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View Full Version : Re-Motor Athearn DD-40



CoolRuehle
09-02-2009, 09:39 PM
I recently purchased an Athearn DD-40 (what a monster) in HO scale. This is the single-motor version, and is noisy and weak pulling a load. I do not know if the noise is because of the motor or the gears, or both. Most likely it's both. Either way, the current motor has to go.

I'd like to re-motor the beast, and I have three options:

1. Outfit it with two more newer motors like the one that's in it (the old blue-box-type) and couple them together. This APPEARS to be the easiest way to go, as the motors snap right into the frame.

2. Outfit it with Athearn Genesis can-type motor and flywheel combo. This could easily be mounteed with double-stick tape (yes, I have seen it done)

3. Outfit it with either single or dual can-type Mabuchi's or other type, attached with DS tape as well.

DCC is definately in it's future. The older type Athearn motors suck alot of juice. Having two in the beast will make it difficult if not impossible to equip with DCC. So I need to keep that in mind.

I am not afraid of mechanical mods like this, it's just knowing the right way to go with the project.

Any suggestions?

(and don't tell me to go buy the Bachmann DDA-40X) :-)

--Jon

UP2CSX
09-02-2009, 11:33 PM
I'd go with the two Athearn motors. The new ones don't draw more than about .4 amps at full slip so a 1 amp decoder should handle it. It will be a much easier conversion to DCC as well and my RTR atherans run fine if they are properly broken in. You have plaenty of romm ot add some extra weight and I would do so. I's seen those with dual motors and a pound of extra weight pulling a 65 car train so I know it can be done with just the Athearn motors.

V&AL
09-04-2009, 01:19 PM
I've seen 2 dual motor DD-40s in DCC. I own one of them, and it has 1 decoder for the 2 stock BB motors. The other one I saw had 2 BB motors... and 2 decoders... from what I here it was a bear to program...

side note: the motors are not coupled together at all. they each spin separately...

ThirteenHorsehoes
03-13-2012, 11:14 PM
looks like I'm reviving an old thread

I found a couple of like-new DD40s ....2 motors no flywheels...

wondering how best to re-power them?......want to have room to add tungsten weight for best pulling traction

has anyone re-geared a DD40?

they'll be used with DCC on 0-2% grades with 33 inch curves

V&AL
03-13-2012, 11:17 PM
I would just drop in 2 standard athearn motors with flywheels... I dont see a big need to re-gear it.

diburning
03-14-2012, 01:00 AM
They're geared for a 12:1 which should give you a decent realistic higher speed operation (Union Pacific used them in high speed intermodal trains. They also regeared some SD40-2s as "Fast 40s" to operate at a faster top speed to match the DD40s)

If I remember correctly, the DD40 had the standard 4-prong Athearn motor mount with the rubber pegs. The Athearn blue box, Athearn RTR, Athearn Genesis, and certain Kato motors all use that same mount so you have a few options here. Just make sure that if you plan on going with DCC that you isolate the motors from the frame. To further make the mounting easier, you can get replacement motor mounts from Athearn or Digitrax (they're the same mounts; Digitrax designs Athearn's electronics) which screw in instead of press in. Kato motors that fit will come with their own own screw-in mounts that is a drop-in installation into the frame.

The thing is, I don't know if you'll be able to lash up two Athearn RTR/Genesis/Kato motors though because I don't think anyone makes a shaft with the hex end on both ends (they all have a hex on one end, and a dogbone on the other) You'd have to splice together two driveshafts somehow to connect the two motors mechanically.

I guess you COULD just have each motor and half of the drive run independently under one decoder if all else fails.

V&AL
03-14-2012, 01:01 AM
I've yet to see a DD-40 with the motors connected... they are all separate. I can't think of a good reason to try and connect them either...

LotoQuestions
03-14-2012, 01:33 AM
I've yet to see a DD-40 with the motors connected... they are all separate. ..
Not true.
You just aren't looking at stuff that is old enough.

My DD40 has the factory original motors joined - they are also corroded beyond repair.:(

take care ,,, ken

V&AL
03-14-2012, 01:38 AM
Metal sideframes?

LotoQuestions
03-14-2012, 02:55 AM
Metal sideframes?

Yep :)

take care ,,, ken

Iron Horseman
03-14-2012, 10:19 PM
I've yet to see a DD-40 with the motors connected... they are all separate. I can't think of a good reason to try and connect them either... The reason to connect them is to keep the power to the rails going at the same speed. Otherwise there is a good chance that one is pulling and the other spinning. Thus one is always fighting against the other and reducing overall tractive effort.

I actually had this problem with the PFM spuds. Did an F7AB set with three of them and they wouldn't pull a thing. Figured out that one of the spuds was turning at a slightly different speed. Replaced the odd unit with another and wow, night and day difference.

V&AL
03-15-2012, 03:10 AM
Huh... I would have thought that the motors turning at slightly different speeds would be a ok, as long as it wasn't drastic. I doubt that if one started to slip the other would keep pulling... But if one wanted to connect them, then they sell packs of athearn drive shafts for not too much. I'll dig up my DD-40 out of storage (need to run it one of these days anyway) and see what would be needed to retrofit it as such...

V&AL
03-17-2012, 02:09 AM
Well, I've learned quite a bit from this weekend... I took my aging DD-40 out to the club (dual motors, unconnected, metal sideframes ancient...)

I'll be rebuilding it at some point, and when I do, she will emerge from the shops with the motors connected. The one would spin and the other barely turn over, then they would swap...

