Overheated postwar transformer?

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October 22, 2011 9:59 AM

I've got a 1033 Lionel 90 watt transformer that I use for lights/accessories. Its been working great for several months. Last weekend, however, after running my trains for several hours I noticed that this transformer was overheating; So much so, in fact, that at one point I went to touch it and it was so hot that the red handle was starting to melt. I replaced the unit with a type V 150 watt transformer for the 1950's and that helped. But I let the type V run for several hours and, though it did not overheat, the lights began to flicker on occasion as if there was something going on over time.

Questions: 1.) Was I running too many watts off of this transformer -- the 1033? 2.) Are these transformers supposed to have shut off circuits when they overheat? If not can you install one? Are they all this dangerous? My obvious concern is, if I fell asleep in my train room or forgot to turn off the transformer, couldn't it cause a fire? I like the look and performance of these old classics, but I'm concerned about safety.

Mike
 
 
 
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October 22, 2011 10:15 AM

First, depends on how many lights you are running and the current they pull in total. See if you can borrow an amp meter and measure the current. Then multiply by the voltage being put out which give wattage (or technically volt-amps which you can multiply by 75% (rule of thumb) to get approximate watts). Ideally the computed power draw wattage should be about 75% or so of the tranformer maximum wattage.

Wonder if you have some kind of wiring error that maybe is accidently powering an accessory, or just perhaps (outside chance) somehow cross connected and "fighting" with another transformer. Or some frayed wiring that is allowing some current leakage. Feel all the wiring for hot spots when flickering and dimming starts, and repair where needed.

Hope this helps.
 

 

Thanks,

Sam

Free lancing the fictitious Iowa division of Pittsburgh & West Virginia RR

 
 
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October 22, 2011 10:19 AM

Not knowing how you have hooked up things you may have some wiring that in effect partially but not commpletly shorting out part of the transformers windings. Had this happen with my ZW where I some how cross connected the A nd C handles and when they were set to certain place the wiring began back feeding to each winding and the ZW smelled bakelite HOT but the breakers never tripped.
 

 

Thanks,

Sam

Free lancing the fictitious Iowa division of Pittsburgh & West Virginia RR

 
 
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October 22, 2011 10:39 AM

quote:
Had this happen with my ZW where I some how cross connected the A nd C handles and when they were set to certain place the wiring began back feeding to each winding and the ZW smelled bakelite HOT but the breakers never tripped.


In almost all postwar Lionel transformers, including the ZW, the circuit described above ("A" and "C" terminals) is not protected by the internal breaker. This is one of the reasons I always recommend putting a breaker on each terminal, "A", "B", "C", and "D".
There are many options, I use Lionel postwar #91 adjustable electromagnetic circuit breakers. They trip instantly. Be aware, that one can adjust them to the point where they won't work.
 
C.W. Burfle
 
 
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October 22, 2011 10:44 AM

Interesting, Sam. So are you saying if it was hooked up properly, the transformer should have tripped?
 
 
 
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October 22, 2011 12:03 PM

Well the outputs do not have individual breakers so its possible that you can cross connect windings. In my case it was an insulating pin that failed between track loops so A and C cross connected. See Mr Burfle's explanation above. UL says only that the transformer must fail safely without fire, so I guess overheating doesn't count unless it rises to an igition point.
 

 

Thanks,

Sam

Free lancing the fictitious Iowa division of Pittsburgh & West Virginia RR

 
 
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October 22, 2011 2:50 PM

Mike, I have the PW 1034 75 watt. It's I think the same as yours except no red handle and a little less power. I used to run it for all my lights and it did OK until the number of bulbs grew to 40 something. Then it got real hot quick and quit. I know some may say it has no breaker and honestly I don't know WHAT it has, but it did cut out on me with that many.

I took some readings, which I may still have if you're interested, and considered getting a PW ZW for lighting, but wound up going with a New ZW and two 180 bricks. Now I don't need to worry about the number of lights.

The 1034 I still use for lighting and I limit it to 15. It will handle those for an hour without any problem.

Btw, how many lights are you running? Second btw, I wouldn't put more than a few dollars into fixing it. There are now plenty of older good condition transformers on the market cheap.
 
 
 
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October 22, 2011 2:50 PM

Sounds like the circuit breaker in the 1033 wasn't tripping in spite of what appears to be excessive current draw. You can replace that pretty easily if it's failed.
 

