Hello,
I have a question regarding LED lights.For starters I installed some white LED lights in my gp 30 with the proper resistor to make them directional after hard wiring the locomotive since it was a older split frame.They work well directional ,but the light that goes out on the back side of the engine will flicker.I did some research and found that I am missing a capacitor in the circuit to absorb the spikes generated by the motor and in time will blow the LED lights.Someone said to put a capacitor across the motor leads to absorb the spikes .Can anyone recommend the right type to use polarized ,non polarized ,???Thanks.
Johnny Adam
Depending on how much of a "flicker" could be caused by dirty wheels. How are they? If they are dirty and you need a method to clean them, just let me know.
Hello,
The wheels are clean and it runs like a Swiss watch.The pickups were all tuned ,adjusted and everything was wired and soldered in.The flickering is on the reverse light only either direction.So if it is going in reverse the forward light flickers when it should be out.And when going in reverse the forward light flickers a bit and should be out.Thanks
Johnny Adam
are you using this engine wired for a DCC module, or are you using this engine without having installed a DCC module?
Rich C.
Quote from: brokenrail on October 22, 2015, 12:07:09 PM
Hello,
I have a question regarding LED lights.For starters I installed some white LED lights in my gp 30 with the proper resistor to make them directional after hard wiring the locomotive since it was a older split frame.They work well directional ,but the light that goes out on the back side of the engine will flicker.I did some research and found that I am missing a capacitor in the circuit to absorb the spikes generated by the motor and in time will blow the LED lights.Someone said to put a capacitor across the motor leads to absorb the spikes .Can anyone recommend the right type to use polarized ,non polarized ,???Thanks.
Johnny Adam
Show us the circuit you are using. Right now I am assuming this is strictly a DC loco operation with DC power pack.
I do remember the constant lighting using 1.5 volt bu;lbs many years ago but have not seen a circuit to do this with LED's which as you know have a little higher voltage requirement.
Rich
if this is dcc keep in mind that capacitors stop dc and pass ac. the dcc waveform is a form of ac. bettter to use the function leads of the decoder for your lighting, as intended by the manufacturer of the decoder.
if this is a dc locomotive, use a non polarized capacitor. remember that, while you are only using one polarity to run your locomotive, you reverse that polarity every time you change direction.
It is a simple circuit of two - 3 mm Led lights .One for the front and 1 for the rear and ONE 800ohm 1/4 watt resistor that is all you need to make it work .The
led's take 3 volts to light.They reverse direction perfectly ,nice and bright.I am using DC . I have seen in automotive applications on the air compressor magnetic
coil they use a capacitor to protect the sensative low voltage electronics from the voltage spike created when the coil is turned off and on ,but they do not reverse polarity in this 12 volt dc circuit like we do with our model trains in dc.I have noticed that Bachmann uses some type of capacitor on there new motors ,but looks can be deceiving
Johnny Adam.
Ok that sounds good. Does make sense. Reverse the polarity and the LED's switch on and off.
The only locos with caps on the motors I have seen are some the DCC ones.
Rich
Quote from: brokenrail on October 22, 2015, 01:13:07 PM
The flickering is on the reverse light only either direction.So if it is going in reverse the forward light flickers when it should be out.And when going in reverse the forward light flickers a bit and should be out.
Ok
JA, this is a little different than what you first stated....
Quote from: brokenrail on October 22, 2015, 12:07:09 PM
They work well directional ,but the light that goes out on the back side of the engine will flicker.
I have done the same as you just not with a split frame and run DC as you, and the only occasions I get an LED flickering in the opposite end than the direction of travel is when the wheels are dirty. And it is also veerrrrrry brief and hardly noticeable if you were not looking directly at it. It was, I believe
Mr. Banner, who explained why this happens, some time ago in a post here.
So based on your response, that leaves checking your soldered connections, I believe. No need for any CAPS; using the LED and proper resistors hooked up the correct legs of the Light Emitting Diode for the directions you want them to light in should work fine. Any other electrical junk in between those 2 things?
...or, if not in between the LED and resistor, is anything in line with them?
Here's a circuit for a basic directional light set up using LEDs. The capacitor is nonpolarized to deal with the polarity reversals when changing direction.
(http://www.personainternet.com/bkingsmill/train%20stuff/SCH%202%20LED%20LOCOMOTIVE.jpg)
Len
I've wondered if this question would ever come up again. I posted about it in the past. I have also read the explanation about motor spikes and dirty track/wheels causing the reverse light flicker. I also have this flicker on my DC locomotives with LEDs installed. Clean track and wheels will only go so far to alleviate the issue.
The capacitor sounds like a good idea. I have not tried it yet. Didn't even know there was such a thing as a non-polarized capacitor.
Sounds like a future project. Until then, I've learned to live with the flicker. I feel your pain, Johnny.
