HP 4-6-2 project

dileTTante
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Joined: Wed Jan 06, 2010 12:37 am
Location: Vancouver British Columbia

Re: HP 4-6-2 project

Post by dileTTante »

As a follow up, this locomotive turned into a success. It ran for three hours continuously at train shows last year. It needs repainting and it needs periodic checks for possible loosening running gear but otherwise is reliable. Conversion to DCC is simple as shown in the diagram. It works.
- Terry C
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HP locomotive DC vs DCC.jpg

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AstroGoat760
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Location: Bemidji, Minnesota, USA

Re: HP 4-6-2 project

Post by AstroGoat760 »

That is good to hear. I am currently working on a HP 4-6-2, and as part of the "shakedown cruise", it ran for 6 hours straight, following inspection and full lubrication. No issues noted, other than just needing to complete cosmetic work.

The larger HP Locos (basically anything other than the small x-6-x or x-8-x locos) are a fair bit forgiving of slop in my opinion, which makes them easier to work with.
Life is short, play with TT Scale Trains!

Murad
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Re: HP 4-6-2 project

Post by Murad »

What decoder did you use in this locomotive? I've found 2amp peak LaisDCC decoder that should easily fit HP tender. Hope it will be enough!
WTB any of the HP Products locomotive parts

dileTTante
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Joined: Wed Jan 06, 2010 12:37 am
Location: Vancouver British Columbia

Re: HP 4-6-2 project

Post by dileTTante »

Originally I tried a Digitrax DN143, I think it was. Easy to fit in the tender, rated at 1.25 amp - 2 Amp peak. However it overloaded easily and shut down often. I am not familiar with Lais decoders. It looks like a convenient size but I wouldn't be surprised if your motor overloads the decoder. Maybe your new magnets will help. Please let us know how it all turns out.

Now I have an NCE HO decoder (13s) in the 4-6-2. It is not rated any better than the others but it doesn't overload and shut down. It is larger and requires more room in the tender. Also, a few NCE decoders which I bought turned out to be defective in speed control, so I won't buy any more.

My opinion is that HP locos need HO decoders not N scale decoders.

- Terry C

milwrd1
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Joined: Sun Aug 11, 2013 11:07 am
Location: Vicksburg, MS USA

Re: HP 4-6-2 project

Post by milwrd1 »

dileTTante wrote:As a follow up, this locomotive turned into a success. It ran for three hours continuously at train shows last year. It needs repainting and it needs periodic checks for possible loosening running gear but otherwise is reliable. Conversion to DCC is simple as shown in the diagram. It works.
- Terry C
Terry

If I'm reading your diagram correctly (diagram attached to entry dated 1/15/20), top drawing shows "top" brush connected to the motor frame / Right side Drivers, bottom drawing shows "top" brush isolated from the motor frame / Right side Drivers. Is this correct?

Isolating the brush from the motor frame shouldn't be to difficult, a piece of electrical tape placed between the motor brush and the frame should provide sufficient insulation, if I remember the HP loco electrical configuration correctly. How did you isolate the motor brush from the motor frame??

dileTTante
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Joined: Wed Jan 06, 2010 12:37 am
Location: Vancouver British Columbia

Re: HP 4-6-2 project

Post by dileTTante »

The two motors which I have from HP locos - one steam, one diesel - are configured the same way. I assumed all the motors were made the same. Perhaps I am wrong. On my motors the brushes are both held in a single piece of fibre board which insulates them from the motor frame. This is shown in the two photos attached which were made when I was first working on the model.

Early on, when the decoder was constantly shutting down from overload, I thought at first that there was a short circuit occurring somewhere and I made a great effort to cure that. So in the photo where the motor is out you can see that I put some insulating material (heat shrink) on the motor to make sure the brush springs weren't touching the frame. It may be that in some models the short circuit in one brush is allowed to happen in order to feed track power to the brush. I think that is unlikely.

I was being paranoid about insulation at the time but it appears to me that under normal conditions the brush springs do not touch the frame. On the original models there had been nothing extra done to isolate the other brush from the frame - the brush which was connected to the tender wheel pickup.

At any rate, on my models the brush on one side was connected to the motor frame by a wire.

The photo also shows that I used the screw for the brush holder as a connecting point to get track power from the motor frame back to the decoder. The two brushes being isolated, are connected directly to the decoder.

- Terry C

- Edit -- The photo further back of D Martin's 10 wheeler shows a different arrangement for the motor brushes, so this and my lack of experience will account for the confusion. My apologies.
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DSC04011R.JPG
DSC04072R.JPG

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