Thanks Bob!
I just ordered some TVS units from Mouser Electronics. Hopefully that will keep my trains protected.
Lee F.
Regarding the TVS, I have seen it suggested that it be placed either across the track or across the lock-on so that it can intercept spikes from either direction. Is that the best placement? Could you also just solder four of them inside a PW ZW from A to U, etc?
Is a TVS useful for a layout with a modern transformer too?
Inside the ZW case is a very reasonable placement. Strictly speaking, the closer to the locomotive, the better, since that has the sensitive electronics that we are trying to protect. However, there is virtually no chance that any sort of harmful spike would be generated downstream form the transformer, since the wiring and track have very little inductance; and what distributed inductance they have is shunted by the distributed capacitance. So convenience wins hands-down here.
The only other placement option that I would give thought to is inside the locomotives themselves. This has the advantage that they would be protected when running as guests on another layout. Actually, there is no harm at all in putting them both in the locomotives and in the transformer box.
As for modern “transformers”, we run into the usual problem that we don’t know exactly what’s in there, apart from some educated guesses. But, again, there is no harm in using them just to be sure, since they are electrically invisible until the voltage gets too high, which shouldn’t happen in normal operation and which we want to prevent no matter how it happens.
Thanks, Bob. As always, very informative.
“Anyhow, I’ve found the the Polar runs up the tresles much better with the KW than the CW. That would be the KW on the 20v posts. Even ran well on full throttle on the 14v post. Don’t get me wrong, I really like my CW, but that KW runs the PE much better than the CW does.”
My goodness, I would think so! The KW was rated at 190 watts, while the CW-80 is rated at 80! Yes the VOLTAGE outputs are close, but the wattage is what you’ll need for those imposing grades.
Think: voltage=speed, but wattage=horse-power.
Even by the RMS methodology, the KW puts out more than a CW-80. Probably somewhere around 135 watts or so.
Jon [8D]
Well said, Jon (Kooljock1)
The KW was originally slated to put out 20 volts but this design was changed to 18 in the majority of those that were actually produced. The CW80 will probably not quite match the voltage output, even when lionelsoni’s celebrated voltage-conversion chart is applied; but the CW80 is not as powerful as a KW and I don’t know why anyone would think differently.
I see on that other forum that someone is complaining about the PowerMax. Evidently he was seduced into believing that it was rated at 80 watts. Somebody even posted a picture. Unfortunately, the photo was taken from the front, a view in which the CW80, the older BW80, and PowerMax all appear virtually identical. A better shot would have been from the rear where the CW80 and the PowerMax would look very different. At least one member has claimed that “PowerMax” is the name of both the CW80 (I’ve seen no evidence for that) and its 30-or-so watt baby brother. I posted very early on that the PowerMax was actually a powerpuff, and was greatly villified for doing so.
Because the PowerMax only comes with a certain few starter sets, and is not sold as a stand-alone item, most people have never seen one. When a person says it is so low-powered as to be “worthless” and then up pops a picture that most folks would see as the well-known CW80, he does a great disservice to the (now) well-performing CW80’s, in my opinion
Don’t forget the older Z’s and V’s were rated at 24 volts instead of the 20 of the ZW’s. You can send a couple of twin motor F-3 growlers with a boatload of cars rocketing around your track. I remember doing so long ago and noticing the tiny twenty-something gage wire in a 151 semafore melting in dispare…soo had to remove the signal and kept on a going…
I am interested in the that trick to limit the spikes as I think I fried an MTH proto I engine with the Z…
FWIW, I have compared postwar (Lionel 1033 @ 90 watt) and MPC-era transformers (Lionel 50 watt) to modern transformers of similar wattages (MTH Z-1000 @ 100 watts; MTH Z-500 @ 50 watts; Lionel set transformer @ 40 watts), and the older transformers - even those with lower wattage ratings - ALWAYS run conventional engines more smoothly. Ditto for motorized accessories. Those pure sine waves really do make a difference.
- Clint
P.S. My comparisons were done on the same layout with the same trains at the same time. The only thing that was changed was the transformers.
As it applies to rated voltage, at the time the Lionel pw ZW and other pw transformers were introduced, the household line voltage in the USA was typically 110 volts. Gradually line voltage was increased to 120vac and the output of the pw transformers reflected the increase----thus an 18 Vac rating, for example, increased to nearly 20 volts. If you experience a “brownout” situation as has occurred in some regions, your household line voltage may indeed drop back to 110 Vac or, less.
Maybe this is why I like Z’s over zw’s, even with the #??? controller hooked up to it. But everyone of these controllers that I have seems to get extremelly hot so I don’t use them. In a test with both the z and zw, the z will give me about another 30-50mph for anything that I run, plus it’s a more compact design than a zw.
The PW (prewar) transformers did expect 110 volts, certainly at the time the 1929 Lionel catalog was published. The PW (postwar transformers, however, were already up to 115 volts, according to the 1946 catalog. My copy of the 1953 NEC also assumes 115 volts.
I run my trains through a big 120-volt isolation transformer, using a 104-volt tap for prewar and 110 volts for postwar. My T and Zs stay gratifyingly cool.
Interesting set up Bob but I think you have to admit your arrangement is not typical nor available to the average o-gauger. He/she has to plug-in to the line voltage that exists and as you know on a nationwide basis voltage levels were seldom what the NEC assumed.
Right. I’m just saying that the likely average increase since the Z was made is more like 5 volts than 10.
It is possible to rewire a small train transformer for use as an autotransformer to reduce the line voltage to a much larger train transformer; but I’m not about to advise anyone how to do it who doesn’t already know what I’m talking about.
I’m sening this to the top because I found some fascinating and very useful things in here. I’m looking at a KW transformer for my under-the-tree layout and for use when upgrading my DCS system. I nearly got a hernia hauling out the Z-4000 to do an update. [(-D]
Note the excellent info about circuit breakers and fuses not being very useful for protecting locomotive electronics in newer locomotives. Good stuff!! Thank you Lionelsoni!! [tup]
Dep
You’re welcome, Dep!
Because of the great info in this thread it needs to be brought back to the top again around thanksgiving as thats when a lot start setting up there trains for the season and this has a lot of great info as dep mentioned. Bob is a big help electrically and man I could of used him tonight but it turned out to be more of a dumb mistake than electrical lol
You’re right. Let’s make a pact that either you or I will bring it back around that time. I just ordered a KW transformer from Davis Lyons at Lioneltransformer.com (http://www.lioneltransformer.com/) and Bob’s instructions are definitely going to be used in hooking her up. [:)]