Does the schematic mean the capacitor goes on the common light wire? I never could read those things. :)
Regards,
Jonathan
it gets wired exactly as shown. The wires to the LEDs are as long as need to get them in the right locations for your loco. If that was an old style schematic, there would be big black dots where the wires cross or touch, indicating a connection.
Here's an example of a nonpolarized .5uf capacitor that will work fine for this circuit: http://www.amazon.com/CAPACITOR-POLYESTER-FILM-RADIAL-POLARIZED/dp/B007Z7JE6W (http://www.amazon.com/CAPACITOR-POLYESTER-FILM-RADIAL-POLARIZED/dp/B007Z7JE6W) Also available from many other sources, so you might want to shop around for the best price.
Len
Interesting, way back when, when I asked for direction here on directional lighting, I was told it was not necessary to use any thing other than the LEDs and appropriate strength resistor. So that is what I have been doing w/o issue outside of the hardly noticeable "flicka" and again, only when the wheels are dirty. Once clean, no issues. And only one model, an SD9, does the flicka happen with any frequency. Again, this is not a split frame loco; don't know if that makes any difference or why it even would.
And on 2nd thoughts, I think it was Joe Satnik who once explained the electrical reason(s) for the flicka effect.
Quote from: Len on October 22, 2015, 10:52:39 PM
Here's a circuit for a basic directional light set up using LEDs. The capacitor is nonpolarized to deal with the polarity reversals when changing direction.
(http://www.personainternet.com/bkingsmill/train%20stuff/SCH%202%20LED%20LOCOMOTIVE.jpg)
Len
Thank you for sharing this.I have seen that the opposing LED flicker will eventually blow the led and this has happened to me over time.
Quote from: brokenrail on October 23, 2015, 10:37:14 AM
...the opposing LED flicker will eventually blow the led and this has happened to me over time.
Has never happened to me. ???
Over how long a period of time did this take to happen?
Typical ceramic bypass caps used in Bachmann DCC locos when I saw the circuit diagram.
The Mylar ones have little better specs as I recall.
I use to have lots of both from stripping old circuit boards for electronic experiments.
Rich
There is a trick I like to tell my customers, especially with LED lighting; and that is for them to crack the dimmer back a bit. This will provide a "cushion" for the voltage to bump up against.
I have 65 watt lamps in recessed cans in my house that have been there for (no kidding!!) some 28 years. The dimmers are cracked back just a little. You don't even notice the difference. If you can do likewise-that is, drop voltage a tad- with LEDs in trains, the chances of burning an LED out is really diminished. Don't forget; the lighting here is a resistive load, mostly because of the resistor; therefore, the load is directly proportional to your voltage. The other thing is that LEDs are not a true light, but light is a product of the transconductance, which is why you need a resistor in the first place; otherwise, with no resistor, the LED will burn out as it will be operating under a 'short circuit' condition. utilize a threshold voltage; below that, the LEDs will not operate.
Rich C.
Rich, JA is using a resistor w/his LED(s) and stated he is still managing to burn out the LEDs over time.
Brock;
Jim, the only way I know of to surely burn out an LED is to push a straight voltage through it-with no dropping load between it and a complete circuit-in short, a short to completed; EG: voltage going through the LED, and straight through to the other terminal of the source sans resistor. If you have monkeyed around enough with these pups, you will see that if you start from zero volts, there will be no completed circuit via the load; this is because of the low voltage not being able to get through that resistor. If you increase the voltage to where the 'light comes on', then the circuit will have achieved a threshold voltage and moved higher enough to complete the circuit via the whole load.
A decoder will (should) have the equivalent to a resistor between the LEDs and positive. If you are able to check out that part of a decoder, I think what you will find is that there is a short somewhere across to the positive terminal of the source. This, also may account for the "blink-blink" business. I can't tell you that without playing around with that decoder.
OH...Amd justso you know, I am only a dumb old electrician-not an electronical engineer...
Rich C.
The OP said he's running straight DC, no decoder involved. I'm wondering what power pack he's using? Tthe output on some isn't all that clean, and without the bypass capacitor the AC component may be hitting the LED with significant reverse current. Over time that could cause the LED to break down.
Len
Cormier;
Rich, reading is fundamental.
Also, hope you don't feel you need to remind me of your electrician background, since you know, that I am fully aware of that. ;)
Quote from: Len on October 24, 2015, 05:42:50 PM
...without the bypass capacitor the AC component may be hitting the LED with significant reverse current. Over time that could cause the LED to break down.
Len
Len, would this not also show up though in a jack rabitt jump of speed by the motor?
Jim; I know, I know. I knew when I wrote it I would hear back. Oye! How you took that was not in the context in which I meant it to be taken. There are other readers on this site besides you and me. So don't worry, kid...
