So about 8 years ago I ripped the motor of a NWSL Little Joe out of the engine are replaced it with what I thought I was the right sized motor. A 20 mm x 32 mm 16000RPM motor. I put it in and it worked better than the motor that was in there originally, but it wasn't up to moving the engine much better than the original.
So my question is, should I put another motor of the same type in the engine or should I replace it with a pair of larger motors. I was thinking of a pair of NWSL motors 22 mm x 36mm 9600RPM. With appropriate connectors.
With the motors wired in parrellel, how do you put the decoder in?
To answer the question, the parallel leads of the motors are connected to the decoder motor leads. The decoder must be rated for the maximum current of both motors combined.
Your description doesn't make it clear what specific problem the dual motor install, or even the orginal motor replacement was supposed to solve. Nor is it clear whether or not there are mechanism issues which are causing the motors to be inadequate. The proposed install is going to be considerably slower than the existing, based on the RPM spec.
I usually suspect the mechanism as the culprit in performance issues until I have throughly checked it out. There are certainly some locomotives, particularly certain models of brass imports, that were built with inadequate motors. But I prefer to ensure the mechanism is free of binds and excess friction before attacking the motor.
my thoughts, your choices
Fred W
Hi Fred,
After I bought it started listening in on reports of problems with these engines. I picked up both the replacement parts of new 22 tooth axle gears and new screw shafts (I found out I had a bent one and just decided to replace both at the same time). The mechinizism turns light enough enough that I can lightly grip it and rotate it myself. I can't think of any other means of getting it smoother.
The other reason for two motors is that it seems to be straining, like it is too small for both screwshafts. The motor that was replaced was a fairly large open frame motor that tripped out my power packs the moment I set it on the tracks. Now at least the engine will move before the breaker trips.
I delubed everything, and then lightly coated the faceplates with lithium grease and the teeth with La Belle oil. There shouldn't be a bind at all. What's even more frustrating is that the single motor will pull the engine with one shaft removed (either of them) but at a very reduced speed, but trip immediately if both are put back in. This is the reason I though two motors would be better.
Sounds like a short. Is it possable that the motor itself is twisting in its mount causing a bind or a short?
Doug
Trynn_Allen2 So about 8 years ago I ripped the motor of a NWSL Little Joe out of the engine are replaced it with what I thought I was the right sized motor. A 20 mm x 32 mm 16000RPM motor. I put it in and it worked better than the motor that was in there originally, but it wasn't up to moving the engine much better than the original. So my question is, should I put another motor of the same type in the engine or should I replace it with a pair of larger motors. I was thinking of a pair of NWSL motors 22 mm x 36mm 9600RPM. With appropriate connectors.
I agree with David - hold off on the DCC conversion until you are sure everything is running well on DC. The best way to get a handle on what is really going on is to use an ammeter to measure actual current draw. Otherwise, we don't really have a good objective point of reference to know whether the mechanism is where it should be. If the mech is truly reasonable friction, you should be drawing less than 0.5 amps. More than that, and you are going to burn up motors (and decoders).
I have no clue as to what the original motor was, or what condition it was in. It bothers me that both the old and new motor are apparently tripping your DC circuit breaker. What is the power rating of the power pack or trip current of the circuit breaker? The 2032 at 16K RPM seems big enough at first blush, but the RPM appears pretty high for what should be a medium duty motor in a medium duty application. A single 2236 should be sufficient with a decent mech unless you are trying to pull (and have the loco weight to pull) 50+ cars.
A dual motor installation generally has issues because the 2 motors are never perfectly matched. At switching speeds the motors fight each other, increasing the achieveable minimum speed. At higher speeds, one motor or the other will be draw slightly more current and will carry a heavier load. The situation is really the same as trying to double-head locomotives. The capability of the two together will always be slightly less than the two separately.
DANSGRANDPAPA Sounds like a short. Is it possable that the motor itself is twisting in its mount causing a bind or a short? Doug
If it is a short, and it could be. It's not on the interior of the engine. The motor is mounted on doublesided racers tape, with a strap of single sided going over the top and the motor is mounted away from any of the interior stanchoens. If there is a short it is somewhere between the axles and lead coming up through the chasis. I found one short that was along the brake lines were it contacting the insulated side of the axles with the rail, and that was a bad one. A bit of solder and it isn't there. But it doesn't act like a short. I could understand a short on a corner Little Joes have more axles and more close work to the rails than any of my other locos, but with lights out on bad track work there are no sparks at all between the sideframes-axles, sideframes-chasis, or pilot truck/trailing truck to chasis.
Is it possible that the brass of the loco is chewing up amperage?
The DCC was me hoping for the future. My multimeter says that it draws about 6 amps before my Tech II 240 (the duel cab one) trips it's own breaker.
When I bought the engine the motor was bad. When I inspected the motor there were two blackened spots on the coils the length of the exposed windings that look an awful lot like the wheels got axles got jammed, which jammed the mechinism which stalled the motor and the motor started crispifiying. The guys at Midvale Hobby (here in Madison) said worked the jam out (pulled the bent screw shaft) and said replacing the motor would do it. I have since replace both of the screw shafts and drive axles with new ones, degreased and relubed so there shouldn't be a binding issue.
One other thing. last night we set it down on a DCC layout to run on address 0. All it did was short out the system. In DC it moves before it shorts the power pack. Short?
I would love to be able solve this issue myself, but i am wondering if this might be over my head and require a "professional".
It's either a short circuit or an overload. I suspect the short circuit from the additional information. What's the amp rating of the DCC system you were attempting to run on address 0? If it's more than 2 amps, you definitely have a short circuit. Less than that, it's possible for an overload, but even at 1.5 amps that motor is going to be sizzling hot within 30 seconds. So that would be your next check - how hot does the motor get before your DC power pack circuit breaker interrupted things? If it doesn't even get warm - short circuit in the locomotive is the culprit.
DC power pack circuit breakers are deliberately slow to interrupt things - so you can get around momentary short circuits. DCC systems have very fast acting circuit protection to prevent damage to DCC system and/or decoder.
Use your multimeter with the locomotive off the layout. Measure the resistance (ohms) between electrical pickup wheels of the opposite rails. Keep tracing the resistance back towards the motor until you find more than 0 ohms.
hope this helps