still working very well. We operated on it just last Tuesday. We do have just a few very minor improvements planned.
Thank you to all who are interested, while progess is slow, the book and system documentation are coming.
Sheldon
AC-
Well, if the book is coming can the movie be far behind"
-- D
Dear Sheldon, Thanks !
Dear Don, Droll !
Best Wishes, Jack
I did get my G scale F unit , it is straight D/C . I'm kinda disappointed in some ways . Not being Sound ready or DCC ready . The seller didn't give enough information . Beautiful Loco though. And yes it does recommend a Pulse Width Control . It has the smoke unit and fan for smoke ,lights and motor, 3 switches , but no means for sound or dcc , i'm going to keep it D/C . I've looked at so many sound boards and just want to use track power not battery power for the sound board . And install something not so complicated . So I am assuming I will have to hard wire a sound board and speaker , and reed switches in the unit . Any ideas on a sound board and can someone give me an illustration on how to wire the board in . I want to attempt this .
thanks regards mf5117
I did some reading and got a better understanding about pulse width control . I understand that with PWC your Locomotive at an Idle the motor will sit and rock back and forth , causing the motor to heat up if the motor is not equipted to handle PWC . like with the Aristo-Craft Locomotive's that allow PULSE WIDTH CONTROL . The USA Locomotives only say in the Manuel 0-22 V DC power . I bought an Aristo-Craft 10 amp PWC not knowing that it could damage my Bachmann and USA trains Locomotive's running on DC power . As it doesn't say anything about PWC in their Manuel's . So if you went and bought a locomotive at a Hobby Shop and all they had was the aristo controller's you could possibly burn up your Locomotive and not Know the reason . Am I correct ....What I'm saying is ,if I had my controller set to 0 speed waiting for the Battery to charge on my sound board on my Locomotive due to the battery on the board takes over at under 6 volts power and it is a new install . I have the potential to burn my locomotive up . This is nice to know and I'm glad I asked a few Questions before I actually started running my Loco's .As for now I'll stick with my old MRC 7000 and run my trains ....
EDIT : the stator inside the motor will pulse back and forth at idle .Causing the motor to heat up. And possibley burning the drive motors up...
mf5117,
If your loco is not moving, then there is no power going to the motor, so it can't "burn up" at idle. If you are refering to the fact that you can "start" the throttle and light the lights before the motor starts, how long would you logicly let it sit like that? And, since the pulses are very spread out at that point, not much heat will build up in the motor. Likely no more than pulling a heavy train at 3/4 throttle.
What type of control are you talking about - onboard radio with the Aristo Train Engineer? Using track power to charge onboard batteries?
In theory, some motors will run hotter at SLOW SPEEDS on pulse width control, but in the case of almost all G scale trains, the motors are big enough and have enough venting for this to not be a problem.
Pluse width modulation IS DC, it just uses pulses of full voltage rather than partial voltage to control speed.
Not sure where you are getting all this negative info on PWC, Many of us have used it for years, even with HO and N scale with no problems. I've never burned up a motor in any model train on any kind of throttle in over 40 years.
Sheldon
Decoder signal to the motor.
Zero throttle. Zero volts.
(http://i98.photobucket.com/albums/l267/richg1998/DCC/ZeroThrottle.jpg)
Forward, half throttle.
(http://i98.photobucket.com/albums/l267/richg1998/DCC/FWDHalfthrottle.jpg)
Reverse, minimum throttle.
(http://i98.photobucket.com/albums/l267/richg1998/DCC/REVMinimumthrottle.jpg)
DCC signal as applied to a DC motor when using stretched zero bit option. This causes the motor to rotate fwd and rev in very small amounts.
(http://i98.photobucket.com/albums/l267/richg1998/DCC/Stretchzerobitwaveform.jpg)
Rich
Download and study the photos. A picture is worth a least a thousand words.
A meter connected to the motor will read DC voltage when the motor is connected to a decoder. The 12 volt pulse gets wider for more speed. Even at speed step one on 128 mode, there is a 12 volt pulse but very narrow pulse width.
With a DC motor connected to the DCC signal/track voltage, you will see AC volts because of equal positive and negative signal transitions. As the positive or negative zero bit gets wider, you will start to see DC voltage on the motor but it will buzz because of the AC.
Some motors will buzz with older lower frequency decoders. Newer decoders now operate at a higher frequency. I have the frequency number somewhere.
My older SoundTraxx LC decoders could cause buzzing in some locos but the Tsunami do not, at least in my locos.
Rich
If the following discussion is too technical and boring, please skip on down to the last paragraph.
Pulse Width Control, even though unipolar, is still a mixture of dc and ac. The lower the throttle setting, the higher the frequencies of the ac component. The higher the frequency, the better the motor inductance rejects it. So the current flowing through the motor at low throttle settings is mostly dc. As you advance the throttle, the ac component contains more lower frequencies. At some point, these will try to rotate the motor's armature (not its stator.) But unlike DCC, the current will rotate it in one direction only. Cogging action, the magnetic attraction between the armature sections and the motor's field magnets, will pull the armature back again. Past some critical throttle setting, the pulses will be wide enough to advance the armature in spite of the cogging action and the motor will begin to run. Just below this point is the maximum current that can be run through the motor without it running. If you compare this with the amount of pure, filtered dc that may be put through the same motor just before it starts to run, you will find that the motor consumes more power with the pure dc than it does with the PWC ac + dc. And since in neither case is the motor dissipating heat by turning, it will heat up more with pure dc if left barely not running.
There is one exception. That concerns coreless motors which have no iron in their armatures. With no iron, the inductance of the armature is much lower. With lower inductance, the motor is less able to reject the ac component of the PWC. So the total ac + dc current that PWC can push through a coreless armature is higher. Add in the reduced cooling of the armature windings when there is no iron to conduct the heat away and you find that coreless motors are not good candidates for running on PWC. The only model locomotive with a coreless motor that I am aware of was one that LGB put out. It started smoothly on dc because coreless motor have no cogging action but there were reports of it being damaged by PWC and by DCC.
Bottom line, we use PWC to start the motor turning at lower speeds than is possible with straight dc. So if we apply straight dc, we can apply more of it before the motor starts than we can by applying pulses. More power = more heat in the stopped motor.
Jim
I'M going to read these post a few more times and get it clear in my head . As I have a few more questions I need to ask . Sorry Jim I meant to say armature .
I'm running G scale DC locomotives , with no TE
thanks again Jim ,Rich , Hunt and AC
Regards: mark fuller MF5117 RR
That's what I was told Hunt but the way it was explained to me was that . OK I have 3 USA Locomotives . The Aristo-Craft Locomotives I have say use PWC ,they are DC Locomotives though, not DCC ready . I took The USA Trains Locomotive One of them to get sound installed in it . I had already bought the ARC 10 amp controller ,due to I had caboose's with lights and smoke one of the ArC Locomotives had sound and smoke, lights already . the Manuel said recommended PWC controller . So I bought the higher amped controller for the power to run smoke ,lights another engine etc. " consist" . My Bachmann Loco I run in the house .
The tech at the Hobby shop said I shouldn't use PWC on the USA or Bachmann Locomotive .As It wasn't good for the sound boards of the Locomotives . If they sit at an Idle the armature would sit and "as Jim said " cog back and forth . And eventually burn up the motors and even the boards . So I was thinking well hmmm guess I'll run one manufacturer's train with their controller and the other with theirs . So that's kinda where I'm at .