TCA, North Penn O-Gaugers, MTH ASC Certified Technician

 

Nothing is so easy as the job you imagine someone else doing.

 
 
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October 23, 2011 12:06 PM

Related question, not meant to hijack thread:
If a PW transformer such as the 1033 has no wiring issues and is turned
off (0 volts output) BUT is left plugged into 110 wall current continuously for up to 24 hrs. on occasion, would this damage the transformer or be a safety hazard? Also, same question for a modern transformer?
Thanks, TomB
 
 
 
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October 23, 2011 1:27 PM

I'm embarrassed to admit this, but yes, I think I may have overlooked the number of lights. I counted them and they total 35. I think I read in one of the magazines that the average little bulb (I use Radio Shack #52) uses about 4 watts. That brings the total to 140 watts! Which, I guess also explains why my 150 watts Type V gets hot after a few hours -- because it's pushing the load limit -- as another forum member points out -- you should only use 75%.

I'm still confused, however, why these transformers don't shut off when they get too hot. Does it simply come down to old technology? If so, I'm going to invest in a modern transformer for lights because it is far more safe for my home.
 
 
 
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October 23, 2011 1:39 PM

quote:
Originally posted by boxcoupler:
Related question, not meant to hijack thread:
If a PW transformer such as the 1033 has no wiring issues and is turned
off (0 volts output) BUT is left plugged into 110 wall current continuously for up to 24 hrs. on occasion, would this damage the transformer or be a safety hazard? Also, same question for a modern transformer?
Thanks, TomB


No harm done but the tranformer primary is still drawing some current. There would be no safety issue if transformer is UL approved as one on the test is to confine a device without air circulation to see if it overheats or cause a fire or other unsafe condition(s). So if your UL approved transformer is sitting out with room air surrounding it, the transformer would hum away hour after hour running up gigantic electric bills Razz.
 

 

Thanks,

Sam

Free lancing the fictitious Iowa division of Pittsburgh & West Virginia RR

 
 
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October 23, 2011 1:44 PM

quote:
Originally posted by IRON HORSE:
I'm still confused, however, why these transformers don't shut off when they get too hot. Does it simply come down to old technology? If so, I'm going to invest in a modern transformer for lights because it is far more safe for my home.


Older transformers AFAIK did not have thermal fuse buried within the winding core to sense overheating. Unsure what Lionel, MTH etc have to do to meet UL approval with the big transformers.
Some of the (non-train) tranformers we sell as electronic distributor seem to have some kind of sensing. If overheated they open the path either permanantly or reset after awhile.
 

 

Thanks,

Sam

Free lancing the fictitious Iowa division of Pittsburgh & West Virginia RR

 
 
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October 23, 2011 2:34 PM

T he 1033 has a circuit breaker, but it's a somewhat failure-prone item. It sounds like this may not be working properly in your case.
 

TCA, North Penn O-Gaugers, MTH ASC Certified Technician

 

Nothing is so easy as the job you imagine someone else doing.

 
 
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October 23, 2011 9:56 PM

quote:
Originally posted by boxcoupler:
quote:
Originally posted by rrman:
quote:
Originally posted by boxcoupler:
Related question, not meant to hijack thread:
If a PW transformer such as the 1033 has no wiring issues and is turned
off (0 volts output) BUT is left plugged into 110 wall current continuously for up to 24 hrs. on occasion, would this damage the transformer or be a safety hazard? Also, same question for a modern transformer?
Thanks, TomB


No harm done but the tranformer primary is still drawing some current. There would be no safety issue if transformer is UL approved as one on the test is to confine a device without air circulation to see if it overheats or cause a fire or other unsafe condition(s). So if your UL approved transformer is sitting out with room air surrounding it, the transformer would hum away hour after hour running up gigantic electric bills Razz.



rrman - Thanks for the above response. As a follow-up question, about how many watts would a 90 watt transformer consume while humming away on the OFF position (no load). 90? 50? 5? ???
Thanks again, TomB
 
 
 
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October 24, 2011 9:35 AM

It so happens that I have a 1033 on my workbench for testing, so I stuck my clamp-on ammeter on the power input.

.3A @ 120 VAC = 36VA

That is roughly equal to 36 watts, however given the power factor correction, it's probably in the low 40's as far as watts consumed.

With a load of 6A on the transformer, it consumes.

.9A @ 120 VAC = 108VA

That is in the 120 watt range of actual power consumption. I don't have the direct means to measure power factor, so I can't give an exact figure.
 

