Lionel Type V Transformer circuit breaker

[stuartmit]

Lengthened the isolated control running rail, and my scheme works well (enough--any longer would cause trouble running in opposite direction

[stuartmit]

Installed a V and tried out my scheme. Have to tune it up to get the right length of isolated third rail

 

crazy thing about the V-- it seems the knob controlling A terminal is top left but the terminal is all the way on the right! 

[ADCX Rob]

stuartmit

is the voltage differential merely the difference of the two voltages

Yes.

But forget damage to the trains, you will hear/see/smell that.

The real problem is damage to the transformer... the fault current I have measured is small, under 4-5 amps at a few volts difference, but quickly jumps to 20-30 amps at 6-7 volts difference in throttle settings.  The Type V and Type Z transformers are quite powerful and have been known to burn through the secondary windings due to these fault currents.

Here is a PE car that had the two trucks straddling two power districts:

[stuartmit]

I understand what you say and know it is true but have never had the sort of event where I was aware of it. Th short circuit is of a few seconds ( or less) duration, while one roller is in one block and the other roller is in another. So I need an explanation;  forget for A minute this question of bridging two different throttles set  at different voltages.

in a normal short circuit, the center rail and the running rails are in someway directly connected, perhaps by a piece of wire left carelessly around, or a derailment of a metal truck which bridges the rails. In that case a direct path to ground is provided and, as i Think I understand it, the beneficial effect of a load which provides impedance is lost because the current prefers the short circuit path which is a path with zero impedance, or at least significantly lower impedance. your voltage differential may typically be 12or 15  or 19 V in that case (or some other value). but we know The system heats up rapidly.

now return to the question of two different voltages in adjacent blocks which are connected by pairs of rollers on a locomotive or a passenger car or caboose.  generally the potential on one side would be perhaps 14 V and the potential on the other side might be 19 V. First off, is the voltage differential merely the difference of the two voltages which would be less than the voltage differential in the normal short-circuit described above? Or is it the sum of the voltages which might be the case if the two transformers are out of phase with one another. Second--Is The danger and harm delivered merely by the fact that there is no mechanism by which after a few seconds, the whole system will be shut down by a circuit breaker? It seems to me that the incremental harm caused by the momentary bridging of the two dissimilar potential's on either side of the block divide is merely some incremental overheating of the conductors involved in the lightbulbs or even the locomotive coils. How much damage is really done when the condition only lasts for a second or two?  The real harm would be if the unit came to a stop while rollers of the same unit Bridged the two different blocks of track .  Two different roller equipped units, be they locomotives or little cars or cabooses, pose no problem at all even  if  coupled to one another but each is completely on one side or the other of the block junction. Only if they straddle the block do you have a problem. Is that correct? A lesson to be learned here then is not to ever stop a train while any roller bearing cars or locomotive Bridge the block Junction. Is that correct? in those cases, the condition could exist for quite a while and it's possible enough heat might be generated to damage the trains or perhaps even start something smoldering somewhere. Is the high school physics kind of dimming out?

 

 

 

 

 

 

 

 

[ADCX Rob]

stuartmit

will energize a relay feeding the higher voltage from the V to the center rail Of the ascending track

Just be aware, that like the terminal posts on the SW not having any overload protection between A & B, the V does not have any overload protection between A & B either... or A-C, A-D, B-C, B-D, or C-D.

Any time these combinations set to different voltages are bridged by trains... rollers etc., there will be a fairly severe short circuit in the secondary winding between the throttle taps / roller positions.

[stuartmit]

Thanks.  
my plan is to use it for a few stretches of grade track in a traditionally wired layout. I will create a block of track ahead of the grades with an isolated third rail about 20" long which, when occupied, will energize a relay feeding the higher voltage from the V to the center rail Of the ascending track. The cars behind locomotive will keep the relay energized until the locomotive is pretty much up the grade. At some point,  the last car will be beyond the control block, but the locomotive will be at the top of the grade and the voltage will drop back to the normal track voltage value.  Of Course when the train is running in the reverse direction, the relay won't be activated until the locomotive, as the train's leading unit, enters the controlling block, and the units seeing the higher voltage will be trailing cars, for which the voltage has no consequence.

[ADCX Rob]

stuartmit

I just would like to be sure that it has the same sort of circuit breaker protection that more recent transformers have had.

I can confirm that the Type V has the same sort of circuit breaker protection that the SW has.

[stuartmit]

In searching for better performance from my 773, in another thread, Bob Nelson commented that he runs his unit on older transformers which put out 25 Vac. I have a V transformer so I did a trial with it, and indeed got better performance than I was getting from my Sw transformer. I just would like to be sure that it has the same sort of circuit breaker protection that more recent transformers have had. Can someone comment on that?

[gunrunnerjohn]

I stumbled across this old thread, but I figured I'd add a point anyway.  Testing the outputs with a 1 ohm resistor is not the way to actually get anywhere close to the maximum output.  The transformer only delivers full power when set to the full voltage rating, i.e. using all of the windings. 

