PWZW operating temperature

If a ZW is not being overloaded and the circuit breaker is operating properly the transformer should never be more than warm to the touch in the area of the emblem.

ZW's are not all powerful. A postwar dual motor diesel with 4 lit passenger cars (8 bulbs) and a freight headed by a post war Berkshire running simultaneously are about the most you should tax it if you are going to run for an extended time.

From what I have read on line, over 105 degrees F can feel more than warm. IMO a 122 degree sensor is too high to help.

I'm not sure sure that 122F inside the case is all that warm, there's a significant drop from the core temperature and the outside of the case.

Hi,

your concern about the Hi temperatures in the ZW is of concern, but not typically a  serious problem Linels great engineering feets, was not very good when it cameto thermal engineering. The ZW ccase has no vent holes in it. Adding a fan would not help much even if you could find a place to put it. A place for the cool air to enter, and the hot air to exhaust is needed.  Adding vent slots or holes to the ZW housing would go far in keeping it cool. Lionels record on cooling as I said was not a good one. 112 switches, tie ejection cars and passanger cars come to mind with melting plastic husings and other failures due to heat.

Paul

Years ago, one of our club members at Central Operating Lines (on Long Island) modified our ZW's and added computer fans where the large L on top was. A grille replaced the big L. I don't recall if any vents for air intake were added. This considerably cooled things down and was a huge improvement. The ZW's at the club were often in continuous use for 7-8 hours on Friday nights and for 12 hours during open houses.

I don't know if these transformers are still used. One had been replaced with a Z4000 just before I moved south. Perhaps LIRR Steamer could add some more info.

I seem to recall that a dentist that was a Lionel operator made rollers out of dental gold, which reduced the temperature markedly. However, at today's prices, this would make it cheaper to get a newer transformer! He did offer them for sale for a while, I regret not buying a couple sets when they were available.

I think that gold would pose a real problem for the rollers, since that would short adjacent turns with a very low resistance connection.  As previously mentioned in another thread, one reason for the carbon rollers is to offer a higher resistance when the roller bridges two windings as it must.

My own research has shown that running a typical postwar passenger train (A-A diesel set and 4 lighted cars) and a 736 Berk with 5-6 freight cars plus the assorted lights for switches and accessories will quickly warm up a foil-wrapped slice of pizza placed on top of the ZW.    

Wow if they could only figure out how to cool a beer it would be the PERFECT transformer!

Ron

Our club runs one of the layouts on a ZW, and our tinplate/postwar wizard rigged up a cooling fan for it. It does keep the temperature down. I don't know if we had any trouble with overheating before he installed the fan; he's out of town but I'll ask him when he gets back. 

Thanks for the input.  My parts came and I just opened the case to see what I'm up against.  After doing some initial test, I'm starting to wonder if heat would ever be a problem to worry about even if it's powered on for a week.  I have the trusty laser thermometer  out and waiting for it to even get warm. I don't feel any heat at all yet.  Paul, I'm starting to think like bigo and gunrunner, it it might not be a concern.  If so, I wasted $3 on a sensor.  It's not an original idea with the fan.  I saw that the new ZW has a fan so I was thinking why not.  I did plan on modifying the case for some air exchange.  A few neatly placed holes hear and there would allow the heat to escape.  Unless someone thinks that's a bad idea.  Train Doctor and Gunrunner, your gold comments are interesting  since the last I knew gold is the best conductor.  I just met a guy at a train show and he made the comments about replacing the carbon rollers with gold.  I thought it was intersting in concept.  But gunrunner mentioned something I haven't thought of yet.  Straddling the windings.  Would it really matter?  Because the voltage would be divided between the two regardless of carbon or gold wouldn't it???  Told you I was a newbie to trains.  I'll post my measured temperatures once it gets warm enough.

Tx all.  Dave

Without a load, the ZW will not heat up.  I have left them on for weeks at a time by accident, no heat.

The point about shorting adjacent windings together is simply that you are creating a shorted winding in the transformer!  This will result in excessive currents and probably arcing and erosion at the roller.  With the carbon rollers, any short is a higher resistance, and the carbon roller is so soft that it erodes and not the copper winding.  That's also why you have to periodically replace the carbon rollers.

IMO, a gold (or copper, brass, etc.) roller is a VERY bad idea.  There's a reason they used carbon rollers.

As far as venting the transformer, a few well placed 1/4" holes low on the case and a small fan at the top would work great I would imagine.  I'd probably use a 2" DC fan with a diode off a fixed voltage winding.

Dave,

From what I and others shared, I think your chasing a non problem. Certainly a fan or temperature sensing device is an over kill. If your concerned about the heat under heavy load conditions, the vent holes I suggested would be more than adequate. As far as the rollers are concerned, the carbon was used by Lionel because of the heat generated at the point of contrac, not in the core transformer. If any sparking occures the temperature at that point could reach thousands of degrees, but just at the point of contact. Gold or Cu is not the answer. The surface of either could pit and melt. Carbon is the right material from a wear and temperature standpoint!

Pul

ADCX Rob has it right: No load, no heat. The converse is also true: Too much load, too much heat. If you need to be applying an external source to cool down your ZW, you are pulling way too much current. Assuming 275watts, 18v, and 85% of peak, the max you should be pulling is ~12amps. Throw in a couple of postwar twin motor diesels, some lighted passenger cars, and all the lights on accessories, and you can easily exceed 12amps. Couple that with the fact that old ZW circuit breakers are notorious for failing to open at their rating, and you have an overloaded transformer. Far better to spend the $$ on a new breaker! Better yet, go buy a Z4000! You will never look back.

My two cents.

Chris

LVHR

PS We relegated our ZWs to accessory power, and use 3 Z4Ks to power the layout.

If the rollers are significantly worn, I recommend replacing them.  You can replace the rollers in the ZW without disassembly, so it's a pretty quick procedure.