Phasing

[Anonymous]

I was looking at the post "Nuther Dumb Switch Question" and I read GGGMAN and MSACCO mention phasing two transformers. I have a transformer that I want to use for accessories and 022 switches. I am new to this and was wondering how to phase the two transformers and would something be ruined if they are not in phase?

John

[Anonymous]

Unlike DC which everyone knows is always Positive or negative the AC power we get from the wall and that runs our trains alternates from positive to negative and back 60 times a second. If you try to connect two transformers together you could have the output of one positive when the output of the other is negative. This results in a short and no worky. Phasing is the process of adjusting the transformers so that the outputs follow each other and is easy to accoumplish as follows.

Connect the common (usually the U terminal) terminal of both transformers together and leave the other terminals unconnected. Turn the output of both transformers up to about the same voltage. Connect a light bulb (train light about 14 to 24 volts) or a volt meter between the two outputs that have been left unconnected. The lamp should be dim or out and should increase in brightness as the voltage of either transmormer is decreased. If this is the case the transformers are in phase and no thurther adjustment is needed. If the light lights very brightely the the phase of one of the transformers needs to be changed. Do this by reversing the plug for one on the transformers in the wall outlet and retest.

[ChiefEagles]

If accessories are NOT attached to the track being run from other transformer, you do NOT have to phase. I phase ALL of my transformers just for the [oh well] of it. Several ways. Easiest to me is to run jumper wire from U [common] post from one transformer to the other, Power up both transformers to about half power. Take another jumper from the variable post on one transformer and touch the like post on the otter transformer. If it archs at lot [almost like welding], unplug one transformer and reverse the plug in the socket, repeat the process. Should not are very slightly arch. Paint the tops of both plugs so you will know how the plug them in. I do more. As NOT recomended by some written materials, I use polarized plugs. I wire all of my transformers in side the case to the same blade on the plug. A little extra work sometimes.

BTW: using different outlets tah tare on differnet circuits can cause phasing problems if they are on differenet "legs" within the breaker box.

[marmelmm]

Durned good question. I'm assuming that means ensuring that the plugs going to house current are both plugged in with the same polarity. How this can be verified short of hooking the transformers to an ocilloscope, present deponent knoweth not. If you want to be absolutely certain, use two identical transformers and retrofit them with matching polarized plugs.

In any event, if you keep the two transformers electrically isolated (i.e. use the plugs to disconnect the 022 switches from the track power supply), polarity won't be as much of an issue.

Feeding two sources of out of phase AC can damage electrical items, as they're getting pulses at a point in their operating cycle where they're not supposed to (similar to a car knocking or pinging when the ignition timing is off). However, your loco motors aren't going to vanish in a puff of smoke if said feed is of a short duration (although electronics can be damaged by this).

HTH!

VTY,

-MMM-

[MartyE]

See if this helps a bit...

http://www.martye.com/TipsandTricks/TipsandTrick2.htm

[lionelsoni]

"Transformers that will be used to power accessories that will share the common of the layout will also need to be phase for proper operation. These would include switches and isolated rail track sections for triggering accessories."

This statement from the "TipsandTricks" web site is not true. There is no reason why two circuits that use a common return must be powered by the same phase of AC voltage.

Those who use the fundamentally unsafe practice of running trains across gaps from one transformer output to another do need to have their transformer outputs in phase. The also need to have them set to exactly the same voltage. Those who customarily switch their blocks to keep the train powered by the same transformer should keep their track-power transformers in phase, just to reduce the risk of fire or damage when they accidentally cross the wrong gap.

In any case, traditional Lionel transformers should be supplemented with individual overcurrent protection on the outputs, which Lionel did not provide.

To add to Frank's advice concerning the 120-volt phases, there is a common wiring arrangement, called a "three-wire circuit" that puts opposite phases on the two halves of a single duplex recepticle.

[ChiefEagles]

QUOTE: Originally posted by lionelsoni
[br
To add to Frank's advice concerning the 120-volt phases, there is a common wiring arrangement, called a "three-wire circuit" that puts opposite phases on the two halves of a single duplex recepticle.

Bob, speak English. [;)] I use Bob as my chief electrical teacher. [:)]

[Anonymous]

My guess is --the indication of "FIRE" is running along with the replys to q's on PHASING> !st get in a licensed electrician who knows -best is your local wiring inspector. Better safe than Sorry ! tca oo51238 enjoy

[lionelsoni]

Okay, Frank.