Let's assume you can get 100 watts output from the transformer, that would be 5A at 20 volts.  However, that does NOT mean you can get 20A at 5 volts from the transformer!

Another point.  This transformer is similar in construction to the KW and ZW in that it uses rollers on the coils, and a single output is capable of delivering all the power if so desired, you don't have to balance the outputs.

 

[Jark K. Remol]

Like I said, it's not sitting in my lap. But the point remains the same.

 Got the Type Vs because they were cheaper dollar per watt than a ZW.

[lionelsoni]

You're thinking of the Z, not the V, which Lionel rated at 150 watts in and 110 watts out.  You can get the full rated power from any of the 4 outputs or from a combination as long as the total doesn't exceed 110 watts.  (The Z is rated at 250 watts in and 180 watts out.)

[Jark K. Remol]

I have a pair of Type V transformers. If memory serves (don't got'em in front of me at the moment) they put out 250W total each. But that doesn't mean 250 W out of each control, and would be divided between them. The way the transformer coil is split, the only way to get that full 250 W is to use only one control at a time.

 I use a Type V each on two separate track blocks, and use 2-3 smaller 50-80 W transformers to power everything else. I can run a 726 Berk and some lighted PRR Madison cars with no problems. 

[servoguy]

Bob,

Good point about the resistor power rating.  I would add one thing to it:  Make sure you put the resistor on something that can stand the heat.  It is going to get toasty warm.  Don't hold it in your hand or lay it on your layout. 

 I don't know if the resistor you recommended is a wire wound resistor or not, but wire wound resistors can have very low temperature coefficients.  With the TC in mind, it might be a good idea to make the current measurements on each output independently and add the results together. 

Bruce Baker

[lionelsoni]

Keep in mind that, if you use Bruce's resistor method for measuring the current, you will need a resistor that can handle the power that it will get, which is 32 watts for the 1/2-ohm resistor and 64 watts for the 1-ohm resistor.  You could use 4 of these 1-ohm 10-watt resistors in parallel as a 1/4-ohm 40-watt resistor:  http://www.radioshack.com/product/index.jsp?productId=2062290&filterName=Type&filterValue=Power+resistors  (They are sold in pairs.)  The limit of 8 amperes will then correspond to 2 volts across the resistor and 16 watts of dissipation.  It's a good idea in this situation to keep the actual power dissipation well below the resistor's rating, since its resistance will rise as it heats up, spoiling the accuracy of the measurement.

Another consideration is that the voltage across the resistor is not available to the train and other loads; so you'll have to turn up their voltage controls to restore the normal voltage to them.  The V (and the Z) have enough range that you can probably do that without bumping into the end of the dial.

[OhioZephyr]

Bruce,

Thanks for your insight too.  I'm kinda like you, I keep hearing this little voice in my head that says it is not big enough.  Again, thanks. 

 

[OhioZephyr]

THanks Bob,

I like both ideas, particularly the back up 10 amp breaker. 

 

[servoguy]

I have a Type V transformer, and have found it doesn't supply a lot of current.  I would advise against trying to adjust the internal breaker as I think you are overloading the transformer in the present situation.  I was trying to power quite a few 022 switches with the Type V and also run two trains with no accessories.  The circuit breaker kept tripping so I solved the problem by adding two KWs to the layout.  Even though the Type V has four controls, it won't really run four engines of any size. 

Probably the cheapest way to measure the current is to put a 1 ohm or 1/2 ohm resister in series with the U terminal and measure the voltage across the resister.  Then use Ohms law to calculate the current.  The current will be the voltage divided by the resistance.  If you measure more than 4 volts across the 1/2 ohm resistor, you are drawing too much current from the transformer.

The reason it runs for about 15 minutes is that the circuit breaker is a thermal breaker, and as the transformer heats up, it heats up the breaker also, and actually reduces the current capacity of the breaker.

Bruce Baker

[lionelsoni]

Lionel rated the V for "...about 8 amperes at the working track voltage."  You can check this if you have an AC ammeter by placing it in series with the common (U) terminals; but I think it likely that you are drawing that much current and that the circuit breaker is doing its job properly.

Another way to test it, that might be easier than finding an ammeter, is to buy a 10-ampere automotive circuit breaker, which is functionally a very close replacement for the original in your transformer.  Put the automotive breaker in series with the U terminals and temporarily jumper around the internal circuit breaker.  If this stops the tripping, then perhaps your internal breaker is faulty.  Then you can replace it with the automotive breaker.

[OhioZephyr]

I have the above transformer that I use to power a small standard gauge layout.  One control is used for lighting the layout, one conrol is used to activate turnouts and accessories, the third control is for the train.  I'm operating a 384 loco with three 500 series cars.  After I operate for say 15 mins the transformer cuts in and out dropping the power for everything.  If I turn off the train everything come back on.  Is it the breaker, can it be adjusted? Thanks for any help.