I hope I got my message over though. As I said, I am no electronics techie-just a dumb old electrician. I know very little about electronics; and the fact that is changing faster than I can keep up with it makes me happy I am retired-sort of.
HOWEVER...I still do know my electrical theory-and they still are the same, after all; so I guess that makes it all better, huh...?
On another note; I got some more Bachmann parts and will be "creating" this winter. It is fun. I am retired-and happy..(just so you got it the second time...ha ha)...
Rich C.
Len, would this not also show up though in a jack rabitt jump of speed by the motor?
Jim;
This would not necessarily happen because of the variables involved here. If there is a high-resistance short-or connection-then there could be some different things happening. What puzzles me is that this is a DC circuit; so like Len said, if he is using a different xformer, then stuff like this could happen.
Rich C.
Jim - More likely a motor running hotter than it should, rather than a jack rabbit start. Somewhere I've got some O-scope pictures I took of various power pack outputs 10 or 12 years ago. If I can ever find the box they're stashed in I'll have to scan them and make postable .jpg's. They're an eye opener regarding the so called "DC" output of a lot of low end power packs that generally used one or two small disc capactors for "filtering".
Everyone thinks of the output of a power pack as being a nice flat DC line. The reality is, without the better filtering of more expensive power packs, what you're actually getting is either the upper or lower half of a sine wave, depending on where the direction switch is set.
The nice neat drawings of half or full wave rectified AC you see in books show the AC neatly chopped off at the crossover point by the rectifier. The reality is, there's a certain amount of "overshoot" at the crossover point, which makes filtering even more critical when LEDs are used with low end power packs. It gets even worse with those "Pulse Power" packs which were made for a while to try and overcome starting issues with old style open frame motors.
Len
Quote from: jbrock27 on October 24, 2015, 06:58:13 PM
Cormier;
Rich, reading is fundamental.
Also, hope you don't feel you need to remind me of your electrician background, since you know, that I am fully aware of that. ;)
Offensive material removed again. I will try to be more sensitive. lol
Rich
Quote from: richardl on October 25, 2015, 01:28:13 AM
Offensive material removed again. I will try to be more sensitive. lol
Rich
lexxon/RichG/richardl, is your name
Rich Cormier as well? :D I was not even addressing you, LOL !!
Quote from: electrical whiz kid on October 24, 2015, 07:40:38 PM
There are other readers on this site besides you and me. So don't worry, kid...
Rich C.
Rich(
C), I know that and I am certain that many recall that factoid about you since you have wrote it enough times. No worries. It just appeared by the structure of your post you were addressing me. I am glad we understand each other.
But speaking of understanding, while you have a great understanding of electrical properties, your first post did not reflect an understanding of what
JA (the OP) had already said he was working with, so your first comments were really coming out of left field and of little to no value to assisting him with his problem, my friend.
Len I thank you and
Rich (
C) too for the expansion on what you meant by a possible power pack issue. Gives more reason to delegate the "cheap" power sources to running lights or other accessories and save the good stuff by MRC for running DC locos :)
Until I can find my O-scope pics, check out this page: http://sumidacrossing.org/LayoutElectricity/ModelTrainPower/PowerPackTesting/ (http://sumidacrossing.org/LayoutElectricity/ModelTrainPower/PowerPackTesting/)
Even some of the newer packs have a certain amount of "noise" and "over shoot" on their outputs. I have to admit to being a bit surprised by the output on a couple of them.
Len
Thanks for the info Len, I will check it out.
For those of you following this thread and aren't all too familiar with what is being discussed. Len meant that the cheapo xformers lack a lot of parts necessary to rectify and smoothly filter down AC to get a good DC current flow. How this is accomplished is analogous to water flowing in a tube. If you have variations in pressure and volume, and want constant pressure (DC ), you would install devices to make volume and pressure constant.
In electricity, volume is equivalent to current (amps), and pressure is EMF (a fancy way to say voltage)... In electricity, AC would look like a standard sine wave on a chart. If you take out-say-the bottom half of that wave, you have half-wave voltage-or rectification, if you will. Now, there are ways to use that negative component. One would use capacitance, which would act like a pump in our water analogy. This, combined with some one-way valves (diodes), and some resistance-and if you want to get fancy, inductors (coils) would give you a fairly smooth-acting appliance. Now, all of this would be done on a high-grade transformer , and it would (supposedly) leave you alone. As Garfield said; if you want to have class, you gotta spend money... This was a pretty basic explanation, but using it, I tried to convey some basics just to get you the idea.
Rich C.
