Litchfield Station has recently posted a "how to" link for re-motoring and decoder installation for older Life Like PAs. He says the old motors have a current stall of 3-4 amps, so goes on to re-motor before decoder installation.
Two questions:
1. How likely is this high current stall rating likely to be a problem in normal operation of a PA with 4 to 6 streamlined cars if a decoder with sound is installed but the loco is not remotored?
2. Would the same high amp motors be in other LL engines of the same age, and under what circumstances would it be an issue with an older E8 or GP7, for example?
Simply put, a motor with that high of a stall current could damage an HO or N scale DCC decoder if put under enough load. I've never heard of one in HO with that high current. Maybe O scale or higher?
Springfield PA
Can you say 'fast blow'? The highest rated HO decoder I've seen is 2 amps and that's peak. One half strained start and bye-bye decoder. Not all Life-Like locos of that time had such high stall amp ratings just as many other type locos didn't. My two 1970's era Atlas GP40's still have the original motors in them and they run just fine on Z Scale decoders.
Dr. Frankendiesel aka Scott Running BearSpace Mouse for president!15 year veteran fire fighterCollector of Apple //e'sRunning Bear EnterprisesHistory Channel Club life member.beatus homo qui invenit sapientiam
How lucky to ya feel...huh?
That amperage draw would be lethal within a second or two for the decoder trying to pass it through to your motor. Most decoders have an upper limit of 2 amps...or so the specs tell the buyer for warranty purposes. They may last days passing through 2.75 amps, but I would not have the stomach to test them for the sake of curiosity. 3.5-4 amps is asking to much.
But that is stall current. What will those motors draw pulling your 4-8 cars around curves of (what radius did you say they were), and you would need more amperage on any grades...so, really, we need a measurement under the conditions to which you will subject the motor(s). You would need a Ramp meter. You would want to know if it will always run close to 2.5 - 3 amps.
-Crandell
You WILL see the stall current or near it on a sudden start, or if you change direction without stopping first. So, like Dirty Harry said, do you feel lucky?
Test your loco - it's only the early run that had these bad motors. Before Walthers took over, Life Like used to have a production history on their web site so you could check your model and see when it was produced. They've been making P2K locos for a long time now, to the point that one that's 10-12 years old is too new to be one of the problem ones. But hook it up to DC via a meter and test it to be sure.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I don't know about yours but mine was so fast out of the box that it would fly off the track if the throttle was advanced too far. There was no such thing as a creeping speed. I hardwired a decoder into it and set it on the slowest speed table. Now it can easily run at slow speeds.
jeffrey-wimberly I don't know about yours but mine was so fast out of the box that it would fly off the track if the throttle was advanced too far. There was no such thing as a creeping speed. I hardwired a decoder into it and set it on the slowest speed table. Now it can easily run at slow speeds.
That happens with pretty much any modern HO loco using an old HO rheostat power pack - the newer motors are so efficient they get no voltage drop across the rheostat so even crackign the throttle results in full speed. Transistor throttles work differently and don't have this issue. Rememebr when there were different models for HO and N, like the MRC 501 and 501N? Different rheostat resistences to handle the different motors.
rrinkerjeffrey-wimberly I don't know about yours but mine was so fast out of the box that it would fly off the track if the throttle was advanced too far. There was no such thing as a creeping speed. I hardwired a decoder into it and set it on the slowest speed table. Now it can easily run at slow speeds. That happens with pretty much any modern HO loco using an old HO rheostat power pack - the newer motors are so efficient they get no voltage drop across the rheostat so even crackign the throttle results in full speed. Transistor throttles work differently and don't have this issue. Rememebr when there were different models for HO and N, like the MRC 501 and 501N? Different rheostat resistences to handle the different motors. --Randy