TCA, North Penn O-Gaugers, MTH ASC Certified Technician

 

Nothing is so easy as the job you imagine someone else doing.

 
 
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October 24, 2011 3:05 PM

quote:
Originally posted by gunrunnerjohn:
It so happens that I have a 1033 on my workbench for testing, so I stuck my clamp-on ammeter on the power input.

.3A @ 120 VAC = 36VA



Thanks gun, that .3A measurement answers my question. I thought (hoped?) that the number might be lower. Smile
TomB
 
 
 
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October 24, 2011 6:08 PM

Those old transformers aren't all that efficient, even with no load, so I turn off the bench power when I'm not using it. Smile
 

TCA, North Penn O-Gaugers, MTH ASC Certified Technician

 

Nothing is so easy as the job you imagine someone else doing.

 
 
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October 24, 2011 6:29 PM

Ever since I received my first transformer, a KW, in 1951, I have thought it common practice to never ever leave a postwar transformer plugged in when not in use.

This caution was included in the Lionel postwar literature and every other reference I have ever seen.

When a ZW was left plugged in overnight at the museum where we were running the club layout, we returned next day to find the distinct aroma of warm insulation in the room, even though all handles were off. It's one of those "theoreticals", I guess. In theory it might be OK, but don't ever do it! Big Grin

There are always stories about someone leaving a train running and then going away on a weekend trip, finally coming home days later to find the train still running just fine. But, then again, there are some people who win the lottery too! Big Grin

Most modern transformers have an "on-off" switch which kills power entering the device.

I've always thought it a good practice to have a master power switch which kills power to the entire train room, lights and controls. Makes it harder to forget that way. Smile

Jim


Edited to change never to never ever !!!!!!
 
Last edited by Jim Policastro October 24, 2011 7:49 PM
 
 
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October 24, 2011 8:06 PM

quote:
Originally posted by IRON HORSE:
I'm embarrassed to admit this, but yes, I think I may have overlooked the number of lights. I counted them and they total 35. I think I read in one of the magazines that the average little bulb (I use Radio Shack #52) uses about 4 watts. That brings the total to 140 watts! Which, I guess also explains why my 150 watts Type V gets hot after a few hours -- because it's pushing the load limit -- as another forum member points out -- you should only use 75%.

I'm still confused, however, why these transformers don't shut off when they get too hot. Does it simply come down to old technology? If so, I'm going to invest in a modern transformer for lights because it is far more safe for my home.


Not only that, but if you read the postwar guides, they will all tell you that while the transformer is rated at 150W (V) or 250(Z) for example that you will only be able to extract 70-80% of that total as a continuous draw over extended time...like running your lights. If I remember correctly the 250W rating is good for about 180W continuous. (Opps Sam beat me to it!! but this is really the key to sizing your postwar transformer power needs and not coming up short!!!)

But, I use and have no issue using any of these postwar transformers on my layout...provided they are serviced correctly, which I do my own self. Rivet's, roller's, a correctly sized cord, and a proper inspection of internal wiring, solder joints and insulation is in order.

And yes, i am embarrassed to admit, that I have unintensionally left the ZW plugged in over night..and yes the case gets very warm just sitting there plugged in. That's enough right there to make you remember the next time.
 

Dennis Holler If its old and broke, I like it

 
 
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October 24, 2011 8:15 PM

An incident happened when I was around 8 in 1959. I was at the next door neighbors house playing with Kenny with his Lionel train. It was just an oval set up on carpet with the 30 watt transformer or whatever came with those type sets. We went outside to play and his mother when with us and sometime later - I would guess 30 or 45 minutes his father came home from work. When we all went back into the house there was a terrible burning smell. The transformer had gotten so hot it melted completely through the carpet to the wood underneath.

I know it was still plugged in and possibly, although I don't remember, the train could have fallen off the track and the power lever was left as it set when we left the track to go outside.
 
 
 
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October 25, 2011 7:25 PM

To all,

I just want to say "Thanks" to all of you for your responses to my post. Once again, I've discovered that, if you have an O Gauge question or issue, this forum is the most easy and insightful way to answer your questions. There are so many talented, intelligent and experienced train guys here. Anyone new to the hobby or (like me) are experienced and looking for some expert advice, I offer this:

Here lies the "Buddahs" of O gauge; if you are confused or frustrated, don't fret, ask the question and these these guys will lead you to enlightenment...

Mike
 
 
 
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