Quote from: Len on October 25, 2015, 10:52:06 AM
...check out this page: http://sumidacrossing.org/LayoutElectricity/ModelTrainPower/PowerPackTesting/ (http://sumidacrossing.org/LayoutElectricity/ModelTrainPower/PowerPackTesting/)
Len
Len, I have been reading this. If refers a lot to "modern DC motors" and the ones that are not as being ones that are impacted. So, it begs the question, what defines a "modern DC motor"? Gotta think Bachmann Plus motors fall into the "modern" category. Agree?
jb - Agreed.
I wasn't too concerned with the motor discussion on that page. I was mainly interested in the O-scope pictures showing the transients and overshoots that can do "not good" things to LEDs if not dealt with properly.
Len
Len;
I am the first guy to say I know diddly about LEDs, but would an inductor and a cap in that LED/resistor circuit, if used right, tend to smooth out the voltage, and restrict the transients to a minimum? I find similar problems in dealing with the new lighting systems out there. As you know, the emphasis today is on using LEDs to replace other forms of lighting; but, there are load considerations, effects like 3rd harmonics, etc to deal with. In industry, one would approach this differently than a modeler, but it is essentially the same thing; AC being rectified to DC.
Rich C
The .5uf cap in the diagram I posted earlier eliminates, or at least cuts to to a reasonable level, the transients that would damage an LED used by modelers.
I don't know enough about the new LED bulbs for household use to comment on them. Except to say my electric bill went way down when I switched to LED bulbs throughout the house.
Len
Len;
I didn't catch that post. OK. We are thinking along the same lines. The scope would show a sine wave (AC), and transients as well. I learned the basics of the scope in Air Force tech school at Chanute; Having done so, I have only had occasion to use one twice-in fifty years... Boy...am I an expert, eh?
Actually, I have in my collection, a myriad ménage of gauges, meters, et al that would work for me probably for another hundred years... Actually, this field is constantly morphing at an exponential rate. The 2014 NEC/NFP70 is bigger and better than ever...
even with those thinner pages... There is now stuff on generators, PV systems, that was never in there until now. The hard-cover issue costs around 100 dollars. I am glad I am "retiring"...ANd I do not envy the "young'ns".
(tired old) Rich C.
Quote from: Len on October 27, 2015, 07:19:22 AM
I was mainly interested in the O-scope pictures showing the transients and overshoots that can do "not good" things to LEDs if not dealt with properly.
Len
This is not addressed in the findings/report, correct? You are drawing this inference from this guy's readings on his O-Scope, correct?
Quote from: jbrock27 on October 27, 2015, 04:53:38 PM
Quote from: Len on October 27, 2015, 07:19:22 AM
I was mainly interested in the O-scope pictures showing the transients and overshoots that can do "not good" things to LEDs if not dealt with properly.
Len
This is not addressed in the findings/report, correct? You are drawing this inference from this guy's readings on his O-Scope, correct?
Yes, as I explained above, I pointed to the page because of the O-scope pictures showing the transients. They are very similar to the O-scope pics I tood several years ago. Pointing to them saved me the hassle of digging mine out, scanning them, and posting them here to show what I meant by 'transients' and 'overshoot' on power pack outputs.
Len
Does it provide any explanation then, to why I don't have the problems the OP (JA) is experiencing, since I am using a "modern" motor and have my LEDs (with resistors inline) connected directly to the contacts on the "modern" motor? Another way of saying it, does the modern motor being used in conjunction with the LEDs reduce the impact of these transients and overshoots?
If the LEDs and resisters are wired in parallel with, and directly to, the motor it will reduce the current, and spikes, getting to the LEDs. The inductive load of the motor may do some smoothing, but not as much as a capacitor would. It's still definately better than going directly from one rail pickup, through the resistor to LED1, directly to LED2, then back to the other rail pickup with no capacitor.
Best scenario, wire them in parallel with the motor and use a capacitor.
Len
Quote from: Len on October 28, 2015, 05:25:50 AM
If the LEDs and resisters are wired in parallel with, and directly to, the motor it will reduce the current, and spikes, getting to the LEDs. The inductive load of the motor may do some smoothing...
Len
Thanks
Len, this would explain why I am not having problems.
Len;
What type of DC motors is Bachmann using in their product? I know there is a variation in design per model requirements, but the type should be essentially the same, no? Using an ammeter and running [them up] under no load, they seem to be nice and smooth, no sudden drops, spikes, etc.
Rich C.
Modern, can.
Jim;
I guess I didn't make myself clear. Was this a standard construction-EG: Commutator, brushes, etc-or was it something on the order of brushless motors. Brush-less motors are a pretty good proposition. The less parts, generally the better off you are. OH, BTW: Bowser and Precision Scale both have those tender trucks I was looking for.
Rich C.
Ahhh. Sorry Rich, can't help there. If I had to guess and this is just a guess, I would say no, they are not brushless.
all Bachmann locomotives I have worked on, including the split frame designs, have motors with brushes. the usual setup is that these motors have a metal cap over the brushes, and a strap running from the caps that contacts the frame. in my decoder installations I have removed these straps and soldered the motor leads directly to the caps (after removing them from the motor of course)
the setup is very similar to an athearn motor.
