Postwar Lionel 250 Watt Type Z Used Transformer Saftey Check

[rack776]

Hi, I just bought a Type Z 250 Watt Transformer for a good price

Before I try to run some trains with it I thought I'd ask if someone give me a a safe way to check if the internal circuit breaker is working correctly.

I found the  face plate is from a Type V with a Z decal over top. The secondary coil, hold down bracket & short knob shafts looks like the correct parts for a  Z.    Is there a way to be certain it is a 250 watt Z coil by its size measurements?

The controls move smoothly and all knobs have the correct voltage range.

While I was checking out the insides I noticed the original circuit breaker light resistor is missing ( Lionel part number Q-8 ) and someone added modern yellow resistor wire instead.   I dont have the numbers printed on it with me right now. Is it possible to get a replacement lionel Q-8 resistor or what would be a suitable moden replacement for it.  What exactly is its purpose?

I Also noticed just the ends of the 4 enameled copper wires from the coil wiring have some areas where the brown coating has flaked off, they are not touching anything inside and I plan on insulating them, is this a normal sign of old age or is it a sign of the coil winding insulation is going bad? Nothing looks burnt or discolored. Copper is bright & shiny.

The rest of the coil looks OK other than some slight surface rust on the edges of the lamination plates. Someone has installed a new power cord. All Solder Joints look OK.

Any other tips on checking this transformer out would be appreciated.

-Jason Rackawack

 

[cwburfle]

IMHO, before any newly acquired old electrical device is plugged in, a visual inspection is in order. Sounds like you have that covered.

In addition to what you checked:

Carbon rollers - should be round, and turn as the contact arm sweeps across the coils.

- AC leakage - you can use one of those screwdrivers with a neon bulb in the handle to determine the presence of house level AC. Get comfortable using it. Then test the transfomer by touching different terminals, both common and hot. Also test various metal parts of the transformer.
Turn the plug over and repeat. The neon bulb should never light.

- output voltage - should be between 6.5 and 24 volts across any common post, and any "power" post, as the control knob is turned.

- CIrcuit breaker - If you short out a pair of terminals, such as common with "A", and set the voltage to the max, the breaker should open in less than 17 seconds. Be careful, what ever you use to short the terminals is very likely to get very hot, and may spark. Light wire could even melt. The test specificions for a "Z" say it will be putting out about 30 (thirty) amps across a .1 ohm load.

It should be noted that most Lionel transformers, including both the "V" and "Z" have very limited protection provided by the internal circuit breaker. The breaker is desgined to protect the transforrmer, not your wiring or your trains.  IMHO, 30 amps for 17 seconds can do some damage. Only circuits that pass through the "common" terminals are protected. If a circuit is created between any two "power" terminals ("A","B","C","D"), it is unprotected. For this reason, I always suggest that people use some sort of external protection on each of the "power" terminals.
I prefer postwar Lionel #91 adjustable electromagnetic circuit breakers. There are a number of other solutions.

[stubbsO]

To add to the above. I have 2 Z's, there a great transformer! Both of mine put out 25 volts each, but 24 works too. I would say that if it take 17 seconds for the breaker to pop is 10 seconds to long. I have never heard of or seen a breaker take that long to pop. Enjoy

[cwburfle]

stubbsO

To add to the above. I have 2 Z's, there a great transformer! Both of mine put out 25 volts each, but 24 works too. I would say that if it take 17 seconds for the breaker to pop is 10 seconds to long. I have never heard of or seen a breaker take that long to pop. Enjoy

My figures came from the factory service manual.
I guess the breakers should pop a bit quicker on a dead short.
I use a 5D test bench for the circuit breaker (and whistle control) test.
I never bothered to write down or remember how long the breakers took to pop on any of the transformers I've serviced. (all different models)  If they pass - good. If they fail, the breaker gets replaced. The breakers rarely fail.

[overlandflyer]

cwburfle

...

It should be noted that most Lionel transformers, including both the "V" and "Z" have very limited protection provided by the internal circuit breaker. The breaker is designed to protect the transformer, not your wiring or your trains.  IMHO, 30 amps for 17 seconds can do some damage. Only circuits that pass through the "common" terminals are protected. If a circuit is created between any two "power" terminals ("A","B","C","D"), it is unprotected. For this reason, I always suggest that people use some sort of external protection on each of the "power" terminals.
I prefer postwar Lionel #91 adjustable electromagnetic circuit breakers. There are a number of other solutions.

just thought it bore repeating.

cheers...gary

[rack776]

OK, I checked out the circuit breaker on this transformer and it trips in about 1 to 2 seconds,

I have 3 new questions about the wiring in a type Z I hope someone can answer these.

I found that there is no resistor on the warning lamp (man the bulb gets bright!) someone used regular automotive wire, I'm assuming the resistor is to lower the volts to the bulb - correct?

So my 1st question is -are the lionel Q-8 resistors still available or is there a way to calculate the load to buy a suitible modern replacement for it?

My 2nd question is this- Someone has soldered 2 short extension wires between the 2 ends of the smaller round magnet wire coil  and the circuit breaker screw head -  The 2 small round magnet wires are about 1/4" too short to reach the screw on the circuit breaker.  Is this OK this way or is the soldered joint a potential problem?

