Enough Juice?

[stuartmit]

2 questions re power: 1. Got a 773 (1950) about 6 months ago, and have been running it alone on a loop powered by an RW, but it seems like not enough wattage, as compared with running on a loop with ZW power. Does that seem right? No hills to climb on the RW loop, a hill on the ZW loop. Maybe this loco just likes a challenge! 2. Have a Ross Custom double cross over installed in a yard, so typical operating speeds are low. Locomotives seem to conk out when the rollers are on either side of the "power diamond" in the exact center probably because the rollers are a little too close together.. I think I need to run faster so the e unit doesn't cycle, but in a yard, slow speed is what I need to use. I have this powered with only a 1033 and my single motor 624 switcher is unhappy. Maybe I should swap in an RW for more voltage to move through the area somewhat faster. Problem identical on 2343 which demands more power, so probably makes problem worse--can't run fast enough to make it across the diamond. Any thoughts?

[BigAl 956]

A lot to sort through. The RW should be able to power a 773. Is there any additional load on the RW?

Have you checked to be sure all these transformers are in phase? If you are running multiple transformers connected commonly on a layout phasing is critical else they will  be fighting against each other.

As for the crossover, the rails of Ross crossovers are not electrically tied together. If you have power on one side of the crossover you need to jump it to the other side or you will have a large dead spot.. Take the cover off a locomotive and run it over a crossover. When it stalls touch center and outside rail power and see if you can jump it to run. If that's what it takes you have a dead rail.

Finally, make sure all these locomotive are cleaned and lubed and have good brushes. Who knows, the last time your 773 was serviced may have been during the Truman administration..

[stuartmit]

I know about phasing and that is not a problem; I will try yr suggestion re cover removal. 773 is pulling 3 Madison cars by Lionel, and 2 early Williams knockoffs. Thanks for suggestions. Tomorrow v cold in in Northeast--good day to stay inside and work this out!

[lionelsoni]

The 773 tends to want more voltage than other postwar locomotives.  The RW puts out a maximum of 19 volts when A is used as the common.  The KW, ZW, and Z are better, with the Z reaching 25 volts.

Whether the transformers are in phase with each other makes no difference until you try to run between blocks powered by different transformers (but you shouldn't do that deliberately).  Actually, to the extent that out-of-phase transformers share a common return, they help each other to reduce voltage drop in that return, since the out-of-phase currents cancel each other.

[stuartmit]

Bob--you specify the RW output when A is used as common; I believe that would also be the same if U is used as common,and [aired with the A terminal, right?

[lionelsoni]

That's right.

However, the single-control postwar transformers like the RW are meant to have U connected to the center rail, since the whistle control and reversing switch are in series with that terminal.  I believe that they are also consistent in the whistle polarity (positive to the center rail) when connected this way.  That is unimportant for an older locomotive with a whistle relay, but makes a difference between whistle and bell with modern locomotives.  Wiring U to the center rail also makes the fixed accessory voltages more generally useful.

[stuartmit]

2 questions: So if you have Zw's connect with RW's, which I realize you are not a fan of, but does seem to work OK 99pct of the time ( I do know your concern about a circuit with no overload protection may develop in some circumstance), how does one do that-Term a,b,c,d from ZW to center rail, and term U from RW to center rail? question 2 why does it matter which of the two terminals the whistle circuitry and reversing switch are in series with, and isn't in Series mean connect in such a way as to always be the only path between two points in a system? Thus how could it matter which contact they are in series with--the two units are electrically between a and U with no path around them in any case.

[lionelsoni]

Connecting multiple transformers to a common return like the outside rails of the layout is fine with me.  What I advise against is running between blocks powered from different transformers and especially those powered by different outputs of the same transformer.  When different transformers are involved, there is overcurrent protection, since the currents pass through the circuit breakers of both transformers; but there is still a risk of generating voltage spikes harmful to train electronics.  There is no overcurrent protection between the multiple outputs of a transformer like the Z and ZW.

Yes, U is the best common for a ZW, and A (or B) is best for an RW.  If you're not using any of the fixed voltages from the RW for accessory circuits that need a common connection with the track voltage and your locomotives do not have modern polarity-sensitive whistle or bell features, it doesn't matter which of the RW's A and U you connect to which rail.  But, if you are counting on the RW for any of those items, A should go to the outside rails and U to the center rail.  Otherwise, the accessory voltage will vary in a not very useful way with the track voltage and especially when reversing or trying to blow the whistle, and the whistle control will operate the bell, if any.