Large Scale Central

Chuff Magnet Question

Electronics Power and Sound
#1

I blew the internal fuse I installed when converting my Bachman Porter to R/C so I needed to open it up. While I am in there I want to improve the chuff triggering for the Phoenix P8. When I did the original conversion I used the built-in drum/finger triggers…

This proved to be less than satisfactory at anything faster than a crawl as the brass fingers tend to float. I have plenty of left over reed switches and can come up with magnets. Before I begin I need to answer a few questions.

The current system uses 4 triggers per revolution and the P8 is programmed for 1 chuff per trigger. Would using two magnets and reprogramming the Phoenix for two chuffs per trigger give better results than 4 magnets?

If I can dig up some very thin magnets I can use the existing drum. An alternative would be to drill a hole behind a wheel and glue magnets to the back side of the wheel. The drum is easier to access so I’m leaning that way. Any opinions?

Thanks! I need to finish this quick as I want to bring it to York.

#2

That drum looks to be about half the size of the driver wheel diameter, so 2 should be plenty. I would just use 2 and see what it sounds like. Or just have a reed switch on either side.

#3

2 magnets on the axle, with 1 reed switch, will give you 2 chuffs per revolution.

#4

magnet

powerful magnets too small maybe? search for neomidium magnets

for more sizes

Bill

#5

Thanks all. No time to source magnets. I had two in stock left over from one of the Phoenix kits I bought years ago. So two it is. I decided to mount them on the drum, but with very little clearance above the axle I needed to recess them a bit. Plenty of room to mount the reed switch where the fingers are in the photo. Hi-temp hot glue looks like the best attaching method. I’ll post some pictures tomorrow.

I think I would prefer 4 chuffs per revolution but that can be done with a setting on the P8 using two magnets.

#6

Installed and working (http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-smile.gif)

Step one was to drill the drum to allow the magnets to be recessed a bit…

Next I attached 2 magnets with 5 minute epoxy…

Once the epoxy dried I used a tone test continuity meter to determine reed switch placement. I wasn’t getting reliable triggering so I removed the original bars from the drum thinking they were interfering. Unfortunately that made no difference. I decided the problem was that my meter was just not fast enough to detect rapid state change - so I just used it with the drum static to determine the gap setting. Once I was happy that the reed would close I used high-temp hot glue to hold the reed switch in place…

Once the glue cooled I ran a functional test using the sound board and was very happy with the result. I just need to change the programming to 2 chuffs/trigger and I’ll be all set!

While I have the loco open I’ll replace the very old frame style DC charging jack that I suspect caused the short with a modern coaxial jack. Then I need to try and stuff all this wire back in the shell (http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-surprised.gif)

#7

Got it buttoned up and programmed for 2 chuffs per trigger. It has never sounded so good! Well worth the time invested.

#8

Do a video! (http://largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-wink.gif)

#9

Cool.

#10

Joe Zullo said:

Do a video! (http://largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-wink.gif)

Your wish is my command (http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-yell.gif)

#11

As you have found, the mechanical triggers are usually crap. Not only do they float, but often they will bounce too, and give you too many chuffs.

Glad you got it the way you want.

Greg

#12

Jon,

That sounds really good. Nice job, and thanks for the video.(http://largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-smile.gif) Is this loco track powered?

#13

Joe Zullo said:

Jon,

That sounds really good. Nice job, and thanks for the video.(http://largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-smile.gif) Is this loco track powered?

No problem. R/C with on-board battery. Using Del’s RailBoss Hobby, Spektrum receiver and a Phoenix P5 in the boiler and two 7.4 lithium packs in the tanks wired in series for 14.8V. Control from a Spectrum DX5e 2-stick radio. You can see some of the gear in a post above.

#14

Greg Elmassian said:

As you have found, the mechanical triggers are usually crap. Not only do they float, but often they will bounce too, and give you too many chuffs.

Glad you got it the way you want.

Greg

I agree. I was lazy when I first converted this loco and thought I could get away with the factory triggers. Initial tests with the loco open sounded good, but soon after it went into service it started acting up and dropping chuff at anything above a crawl. Now I get nice distinct chuff at any speed that is timed nearly dead on with piston position.

#15

Daktah John said:

Joe Zullo said:

Jon,

That sounds really good. Nice job, and thanks for the video.(http://largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-smile.gif) Is this loco track powered?

No problem. R/C with on-board battery. Using Del’s RailBoss Hobby, Spektrum receiver and a Phoenix P5 in the boiler and two 7.4 lithium packs in the tanks wired in series for 14.8V. Control from a Spectrum DX5e 2-stick radio. You can see some of the gear in a post above.

Thanks Jon. I have one of those Spectrum Porters also. I’ve been thinking of converting it to battery RC using the Crest Revo TE. I see you stuck the batteries in the side tanks and removed the weight. How does it pull now and is the weight of your batteries and radio equipment comparable to the stock weight?

#16

I ended up having to scrap the weight because I couldn’t fit the large RailBoss board, batteries and the sound board in without loosing it. I filled all the domes with lead held in with hot glue and also hid a little more lead in the rear behind the mounting posts. There is a thread here of the conversion from several years ago: http://www.largescalecentral.com/forums/topic/13737/rail-boss-in-a-bachman-side-tank-porter/view/post_id/134799

It pulls pretty well on the flat. I can move 4 Accucraft Fn3 cars around the indoor layout. It usually pulls two Bachmann Jackson Sharp passenger cars on the outdoor and does OK with that on the 4% plus grade. It will occasionally bounce out of the gauge when pulling a heavy load.