Jeffery;
I have been looking into coreless and brushless motors for a while. I find them intriguing as a plausible venue. I know coreless motors are used in-at least one application-in servo systems and (GASP!!) drones, but would like to hear from maybe you, Hunt and others with some knowledge on them, with your take on this subject.
Thanks in advance.
Rich C.
Quote from: jward on November 01, 2015, 10:19:26 AM
the setup is very similar to an athearn motor.
In concept and operation, yes absofruitly. But I have never taken a Bachmann can motor apart and have not witnessed anyone being able to do that either. Different story with the other brand you mentioned. Makes for maintenance and/or repair possible and easier, particularly if something like, brushes, armature, motor housing need replacing.
Rich, I wish you well and luck in your endeavor to have such a lively discussion here, however unlikely given our hosts lack of employ of those kinds of motors and therefore, lack of tolerance for such discussions.
Quote from: electrical whiz kid on November 04, 2015, 07:57:34 PM
. . .
I have been looking into coreless and brushless motors for a while. I find them intriguing as a plausible venue. . . .
Rich C.
Way Off Topic of this thread. So in short -
One of the "Keys" is the torque you get from the motor size and weight- offset by its cost Keep in mind, the controller to keep a brushless motor running can be more expensive than the motor.
As you probable already know, a lot of info (along with some misinformation) about coreless and brushless motors in the R/C hobby sites.
Jim;
It wasn't really an endeavor, just looking for some feedback as a starting point. If you like, I can retract it...
Rich C.
Quote from: electrical whiz kid on November 05, 2015, 07:23:22 AM
If you like, I can retract it...
Rich C.
Oh no
Rich, certainly not.
I am in full favor of free, diverse an open discussions. You have to know what I was implying, don't you??
Quote from: electrical whiz kid on November 05, 2015, 07:23:22 AM
It wasn't really an endeavor...
Rich C.
Hmmmm, what is your definition of 'endeavor' then?
jb,
the motor brushes and springs can be accessed by prying loose the copper caps that hold them in place with a small screwdriver. the brushes are in the same spot on the motor as the brushes on an athearn motor. the caps snap into place when you are done working on the brushes.
Thank you Jeff.
Have you had reason in the past to replace the brushes? If so, does Bachmann or someone else make replacements?
Thanks again.
no I have never had to replace the brushes on any of my Bachmann units, but I do remove the caps to solder the decoder leads to them when I convert them to dcc. better to remove them than to try to solder in place and risk melting the motor housing.
Jeffry; good thinking. There is some pretty delicate construction on these and other motors of this size. Logic would dictate there being plastics and epoxies in place of a lot of previous parts made from Bakelite (R) Micarta (R). etc.
The stuff I usually work with is a bit bigger-like 100+Hp., so I still have to be careful-sometimes for the exact same reasons.
RIch C.
Quote from: jward on November 06, 2015, 02:16:57 PM
...I do remove the caps to solder the decoder leads...
Makes all the sense. Thank you for getting back to me.
Just outta curiosity and in follow up to the other part of my question, anyone know if Bachmann sells replacement brushes for their motors? Took a look on the Parts Page, didn't find any listed there under HO.
Jim;
you may have to get in touch with [their] jobber(s). Quite obviously, Bachmann wouldn't get too involved with parts of this nature-brushes, motor parts, etc;, given the cost of the motors; as well as the fact that other [suppliers will generally stock] these parts, and do so cheaper than Bachmann might, considering the final logistical say of the numbers.
There are many MFGs of motors. Some are good, some not so. It would be incumbent upon you et al to peruse info at hand to find what will work for you. These last several posts brought me back to my ninth year, when I walked into a hobby shop and found a Stewart DC motor kit. I thought this was an interesting kit. It was.
Rich C.
Quote from: electrical whiz kid on November 07, 2015, 10:24:46 AM
you may have to get in touch with [their] jobber(s).
Rich C.
What ???
Quote from: electrical whiz kid on November 07, 2015, 10:24:46 AM
Quite obviously, Bachmann wouldn't get too involved with parts of this nature-brushes, motor parts, etc;, given the cost of the motors.
Rich C.
What's so obvious? Other manufacturers
do get involved with making such parts and their motors are comparable in cost to Bachmann's. But I am not asking about motor brushes made for other manufacturers' motors, or other "mfg's" motors, I am asking about the availability of replacement brushes for Bachmann motors. So why the tangent?
I take it by your response, you don't know the answer then to my query?
A 2mm diameter pencil lead cut to length may work. The Atlas 707101 Brush Set also looks pretty close, but you'd have to check availability. They go out of stock fairly often.