My 3rd question is - Are there supposed to be crimped on screw lugs on the 2 smaller magnet wire ends or are they supposed to wrap directly arround the screws on the circuit breaker?   The coil has one side with a Fat flat magnet wire going to the circuit breaker and the other side has two smaller round magnet wires going to the other side of it. 

Any help would be appreciated  - I'd love to put this back together properly.

-Jason Rackawack

[lionelsoni]

Here is a link to the service information:  http://pictures.olsenstoy.com/searchcd31.htm?itm=669

The lamps are supposed to be number 51 7.5-volt 220 milliampere bayonet-base G-3.5.  The resistor may have been to allow use of the same lamp in both sockets.  Or they may have thought that it regulated the lamp current, so that the short-circuit lamp's brightness varied less with the control setting, although the opposite is the case.  A 50-ohm resistor will put about the right voltage on the lamp with the control all the way up.  The resistor power rating should be about 5 watts.

However, you can put a higher-voltage lamp in there and leave the resistor out.  A number 53 would work.  It is rated for 14.4 volts and won't last as long at the maximum of 18 volts.  But most of the time the voltage won't be that high; and, since the main consequence of running it above its rated voltage is a shortened lifespan, that's not much of a problem for a lamp that will only be lit for a few seconds and infrequently at that.  (The 1445 is often mentioned when an 18-volt lamp is needed.  But it is just a 14-volt lamp with a dual rating, that runs hotter at 18 volts than the 53 and also burns out quickly.)

[rack776]

Thanks for the quick reply, the Olsens site is where I found the service manual & part numbers.....for pretty much everything I worked on so far, I plan on buying a Greenburg manual in a few weeks at the local train show.

 I found the Q-8 resistor is also used in the V, A & Q transformers with the same part number and I have an old type A for parts - I might just scavange the bulb resistor out of that. 

I realize the warning bulb is something you dont want to have lit at all, I'm not too worried about bulb life, I just want to make sure I'm not missing something.  I also thought it was to allow the same smaller watt  bulb after seeing how bright it gets when testing it .

I wonder if the previous owner discarded the resistor so he would not miss the warning light being on.

Anyone have an opinion on the short extension leads soldered onto the ends of the magnet wite - if its not a saftey problem having a joint as long as they are attached correctly & insulated I guess its ok to put it back together.    Any thoughts as to why it would be a problem?  

Also Are the coil leads just wraped arround the circuit breaker screws? I see no part number for a lug in the manual-

Anyone have a photo of an original Z with the bottom cover removed to see how the wires are supposed to be routed?

Thanks again for the help on this.

-Jason

[cwburfle]

Its been about six to nine months since I serviced a pair of "Z" transformers that I picked up at a local show. To the best of my memory, the following is correct:

Also Are the coil leads just wraped arround the circuit breaker screws? I see no part number for a lug in the manual 

 

[rack776]

Any thoughts on soldering extension wires between the core leads & the circuit breaker?

Am I better off unwinding 1 turn to get the extra length to reach the circuit breaker?

I think someone broke the very tip off of the coil leads and just tacked them to the breaker screw heads with solder

This is the only issue that has me concerned at this point - any advise would be appreciated

-Thanks Guys - Jason

[cwburfle]

IMHO, its impossible to comment without being able to inspect what was done.
If the proper sized wire was used to make the exension,  the soldering was done properly, and any necessary insulation was in place, I would be comfortable using the transformer.

I would not rermove a turn of wire.
IMHO, that is usually OK on a solenoid or a motor, but not on either the primary or secondary of a transfomer.

[lionelsoni]

I wouldn't either.  It's just too easy to make a completely safe, insulated splice.  Of course, you need to scrape off the insulating varnish at the end of the wire to expose the copper.

On the other hand, it's not unsafe to unwind a turn of a secondary winding.  The only effect will be to lower the voltage that the transformer puts out, which may not be a problem for the high-voltage Z.  You can estimate what that voltage reduction will be by counting the number of exposed rectangular wires on the face of the variable winding.  Divide 18 volts by that number.  It's probably less than 1 volt per turn.

[rack776]

Thanks for all the help everyone on this project I appreciate your time to respond-

I figured it was ok to splice on to the ends with the same size & type wire, The guy I got the transformer from said it was OK that way.  I just wanted a 2nd & 3rd opinion.

The only thing that made me second guess his repair work is the messy solder joints he made and lack of shrink tubing on the joints  even though they are not near other wires I'd feel better with clean solder joints and insulated conections,   I bought it from a guy with a good reputation for repairing transformers its all he sells and he is a TCA member. 

I personally feel a "reconditioned"  65 year old transformer should require more work than a repainted baseplate, repo faceplate decal & new power cord. 

I also think using 1/2 new phillips and 1/2 rusty original screws is cutting corners. I plan on finding the proper fastners for it.  Everything else inside looks servicable other than being very dusty, I checked the contact rollers are round and move smoothly....far from "fully restored"

I'm new to postwar lionel trains but I have restored full size automobiles for years, I guess its the same with every hobby,   You get what you pay for, Nice originals are always a better deal than "restored" items, and if you want it done right you have to do it your self.  Lesson learned.

-Jason