I see some photos of Pullmor motors that have 2 small capacitors attached. What is the purpose of these? I assume these are newer style motors compared to the post-war type?
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Noise suppression.
Specifically electrical noise. The AC motor brushes generate a lot of electronic "hash", and the caps are there to suppress most of it.
The capacitors are only used on Pullmor motors that are are attached to TMCC or electronic reverse units. Adding them to a locomotive with an old mechanical E-unit won't gain any performance, fyi.
Postwar motors do not have those capacitors. Nor do older Modern era motors.
One may keep "fuzz" off your tv though. Even digital catches fuzz
gunrunnerjohn posted:Specifically electrical noise. The AC motor brushes generate a lot of electronic "hash", and the caps are there to suppress most of it.
Would it be a good idea to add capacitors to a postwar or early modern Pullmor motor when installing an AC Commander/Railsounds setup?
rickoshay posted:gunrunnerjohn posted:Specifically electrical noise. The AC motor brushes generate a lot of electronic "hash", and the caps are there to suppress most of it.
Would it be a good idea to add capacitors to a postwar or early modern Pullmor motor when installing an AC Commander/Railsounds setup?
Yes. I had to do this with an install I did years ago.
Thanks for the reply, Marty!
what are the specs on the capacitors?
Non-polarized 1uf, 50v.
I understand that the capacitors are there for noise suppression. What affect do the capacitors have on sparking at the brush plate?
I can't answer C.W.'s question. But going a little off-topic, I'll share that Pullmor motors, and the "fuzz" they put on our TV is partially responsible for me becoming a huge football fan.
When I was in grade school during the 1970s, our trains were only set up at Christmas time, and then in the den where the TV was. On Sundays, my grandpop would come over. He and my dad would watch football on broadcast TV. (Cable was still several years away.) We weren't allowed to run trains during the game because it caused "snow" in the TV picture. There was nothing else to do, so my brother and I watched football too. We learned about the game, and today we're both big fans. So I guess it's a good thing that MPC didn't put capacitors on its motors. And I still think of football and trains as fall / winter sports!!
I don't ha
C W Burfle posted:I understand that the capacitors are there for noise suppression. What affect do the capacitors have on sparking at the brush plate?
have, a clue CW.
I do know I had a posting issue the other day. Lucky me the page it showed up on had the exact same subject. (I had the two tabs open, but know where I posted.)
Lots of weird stuff lately, like the split up above. I only typed "have" once and began typing below the quote. But as you see, ain't that way now.
Was this intended for the sparking loco thread, or are you just curious how it would affect that (creates snow I'm sure). (I don't know offhand either, I'd have to think, and it still would likely just be a guess)
Was this intended for the sparking loco thread, or are you just curious how it would affect that (creates snow I'm sure). (I don't know offhand either, I'd have to think, and it still would likely just be a guess)
The post is in the right place. The subject of this thread are those little capacitors that later Modern era locomotives have. My question is whether they have any effect on the amount of sparking at the commutator.
They do not have any impact on the sparking but when that happens, electrical noise is created. While a mechanical e-unit doesn't care, electronic components in TMCC do. The caps help filter out that noise so the electronics don't have to deal with it.
Rickoshay posted:
Would it be a good idea to add capacitors to a postwar or early modern Pullmor motor when installing an AC Commander/Railsounds setup?
AC Commanders include the caps in the kit and provide directions on installing them.
What is the proper technique to install the non-polarized 1uf, 50v. (TVS). A picture and description would be appreciated.
Suggested source for the non-polarized 1uf, 50v. Is this the correct spec?
One capacitor lead to the brush plate, one capacitor lead grounded to the motor frame. A lug under the brush plate screw would work perfectly.
@MartyE posted:They do not have any impact on the sparking but when that happens, electrical noise is created. While a mechanical e-unit doesn't care, electronic components in TMCC do. The caps help filter out that noise so the electronics don't have to deal with it.
Exactly!...
Pat
@Windy City posted:What is the proper technique to install the non-polarized 1uf, 50v. (TVS). A picture and description would be appreciated.
Suggested source for the non-polarized 1uf, 50v. Is this the correct spec?
One minor thing, the 1 uF 50 V cap and the TVS are two totally different items. TVS is covered in many other topics here, a simple search should turn up many threads with good info.
-Dave
