I have a PSX-AR Auto Reverser to power the reverse loop with the appropriate gaps and it is powered by a Digitrax DB150 Booster. On the mainline, with a RRampMeter and a taillight bulb clipped on as a load I get over 12 volts and 2 amps. When I test the loop I get no readings. But when I unclip the taillight bulb and just use the RRampMeter I get a reading of over 14 volts and 0 amps on the loop.
The loop is quite long, over 16 ft, and I have feeders every 5-6 ft powered by the PSX-AR. It is hooked up according to the instructions. The program jumper is on pins 2-3 of J3 and both red LEDs that are supposed to be on are on.
So I can’t figure out why the meter shows volts but no amps on the loop. When I do the quarter test and short the track I don’t get any beeps from the booster.
What happens when you put a locomotive on it, both running in the loop and making the transitions over the gaps back to the main line? What kind of turnout(s) are at the end(s) of the reversing section? Is the booster doing anything else other than running the reverse loop?
What happens when you put a locomotive on it, both running in the loop and making the transitions over the gaps back to the main line? What kind of turnout(s) are at the end(s) of the reversing section? Is the booster doing anything else other than running the reverse loop?
The loco will run across it and around the loop okay. The turnout is a handlaid FastTrack with a TamValley Frog Juicer powering the frog. The booster runs the second level but I haven’t finished laying track on what will be the other half.
Not really. As the taillight gets hot, resistance increases rapidly and the amperage drops. That’s why people used taillights to protext DCC blocks before ciurcuit breakers. Try what others have told you with a loco.
The PSX-AR works as both an autoreverser and circuit breaker. I suspect it sees the load of the light bulb as a short and is shutting off power to the reversing section. Try increasing the trip current of the PSX-AR.
Just curious as to why you are using the bulb as opposed to just placing an engine (running) on the track. An automotive tail light bulb will draw considerably more current than any of your engines.
According to the RRampMeter Application Notes “It is almost impossible to get a good stable voltage reading using a train running as a current load. The best way to measure the loss is with some type of steady load. An automotive lamp turns out to be a good device to use as a steady load.”
I don’t get any volt or amp reading on the loop. I don’t know if that’s good or bad.
Yes, because of the wheel to rail connection, load with a singla locomotive will fluctuate. But do we care? We want to know if we are getting sufficient power to run a train. You have voltage, so clearly thre is power. But depending on the tail light bulb you are using, the current could be over 2 amps and depending on the setting of the PSX it could be tripping it. Or even more likely, light bulbs have an inrush current when the filament is cold and as such it could be keeping the the PSX from even turning on.
Earlier, you said that you get 14 volts on the loop, but now you are saying that you get no volts on the loop.
How are you using your RRampMeter? If the RRampMeter is wired in-line, using the cables and alligator clips connected to the bus wires, you can read both volts and amps. But if you disconnect the RRampMeter from the cables and use it as a portable device by holding it against the rails, you can only get voltage readings, not amps.
He stated in his second post “The loco will run across it and around the loop okay.”
From his first post: he gets no readings with the lightbulb and 14 volts without it.
The thing about testing it with a locomotive is that’s likely not a good true test of the loop unless that is all you ever plan on running through it. To truly give it a good test you want something that draws whatever the worst case scenario is for what you’ll be running through the loop.
Well if the light bulb is tripping the PSX breaker, then no, there would be no voltage or current reading on the rrampmeter.
I still say it’s just the light bulb not allowing the PSX to close the circuit, it thinks there is a short or overload. Especially if a loco works fine.
Other test, lay a quarter on the rails, check the voltage to verify the PSX shuts down. I don;t see the obsession with verifying current. If a loco negotiates the loop with no problems, AND the power is cut off in the event of a real short (quarter test) without tripping the main booster, then all is fine.
To properly test current under load, you need a stable load, not a light bulb. Need something on the order of a 7 ohm, 30 watt resistor to draw 2 amps at 14 volts, and it WILL get quite warm, but it will put a 2 amp load on the circuit and 2 amp only. Or you could simply consist 3 or 4 locos together, if that will be your biggest consist, and try them. No need to make things more complicated trying to easure and calulate that which can be easily verified with empirical testing, in this case, it’s not as if it will damage the locos or the PSX if it doesn’t work. Guess that’s why I’m an engineer and not a scientist, or something.
I don’t have any PSX-AR units. I use AR-1’s as auto-reversers. Can you disable the circuit breaker function on the PSX-AR and still keep the auto-reverser function enabled?
If you can, why not just disable the circuit breaker function for testing purposes?
If a loco runs through the reversing section OK what is the problem? Don’t keep trying to fix what ain’t broke. The AR’s operate by detecting a short condition when a loco wheel passes the insulated joiners going into the reversing section. It (the AR) then reacts to the short and instantly changes the polarity to compensate, A light bulb it not a good thing to use to test the AR because it is not on both the approaching track section and the reversing section at the same time. If a loco passes through the reversing section in both directions OK then there’s nothing wrong.
I don’t think he is using the lightbulb to test the operation of the reverse loop, the main purpose of using the RRampMeter the way he is describing is to check for voltage drop to insure adequate wiring.
Which I think is successful because the PSX is cutting power due tot he light bulb drawing too much - actually I’ve seen enough posts about PSX’s and PSX-ARs that say the “weak system boost” option needs to be enabled to handle the inrush of some sound decoders even if the booster powerign it is 5 amp - the isntructions pretty much say that this option si only for the lower power starter systems liek powercab and Zephyr, but results seen here and on other forums suggest that it is needed for ALL systems.
To analyze voltage drop at a given current drop, you still need an adequate stable load, like a big sandbar resistor. Light bulbs are by nature variable loads.
Or, likes I said, just do a quarter test all along the reversing section. If setting a quarter on the rails at any point within the reversing section causes the PSX to drop out and not the main booster, all is good, the bus is sufficent and there are enough feeders to prevent excessive voltage drop. Coupled with a locomotive able to properly negotiate the loop and not stall or hesitate when entering or leaving the reversing section, and it’s definitely wired correctly.