Len
Thank you for the input Len. I recall reading at one time, how you used a couple of Lionel brushes, cutting them with a track saw if I remember correctly, to get them to the correct length to use in a pancake motor.
It is looking more and more like the answer to my question is simply, "no".
I'd say that's a fair assumption. The only small brushes I could lay hands on for my repair shop came from Athearn, Atlas, and Kato. If I couldn't find one of those that would fit, I fell back on various size pencil leads from the local office supply store.
And yeah, cut down Lionel brushes worked in the pancake motors. Although, there are a couple of on-line sites claiming to have pancake motor brushes. I've never used them, so have no idea if they work or not.
Len
How did you form the curvature for where the brushes fit against the commutator?
I usually used a small "diamond coated" jewlers file. Sometimes I put a small diameter wood dowel in the mini-drill press, slid the lead into a small brass tube to keep it from snapping off, then held the end of the lead against the dowl using gentle pressure.
Len
Thank you.
Seems like a job one should be able to get someone in CHINA to do for much less, both in time and cost :D
Your welcome. And the drill press was turned on so the dowel was spinning! :D
Len
Len; I assume the dowel was the same diameter as the commutator... If they are mis-fit, then bad things might happen to an otherwise very nice motor.
Rich C.
Quote from: electrical whiz kid on November 10, 2015, 07:27:00 PM
...bad things might happen to an otherwise very nice motor.
Rich C.
I would like to point out, the reason for going down that road to begin with was for a lack of availability of replacement brushes, so if one is in a position of having to replace the brushes, the motor is not going anywhere, anyway, so nothing ventured, nothing gained right? Plus, what just happened to the "do what makes you happy" philosophy? :D
Quote from: electrical whiz kid on November 10, 2015, 07:27:00 PM
Len; I assume the dowel was the same diameter as the commutator... If they are mis-fit, then bad things might happen to an otherwise very nice motor.
Rich C.
It's not super critical, it's only graphite after all. You can leave the end flat and it will wear to the curve of the armature on it's own.
Len
Jim;
Yep; you are right. You do what makes you happy...
Rich C.
Rich, it is you who are right and I agree, it's an excellent philosophical approach to life :)
Quote from: Len on November 11, 2015, 04:31:34 AM
You can leave the end flat and it will wear to the curve of the armature on it's own.
Len
But in the meantime, doesn't that create a lot of noise when the motor is running, until they take the shape of the curve? Conducta Lube can only do so much.
Jim;
'Twas not my response. I would have said to find the dia. of the commutator, and this is what you would reference the brushes to when shaping.
In industrial applications, as in with AC synchronous and DC motors, the brushes are usually pre-shaped as per the dia/commutator-and then completed a run-in with no load. If this is not done, then significant losses of efficiency, as well as excessive heat and damage to the commutator could result. I would presume that, on a much smaller scale, the same set of mechanics would apply.
Rich C.
Quote from: electrical whiz kid on November 11, 2015, 04:06:43 PM
Jim;
'Twas not my response.
Rich C.
I know that
Rich. This question:
Quote from: jbrock27 on November 11, 2015, 09:01:47 AM
But in the meantime, doesn't that create a lot of noise when the motor is running, until they take the shape of the curve?
, was put to
Len.
This all goes back to him having to make brushes to fit a motor that brushes were no longer available for. Since I already knew that brushes are pre-shaped to the curve of the commutator, I was asking him if they make a racket until the brushes wear to the curvature of the armature on their own.
If all else fails, and one cannot find replacement brushes, "rough"-form what you have with whatever means you have that will work; then, once you have them more or less to shape, install them and turn the rotor by hand-slowly-until any drag, roughness, etc. stops. If the rotor hangs up-stop! Those commutator segments are delicate! Then, when you put power to the motor, run it slowly until it is in smooth operation. This all should be common sense, but it doesn't hurt to review.
RIch C.
Thanks Rich. What you say, certainly makes sense, although I find Athearn commutators to be very sturdy and not very fragile. But here's is one problem with the theory to just run the motor till it smooths out the edge of the commutator; I have an Athearn motor that no matter how much it gets run forward and back, it is making noise at the brushes and commutator running backwards (less in forward). The brushes are in correctly, everything has been cleaned and polished. It runs smooth but still makes what I would call a coffee grinding noise when running backward. No amount of Conducta Lube has helped. Flywheels have been removed and nothing is hitting the shell.
I have tried getting some help here behind the scenes here, but so far it has been a discouraging noise to get rid of.
Quote from: jbrock27 on November 11, 2015, 09:01:47 AM
Rich, it is you who are right and I agree, it's an excellent philosophical approach to life :)
Quote from: Len on November 11, 2015, 04:31:34 AM
You can leave the end flat and it will wear to the curve of the armature on it's own.