A duplex recepticle is the kind of electrical outlet that just about everybody has, with two places to plug stuff in. If you were to take one out of the wall, you would probably see that there are separate screw terminals for the top half and the bottom half. On each side of the device, these are connected together by a metal link. The metal link can be removed by bending it back and forth a few times, so that the two halves can be disconnected. Then they can be wired to separate 120-volt circuits. If these circuits are out of phase with each other, they are allowed to use a single grounded conductor to complete the circuits, instead of having to have separate ones, since the return currents in the grounded conductor cancel each other rather than adding together. One wire is cheaper than two.

[lionelsoni]

A good way to avoid problems with the 120-volt-outlet phasing is to plug all the train stuff into a single "power strip" gadget, then plug its one plug into one wall outlet.

[Anonymous]

The transformers pluged into the power strip would still have to be in phase correct?

[waltrapp]

joncoy: I don't know if you asked your question rhetorically or not, but it's a good one for the unsure hobbyist. The answer is a resounding "yes". It's possible to have out-of-phase conditions between 2 transformers even when one is using a common powerstrip for both.

Bob knows that, obviously. I think he was saying that the 'safest' thing to do it is to use the power strip.

- walt

[Sturgeon-Phish]

With all this talk of phasing I thought I'd share a tip. Once I phase a transformer, I put a small dot on the hot side. This way when I plug in to a powerstip I just align the dots.
Jim

[trigtrax]

If accessories are NOT attached to the track being run from other transformer, you do NOT have to phase.

Altough it is true under the above conditions you don't have to phase. Phasing your transformers is good practice.. Layouts are always growing, most everybody adds new stuff. With unphased transformers you have the possibility of two chassis ( the metal parts of some accessories may also serve as a local ground) on your layout with 40 volts of AC potential difference between them. Under the right conditions this could be a fire hazard. So if your using multiple transformers always phase them anyway. Always keep your chassis grounds to the common connector and you'll avoid trouble.

[cnw1995]

Bob helped me learn more about this - especially with the older Lionel transformers whose plugs can go into the electrical outlet 'either way' - phasing sure is important if you are running more than one of these older ones.

[ChiefEagles]

Thanks Bob. Thought that was what you were saying. All the outlets I have added to the train room for transformers are from the same breaker so they are on the same leg in the breaker box.

[lionelsoni]

The reason I mentioned the power strip was that, if you do want your transformer outputs in phase, you could be tripped up if you moved one plug or another to another outlet, even on the same recepticle. The power strip's outlets are sure to be all at the same phase; so you can plug its one cord wherever you like without destroying the phase relationships among your transformers.

Jim's practice of putting a mark on the "hot" side of the plug will work of course as long as he is consistent. However, I would recommend marking the grounded-conductor side instead, since it is that side that is always required to be "identified" in the electric code, when identification is required.

I have replaced the plugs on the two type-Z transformers that I now use for my main layout with grounding plugs. I have wired them so that the transformer outputs are in phase with the primary and have grounded the common (U) terminal to the equipment ground inside the transformer.

[ChiefEagles]

QUOTE: Originally posted by lionelsoni

However, I would recommend marking the grounded-conductor side instead, since it is that side that is always required to be "identified" in the electric code, when identification is required.

I have replaced the plugs on the two type-Z transformers that I now use for my main layout with grounding plugs. I have wired them so that the transformer outputs are in phase with the primary and have grounded the common (U) terminal to the equipment ground inside the transformer.

What I've done too. Thanks Bob for your help.

[Anonymous]

The power I want to use for my accessories and the 022 switches will be coming from the accessory terminals (constant voltage) of a transformer not being used to run trains. I want to use two CW80's to run two trains. If the CW80's both have the plug with one wide blade do I still have to check them to see if they are in phase? If they are not would I have to grind down one blade to reverse it in the outlet? I am a bit confused.

[lionelsoni]

I would check them. I wouldn't trust a company that can't keep the whistle and bell straight.

You could grind it down, or cut it off and replace it with another plug, to get the transformers in phase. But the fact that one blade is wide suggests that there is something about the design that makes it safer to have a particular side of the input line grounded. A proper fix might involve swapping primary or secondary connections inside the box.