OK, the MRC booster is out of the equation. I am running Digitrax SEB and using the N Scale setting so I have 12 volts to the rail and system passes the quarter test all the way around with the replaced bus wire on the C line.
I am back to wanting to convert some old DC engines to DCC namely my 20 year old Proto 2000 BL 2's.
One that fried the last time but, lasted the longest is the one I want to convert again. First time around it lasted well over 40 hours then smoked the decoder and harness badly. It was on the old DCC system and it was passing the quarter test so no short happened even while it cooked.
I did find the commuter and brushes had a ton of junk build up on it. I cleaned the junk out and pulled the motor and did a stall test. I used a MRC 2500 and cold the motor pulled 1.36 amps, then I ran it and used my finger to add drag on the flywheel to get it warm. It pulled 1.26 amps.
In this amp range, is this motor a good candidate to convert to DCC? I will be using my last new DH 123 AT if I get the thumps up.
Cuda Ken
I hate Rust
Ken
I do not know the DH123 amp rating. If its 1 1/2 amp it cuts it kind of close. Maybe would be better a 2 amp decoder for safety sakes. Maybe you should look at a TCS decoder. The T1 is a 2 amp and goof proof waranty to boot.
Pete
I pray every day I break even, Cause I can really use the money!
I started with nothing and still have most of it left!
Digitrax DH123 is rated for 1.5 amps continuous and 2 amps peak.
TCS A series is rated 1.3amp continuous and 2 amp peak.
With the numbers, I'd go with the Digitrax. For the goof proof warranty, TCS wins (but I'd still feel safer with the Digitrax)
Martin Myers
Next batch of Decoders will be NCE. They will give you one of there decoders for $10.00 for each toasted decoder you send them that is not theres. I have around 7 so for $70.00 and $2.00 shipping I get 7 new decoders. If I deep fat frying of decoders is over I may stick with them. But, I will buy some TCS decoders as well.
Would this be a better test on engine amp uses? My C Line can easily be converted back to DC. Take a DC engine I want to convert run it with say 20 cars and see what amps it uses with out being stalled? While I was trying to figure out what the problem was with my decoder eating bench. I ran a Athearn SD-50 at K-10 Model Trains. My stall test was 1.46 amps, on K-10 bench dragging 25 cars amps being used was only .50 amps.
Enjoying some Mozart Ken
The BEST way to test current draw is with a DC power pack that has both amp and volt meters. Run the loco with test leads or some other way to get it power with the shell off but not runnign down the track, and actually STOP the motor witht he flywheels - not just add drag. Make sure the volts don;t sag below 12 (you'll have to start out higher than 12) and read the amps. Don;t hold it long, just quick and take a reading. This is the maximum possible current the loco can draw, under the worst case conditions. It really should never get there except on quick starts from a standing stop, and then only for a fraction of a second. Unles sit has traction tires - then it can stall with too heavy a train on too steep a grade, and draw the stall current. But I hate traction tires, the loco should be able to spin its wheels if you tie a rope around the coupler and chain it to the bench. Armed now with the stall current, if the loco will spin rather than stall, you are safe with a decoder that can handle the stall load as a peak, the slip current as a continuous load. The only way that will blow a decoder is if the gears come apart and it actually does jam the motor. You can also check the numbers in MR product reviews if they've reviewed the model you have, at least to knwo if you're in the ballpak - if they got a 1.2 amp stall current and you get 3 amps - either your loco is defective or you're not reading it right. Or you have one of those early P2K's with the bad motor. Those 3-4 amp motors have to be repalced, there aren;t any HO decoders for that kind of current, plus with one loco drawing tha tmuch, it doesn't leave much for your other trains.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Based on what I've seen with the old P2K BL2s, the key here is motor isolation. The BL2s are a little tricky due to some close clearances beneath the motor and motor mounts that allow the motor to move end-to-end relative to the frame.
I blew up two decoders in old P2K BL2s before I noticed that there was enough play in the motor mounts that the bottom motor contact strip could come into contact with the metal frame when it was under load.
The solution was to glue a strip of plastic in the bottom of the slot in the bottom of the frame beneath the motor and, importantly, up the ends of the slot. I also reinforced the motor mounts by applying a little silicone bathtub caulk around their flanges before snapping them back into the frame.
Since then, I've had no problems at all with my BL2s.
-Fritz Milhaupt, Publications Editor, Pere Marquette Historical Society, Inc.http://www.pmhistsoc.org
In my opinion that loco draws to much current to convert to DCC. It's too close to the 1.3 amp rating of many HO decoders.