Len
But in the meantime, doesn't that create a lot of noise when the motor is running, until they take the shape of the curve? Conducta Lube can only do so much.
No, it shouldn't make a lot of noise if the ends of the brushes are flat to start with. If there is a lot of noise, I would disconnect the drive shafts and see if it's still noisy when power is applied. If the noise goes away without the drive shafts, I would be looking at the gears and bearings supporting the gears. Possibly the ends of the drive shafts themselves.
If the motor is real noisy with the drive shafts disconnected, I would look at the armature shaft bearings and make sure they weren't worn. Over time the bearings can wear, allowing the shaft to develop a minute wobble, accellerating the wear as the motor is run even more. Sometimes, if the loco was ever dropped and there are heavy flywheels, the armature shaft itself can be very slightly bent.
The only time I've heard of graphite brushes causing loud noises, was when they were worn down to a thin disk and got tipped in the brush tube.
Len
Quote from: Len on November 14, 2015, 06:21:48 AM
No, it shouldn't make a lot of noise if the ends of the brushes are flat to start with.
Len
Thanks for the suggestions
Len, but no, the brushes have the curved ends like they are supposed to and fit well on the commutator. They also have plenty of "meat" on them, so they are not worn to nothing. (I frankly don't know how they would even work if the commutator ends were flat.)
Been down most of this road prior:
Quote from: Len on November 14, 2015, 06:21:48 AM
disconnect the drive shafts
Len
...done that, the only noise is the motor running and it's not much noise. And very little vibration when running.
Quote from: Len on November 14, 2015, 06:21:48 AM
armature shaft bearings and make sure they weren't worn...shaft to develop a minute wobble...armature shaft itself can be very slightly bent.
Len
...nope, all good
Quote from: Len on November 14, 2015, 06:21:48 AM
loud noises
Len
Let me just clarify if I may, and this is the difficulty that can be had when trying to describe the types and volume of noises; it is not what I would categorize as "loud". When I say "coffee grinder", I mean in type of noise but not in volume. It is just enough noise to be annoying bc it is alot more noise than silent, if you get my drift. No problems with the drive-line, everything runs true. Even trimmed the brush springs a little. I have many other motors of the same type that are A LOT quieter. Added weight to the shell even but it makes the same noise with the shell off, just at a lesser decibel level. It really has me puzzled. Trust me, if it was simple, I would have figured it out and would not be writing about it at this point. ;)
Is there any arc pitting or burrs on the commutator segments? From what your saying, it's about the only thing left I can think to look for.
Len
Len;
Yes, that is true.
Arcing would be obvious if a line of sight is available. If things are running hot-as in brushes worn down, there could be some smoking as well as excessive arcing. This would be characteristic of all series wound motors. If the brushes aren't conformed to the commutator, then you can have a poor connection, resulting in high resistance.
You are also right about disconnecting the motor from the drive train. Motors shouldn't have more than a slight somewhat high-pitched hum to them. If there is growling, then my guess it would be brushes/commutator are either misaligned or worn.
At tech school, Chanute AFB, they taught us to "isolate, locate, and eradicate".
Rich C.
Quote from: Len on November 14, 2015, 08:48:08 AM
Is there any arc pitting or burrs on the commutator segments?
Len
I knew you would ask me that and forgot to include that info above, I got to so much typing. No, none. And when I first got this loco, indeed 2nd hand so I don't know it's history and certainly can't ask it (by the looks of the brushes, motor, etc. looks like it was hardly if, ever, run, so doubt strongly it was ever dropped or abused and nothing upon complete dis-assembly pointed to that) I polished the commutator, so no burrs. I even put in enough thrust washers to clean up the amount of front to back "play" it had, it has some play now, about the width of 1 and a half thrust washers, maybe even less than that.
Quote from: electrical whiz kid on November 14, 2015, 09:33:42 AM
If things are running hot
Rich C.
Nope, they are not.
Quote from: electrical whiz kid on November 14, 2015, 09:33:42 AM
brushes worn down
Rich C.
Nope, see above, they are like brand new.
Quote from: electrical whiz kid on November 14, 2015, 09:33:42 AM
the brushes aren't conformed to the commutator...brushes/commutator are either misaligned or worn.
Rich C.
They are, perfectly and they are neither misaligned or worn.
Quote from: electrical whiz kid on November 14, 2015, 09:33:42 AM
isolate, locate, and eradicate".
Rich C.
Rich, can't tell you how many times I have already done that. This is not my first rodeo with these.
Keep in mind, it makes less noise in one direction than the other.
Barring all else and given my thought that this thing was hardly ever run, is it possible there has not been ENOUGH run time and therefore wear of the brushes at the point where they meet the commutator and over time, with running, it will quiet them because there is something about the graphite surface of the brushes that makes them nosier when new? This is pretty much with what I am left with thinking. All I have done is let the motor run for several minutes in each direction at different speed and run it back and forth on a test track. I would say at most, an hours worth of run time.
