KW electric cord

Nww to replace the power cords
       

What is that you posted?

I've replaced them without removing the coils, but it's an interesting exercise!  I hesitate to try to describe the method, and it involves some unusual tools.

I keep a few of those posts around, the originals are pretty fragile.  The good news is they're easy to install, and they'll never break again!

quote:

I wonder if Lionel or any manufacturers specified which cord wire went to which primary lug (Any transformer repair persons confirm the ribbed wire always went to one lug or other for given model?) 

 

I have serviced many transformers, and had many more pass through my hands. I don't recall ever seeing a Postwar Lionel transformer with either a polarized cord or plug. Maybe I just didn't notice?

In my experience as an electrician and transformer repairman:

The wiring convention for postwar ZW transformers is for the ribbed wire of the power cord to be attached the bottom of the ZW 120V contact plate.  Note that polarized plugs are made with the ribbed wire of the 2 wire cord attached to the wide blade.

Attach the neutral (ribbed) wire to the bottom of that contact plate and your postwar ZWs will be in phase with most modern transformers also.   Always double check. Factories are still making errors.

quote:

In my experience as an electrician and transformer repairman:

The wiring convention for postwar ZW transformers is for the ribbed wire of the power cord to be attached the bottom of the ZW 120V contact plate.  Note that polarized plugs are made with the ribbed wire of the 2 wire cord attached to the wide blade.

 

Where did the convention orignate? Have you seen a ZW transformer with an original Lionel polarized Lionel cord? I ask because as I posted above, I have not.

As I have commented here in the past, there should be an "O-Gauge Standard" that defines the standard polarity of the output of an O-gauge transformer as either non-inverting or inverting polarity for all products.  The most obvious choice would be non-inverting, but Jon at Lionel told me their standard was non-inverting.

 

A non-inverting polarity means that when the incoming line voltage is rising from a zero crossing in a positive direction, the output voltage will also be rising.  An inverting polarity means the input and output voltages are going in the opposite directions.

 

If there was such a standard, and if manufacturers adhered to it, we wouldn't have problems like the run of Lionel Powerhouses that had reversed outputs.

CW, my English is deficient.  You asked, "Where did the convention orignate? Have you seen a ZW transformer with an original Lionel polarized Lionel cord? I ask because as I posted above, I have not."

 

The convention I spoke of regarded the attachment of the core with with ribbed insulation to the bottom terminal in the ZW.  All the original cords I have seen had the ribbed cord connected to the bottom terminal.  No original cords had polarized plugs.

 

On modern 2 wire cords with polarized plugs the wire with ribbing on the insulation is attached to the wide/neutral blade of the plug.  If you buy a #16 2 wire cord with a polarized plug attached and connect the ribbed wire to the bottom ZW terminal, it will "probably be in phase with modern transformers" when plugged into a polarized plug strip.

quote:

The convention I spoke of regarded the attachment of the core with with ribbed insulation to the bottom terminal in the ZW.  All the original cords I have seen had the ribbed cord connected to the bottom terminal.  No original cords had polarized plugs.

 

How curious! Why would Lionel have their assemblers orient the cord when the plug was not polarized?

I have not had too much success on the web finding a difinitive answer on when ploarized outlets and plugs came into being. One site matched DPC's estimate of the 1970's. Multiple sites put the date much earlier, into the 1950's.
Here is a quote from a site with an even earlier date:

quote:

Polarized plugs (one blade wider than the other) were not introduced until 1948 and were not widespread before the 1950's. (The neutral wire is connected to the larger slot on the electrical receptacle)

 

Here is an indirect quote on NEMA 1 connector standards (2 prong plug and outlet):

 

quote:

Plugs may be and receptacles must be (since 1948) polarized to preserve the identity of the neutral conductor; the blade connected to neutral will be wider (⁵<big>⁄</big>₁₆ in/7.938 mm) than the other, and polarized sockets will only accept a polarized plug in the correct orientation.

 

 

You can connect neutral and ground at the Main service panel because that is the "junction point" where electrical service enters the house.

 

YIKES!  That is a REALLY bad idea, and surely is not sanctioned in the National Electrical Code, or by UL!

 

But in this case weather or not your post says NEVER when you have a bakalite housing you don't have a place for an equipment ground(or a need) . Obviously a pre 3 prong transformer didn't have 3 wires anyway so what is it hurting to connect the neutral and ground together? Your protecting nothing and it hurts nothing for all intents and purposes you can cut the green wire off at both ends and just not hook it up.
But for an already insulated platform it makes absolutely no difference.It's just a way to terminate the green wire and have a back up.If it was a heavy current draw item like an A/C unit I would agree but not a toy train transformer.

David

If you have a green wire in the cord to the KW, terminate it on the metal mounting frame.  That way if there is a short from the coil primary to the core, it will blow a fuse/breaker rather than leave a voltage hazard on the case screws and metal base.

 

John, the neutral and earth ground are always tied together at the entry panel per the NEC.  That is the ONLY place where they can be tied together.  "A premises wiring system supplied by a grounded ac service shall have a grounding electrode conductor connected to the grounded service conductor, at each service…."

I realize they're tied together at the panel, I was commenting on them being tied together at the wall plug.  I'm sure that is NOT OK with the NEC.  I've put three wire plugs on a couple of transformers and connected the ground wire to the transformer lamination.  I've installed several service entrance panels, and I managed to survive the procedure.

John, what did you use to determine the "correct" polarity for the power cord?

 

I replaced a ZW power cord with a 3-pin type, but I think I used the positive in = positive out, which is probably wrong compared to Lionel bricks.  (Maybe) Fortunately, I am not running any bricks on the layout - just on the test/repair bench.

quote:

Obviously a pre 3 prong transformer didn't have 3 wires anyway so what is it hurting to connect the neutral and ground together?

Answer:

quote:

Anything downstream of the main service panel has junctions which may become loose or inadequately connected allowing current to flow back into the neutral, rather than the ground due to inadequate path of least resistance to ground.

I believe the individual who wrote the above accidentally reversed neutral and ground. I think it should read:

Anything downstream of the main service panel has junctions which may become loose or inadequately connected allowing current to flow back into the ground neutral, rather than the neutral ground due to inadequate path of least resistance to  ground.

I think the bottom line here is connecting the neutral and ground lines at the outlet or within your transformer is a no-no.