Howie1632
03-17-2012, 08:06 AM
I remotored a DD40 recently and used a Digitrax Dh465 Decoder for both Motors.It works Great.But it running it while pulling 50 cars or more i had problems with the 2 motors connected,it kept throwing a driveshaft.After dis-connecting the driveshaft from the motors,it pulled just fine.

Iron Horseman
03-17-2012, 10:45 PM
I remotored a DD40 recently and used a Digitrax Dh465 Decoder for both Motors.It works Great.But it running it while pulling 50 cars or more i had problems with the 2 motors connected,it kept throwing a driveshaft.After dis-connecting the driveshaft from the motors,it pulled just fine.That is interesting. Was it always the same driveshaft or would they take turns? I'm wondering if there was too much torque for some tiny defect in one of them. I cannot say I've ever thrown a driveshaft.

diburning
03-17-2012, 10:53 PM
Were the the universal u-joint driveshafts? If so, I think it may be because the front drive isn't pulling as much weight as the rear drive, so the front motor would be trying to spin faster than the rear one.

A decoder with BEMF may solve that problem, but it also may get confused when it's hooked up to 2 motors.

Howie1632
03-18-2012, 07:39 AM
They didn't have u-joints,and yes it threw the rear the first time and the front the second time.After that i looked at many articles about remotoring these DD-40's and found one that said the 2 motors should be disconnected or there would be problems with drive-shafts.

Littlefoot14
03-18-2012, 08:28 AM
Athearn originally produced the dual motor DD40s with connected motors, and then later on opted not to connect them, finding they performed better without the motors being connect.

Dont forget about the new run of DD40AXs that Athearn is producing, theres a reason they didnt connect the two engines in the new DD40AXs, and its not just for cosmetic reasons.

Illinbah
04-08-2012, 07:33 PM
Not true.
You just aren't looking at stuff that is old enough.

My DD40 has the factory original motors joined - they are also corroded beyond repair.:(

take care ,,, ken

I have just acquired an old Bluebox DD40 with linked motors that is in very good condition but it pulls over 1.5Amp running and 3.5A stalled so I would like to re-motor it as I wish to fit a decoder for DCC running. I have never ventured into re-motoring before so am after a bit of advice as to which parts are required. Ahearns site advertise several motors, mounts etc but no descriptions as to what fits what. Could some knowledgeable member advise me as to which is the correct motor and what other parts I will require to do the task.

Thanks........Paul

diburning
04-09-2012, 02:15 AM
Your best bet is to clean and lubricate both motors to see if they still draw that much. If they are the older gray motors, or have any motors other than the gold sided ones, you'll have to remotor.

You can probably get two blue box junkers cheap, and take the motors out of those. Make sure to clean and lubricate them so that they don't draw too much power. You can then transplant them into your DD40 and wire for DCC.

If you're going to do DCC, you can get the plastic screw-on motor mounts either from Athearn or Digitrax (they're the same)

Illinbah
04-10-2012, 12:43 AM
When I bought the DD40 I did all the lube and cleaning etc. They are the old grey motors so I would like to replace with new gold flywheel types but Ahearn have several different part nos. So which one to use. I have looked at the motor in a bluebox AC4400 with gold motors but am concerned that if using that type the flywheels would be touching as the motor spacing is 76mm in the DD40 and in the AC4400 the motor including flywheels is 81mm. Reducing the length of the flywheels may be an option. What I really need is more detailed specification of motors available from Ahearn.

thanks Paul

thaddeusthudpucker
04-10-2012, 01:19 AM
I would actually not use Athearn motors.

Can motors would run a bit more smoothly. See:
http://www.micromark.com/motor-drive-system,9872.html

Dont worry about that wierd looking clippy-doodle, use it but use some strong adhesive to glue it to the frame.

Illinbah
04-10-2012, 01:29 AM
Thanks Nathan that is the sort of information I am looking for.

Cheers
Paul Andrews

tandmsimmons
01-10-2013, 05:18 PM
My dd40 is an older metal side frame dual motor with connected drive lines. The motors have no fly wheels. The loco runs great on dc power. I installed a digitrax sdh164 but it got cooked somehow. Digitrax sent me a new decoder so I'm thinking about trying again. Has anyone wired one? What did you do if you have wired one? I'm not interested in opinions. Digitrax says it will work if I wire the motors in "parallel" I'm not sure what that means mechanically.
My first attempt I wired the decoder directly to both using two wires running off each of the decoder + & -. Lasted about four hours.

Thanks let me know if you have experience.

diburning
01-10-2013, 06:15 PM
Yikes.

1. The metal sideframes can short on things inside the loco, or even to the frame. Shorts can fry decoders.

2. If your motors don't have flywheels, then they are the really old motors (gray colored?) that draw way too much power. The decoder would fry just trying to run one of those motors, let alone two.

Iron Horseman
01-10-2013, 08:18 PM
The thing is, I don't know if you'll be able to lash up two Athearn RTR/Genesis/Kato motors though because I don't think anyone makes a shaft with the hex end on both ends (they all have a hex on one end, and a dogbone on the other) You'd have to splice together two driveshafts somehow to connect the two motors mechanically. remove the plastic and connect the drive shafts directly with plastic/rubber tubing. I have found that fuel line tubing is good.

TrinityJayOne
01-11-2013, 12:09 AM
Digitrax says it will work if I wire the motors in "parallel" I'm not sure what that means mechanically.
My first attempt I wired the decoder directly to both using two wires running off each of the decoder + & -.
What you had was a parallel circuit, that is each motor was connected to the decoder independent of eachother. The other type is "series", where components are wired one after the other, or in series, hence the name. This diagram shows both.

http://i43.tinypic.com/2wri8li.jpg