Jim;
You nailed it. "when the brushes are new"! Nothing 'brand new' is going to be a perfect fit; hence the run-in time in which the brushes conform to the "run-out' of the commutator.
As far as more noise in one or the other direction, this can be attributable to uneven deposits of worn graphite in the segment splits, or anything so miniscule as such, that it makes no difference. To my way of thinking, you will have it good once everything wears in. This is why, in a previous post, I mentioned turning the rotor by hand when this modification is first done. They are tiny and delicate.
Thrust washers are a good idea, as that reversing motion has a tendency to move the rotor fore and aft, maybe causing premature wear in the process.
Rich c .
.
Okey doke, I will see if it quiets down any after some considerable run time.
Just for ghits and siggles, I had disconnected the fore and aft drive parts again and ran it on the track (w/o it going anywhere) both in forward and reverse, several more minutes at 30% power each direction and while it runs smooth in both directions, it does make a slight more noise in reverse.
yep; That would probably occur, Jim, as 'forward' is the predominant direction, wear patterns would occur in it's favour, and reverse would tend to 'fight' it, thus the noise. one sure way of checking things out is to measure either current or watts. A neat trick I learned from an old salt (when I was young...) is to take a section of an empty toilet paper roll about an inch or so long, do ten wraps of wire around it, secure it with a piece of tape and hook up one end to the load, and the other to the source. What this setup does is to 'amplify' the current reading on an amprobe X ten; and I am sure that it would do the same with an ammeter with too high of a reading. Thus a reading of 5 amps would actually be .5 amps. This has worked for me many times, either AC or DC.
Rich C.
Quote from: electrical whiz kid on November 16, 2015, 08:30:47 PM
as 'forward' is the predominant direction, wear patterns would occur in it's favour, and reverse would tend to 'fight' it, thus the noise.
Rich C.
I understand what you saying, but still don't understand why that would be the case as the curvature of the commutator is the same, whether it is spinning clockwise or counter clockwise (forward or reverse) and it is still spinning against both brushes when running in either forward or reverse, so why noise in only one direction?
Jim;
When the commutator revolves in one direction more or less all the time, a certain amount of "wear in", minute deposits along one side of each segment, accumulated crud, etc. will occur, causing mechanical resistance to that reversing direction. I think it works along the same lines as if all you made were right-hand turns in your car, wear patterns on the tires would indicate some unusual occurrence along the same lines here. It is just my thought, for what it is worth.
Rich C.
A good example Rich!
Quote from: jbrock27 on November 04, 2015, 08:27:22 PM
Quote from: jward on November 01, 2015, 10:19:26 AM
the setup is very similar to an athearn motor.
In concept and operation, yes absofruitly. But I have never taken a Bachmann can motor apart and have not witnessed anyone being able to do that either. Different story with the other brand you mentioned. Makes for maintenance and/or repair possible and easier, particularly if something like, brushes, armature, motor housing need replacing.
Rich, I wish you well and luck in your endeavor to have such a lively discussion here, however unlikely given our hosts lack of employ of those kinds of motors and therefore, lack of tolerance for such discussions.
They come apart quite easy by just straightening out the can/housing pinch.The hard part for me was the flywheels are tough to remove, anyhow without a puller ,but a vice lined with rubber to hold the flywheel and a good punch on the end of the motor shaft does the trick.
So what reason did you have to pull one apart?
gp 30 or 35 motors they had some noise in them running, and when you spin by hand, also I found the brushes were stuck in.Springs came out and looked ok. Found out Bachmann does not sell replacement brushes or springs,,Had one of there 70 toner can motor aprart for the same reason ,found that one uses a epoxy to hold the magnets in ,but it did not hold and the magnet dropped hitting the armature.That was a easy fix even if you lose a spring.They look like they use the springs that Are OFF kadees or the ez mate couple rs
Johnny Adam.
Thanks for responding. I have a somewhat noisy Plus GP35 that brought me to this Board for a solution some time ago. And thanks for confirming a question I had a few weeks ago-whether Bachmann sold replacement springs and brushes.
So I follow you, in the end, did you have success with what you were trying to accomplish?
Some success on those that did not have distorted brush housings.They were clean and not distorted from heat,but it would seem they were pressed in there housings crook-id. They all had very strong magnets for there size.
Broken Rail, Brock, et al;
I would advise care on the issues of magnet replacement. The old saw "enough is enough" should apply here. Too big a magnet will tend to cause more problems. Keep in mind the terms; eddy current, hysteresis loss, flux density, reluctance. All are-or should be-considerations when dealing with modification of an inductive load.
Rich C.
Thanks for getting back to me brokenail.