e unit noise

[ajelectric]

I have 2 loops of track powered by a modern ZW with two 180watt bricks.  Inside these two loops is another loop powered by a post war ZW.  All of the loops are interconnected, transformers phased, etc.

The modern ZW work fine running engines using the electronic "e" units, however when I put some of the older engines with the solenoid type e unit, the e unit make a buzzing noise in both forward and reverse while the engine is running on the outer two loops with the modern ZW.  It's not as loud as when in neutral, but the sound is noticeable.  When I run these same engines on the inner loop with the Post War ZW, the e units are much quieter.  

Any help,insight or ideas as to why the e units are noiser with the modern ZW would be greatly appreciated?  Thanks, Alan

[Berk765]

I'm not shure about why they are noisy, they just are. I have several postwar steamers and some are quieter than others some get louder or quieter as you raise or lower the voltage while in neutral. Other than that, its normal, and I wouldn't worry about it too much.

[Sturgeon-Phish]

The noise is from the 60 hertz cycle of the ACvoltage and is part of the charm of post war trains.  Some coils are louder than others where that have gotten hot and expanded, and the windings are not as tight and the vibration is more pronounced.

[lionelsoni]

Until someone reverse-engineers a modern "ZW", we won't know what they're doing to control the voltage, because Lionel isn't talking.  Your experience is evidence that the result isn't a sine wave.

Running between differently-powered blocks, even if "phased", can be a fire hazard.  I can't speak for your modern "ZW"; but there is no circuit-breaker protection against the faults that can occur among any multiple blocks in your inner loop.  By the way, such faults are avoided only if the voltage, frequency, phase, and waveform are identical between blocks.  From your e-units' behavior, we know this is not the case between the old and new ZWs.

[ajelectric]

Bob,

Thanks for the reply - That is what I figured, there is not a true sine wave which is causing the e-unit to chatter as it does not maintain a magnetic field.

 You mentioned that running block with different power sources (modern and Post War)may be a fire hazard.  Is there a safe way to do this?  Do you know of any good books that cover wiring blocks?  Thanks again, Alan

[lionelsoni]

Alan, when I say different, I mean especially running between the multiple outputs of a single transformer like a (real) ZW, not particularly between modern and postwar.  The idea is to keep each train under a single control, no matter where it goes on the layout.

The safe way is to use (electrical) switches to assign each block to one of as many different transformer outputs as you want to use.  In the simplest case, this is two, for example, A and D, the two main outputs of a ZW.  You can do this with a single-pole-double-throw switch per block.  Using a center-off switch also lets you park a train in the block, with no power.

Note that, with this scheme, you can have far more blocks than transformer outputs, if you need or want them.  This can be handy in transferring trains between loops, when you might need to power different sections of both loops from different controls.

I find that two controls and two trains are about all I can handle at one time.  If you feel up to running more than that, there are simple ways to wire multiple toggle switches to select up to 4 sources with 2 switches and up to 8 with 3 switches.  There are also ways to do this kind of thing for multiple operators at multiple positions.

[Fordiesel69]

E unit noise or buzz is just a fact of life.  I have one e unit that is silent and it is just luck.  The chatter comes from the coil stop, the plunger too high and out of the electromagnetic field.  If the coil stop and plunger was brand new and perfectly machined the chatter would be ever so minimal.  Pinball machines have many coils that do this until they went to DC voltage.