Where to wire in Volt and Amp meters?

I'd put them on the output of the ZW. The output of the TIU is NOT a "pure" sine wave--- The ZW output is, so the meters will read accuratly. The readings at the output side of the TIU will not be accurate.

Wow, that you for that information.  That would have driven me nuts trying to figure out why the strange readings from the TIU output vs from the ZW.  

I know there are much better transformers to use but these 2 ZW's have history.  One of them was given to my brother and I for Christmas 1958 along with our first set of trains.  The other one was given to me by my cousin who did the unthinkable - he gave up his trains when he discovered girls!

Thanks for the good info.

Ed

No need to apologize for using ZWs. I have four of them in use!

Some digital meters are designed to read "true RMS". If so, a complex waveform will be read correctly. True RMS meters are usually more expensive, however...maybe you can determine if your meters are or not.

I would decide how many places the voltage was important to know,then run individual wires to a rotary switch located nearby,wire one side of the voltmeter to the switch center and the other side of the meter to the common. Be sure to leave one position on the switch blank so the voltmeter has a neutral spot Hope this helps. Charlie

Considering what I paid for them I am 99.99% certain they cannot read a complex waveform.  But I am sure they will provide the info I need from them.  

Thanks,

Ed

Fastman

That is a great idea.  I actually do the same thing for turning power on and off for the roundhouse sidings.  

Thanks,

Ed

You may already know this.....

but keep in mind that Amp Meters are wired inline[in series] on the Hot wires and Volt Meters are wired across the line[parallel]. The full railpower load of the metered power district will be passing through the Ammeter, so the wires connecting the meter must be the same size as your Hot Bus conductors.

Smaller gauge wires can be used for Volt meters which simply connect across the Hot and Common.

Dewey,

Admittedly I am no electrical genius but I actually did know that the wire gauge going thru the amp meter needed to be the same as from the power source otherwise a weak and potentially dangerous point would be created.

But i didn't know that the same logic is not applicable for the volt meters.  I guess I never gave the volt meters much thought other than using the same gauge just for wire consistency purposes.  But after reading your post I understand the logic.

Just goes to show there is always something new that can be learned playing with trains.

Thanks,

Ed

Analog Meter back side wiring, the connections are the same for digital. Top row is three Volt Meters, bottom Amp.

Photo shows a three power district hookup, the colored and black wires  are the Hot and white is the Common. Heavier gauge Hot wires are in from transformer, thru AAC meter and back out distributed to railpower. Short jumpers from Amp Meter's inbound Hot energize the Volt Meter's hot side and a white Common connects direct to first meter then daisy-chains to others to complete the across the line circuit.

In my case, the meters connections are extended from a Layout Railpower Distribution strip which organizes and distributes the transformer's power to the layout.[2nd photo].

 As a review, just so folks know how to wire in these meters from an electrical point of view...

HEHE!

Picturing some circuit protection would have been good as well Rich, I wouldn't use these old ZW transformers without protection for the equipment on the track.

I had three pw ZWs supplying 5 power districts before changing over to five 180 PoHos. I was not at all comfortable with protection by the ZW's original breakers.

So, the ZWs were protected by connecting to a recycled Autolite cartridge fuse holder block with both 7 & 10 amp fuses. At one point I tried a "Breaker Box" equipped with W28-XQ1A-10 Potter-Brumfield breakers from Mouser. They were a little slow to suit me so I went with the faster fuses.

Thanks everyone for the advice, especially the pictures.  I am very comfortable now with how it needs to be done correctly.

As for the fusing.  I know the ZW breaker won't do much to protect anything downstream which is why I am already using fast blow glass fuses along with TVS(s) placed in multiple places for each power district. 

I remember getting some help on the ZW breaker from a fellow on another forum years ago named Al whose last name I forget.  He told me that the break time for a ZW internal breaker was just about long enough to cook a 2 minute egg !  He passed away a few years ago but I will always remember all the friendly and helpful advice he gave getting back into the hobby.  

Thanks everyone,

Ed

ammeters can be problematic for a lot of reasons. you can get a proximity meter that reads the magnetic field around a wire a good auto parts store should have one . About $20.00 and it is portable and not in the circuit. Hope this helps

I have both Fluke and Sperry clamp-on meters at the Shop, but for Toy Train monitoring the $10 wired panel meters serve well.  They typically have 1-1/2 to 2-1/2% variation but that is not crucial for Toy Trains. 

Another Great Lesson.

Thanks

Ed, I'm thinking around the same lines as you for adding some meters for volt and amp info off of my old ZW...just make sure the LED readout meters you get are the "AC voltage" type and not DC voltage reads.

Watch their min and max limits too....I might just go simple anolog readout types.

Bob,

I was careful to get the AC meters.  They do make combo AC Volt/AMP led meters which would have been great because they would take up less space.  Unfortunately I could not find a combo unit where the measured voltage range started at 0.  For some reason it seemed like they all started at 80 volts. So I ended up going with separate amp and volt meters.  I couldn't afford the kind of meters that would provide precision measurements but these meters will be close enough for troubleshooting purposes.  I thought about using analog but I thought the digital readouts would be easier for my aging eyes to see.

Ed

Dewey, agreed, those meters are good enough and even being just a tad off{if it's that much really} it's still good enough for the hobby. Anyone needing more precise measurements would require far better equipment, and probably not all the time at that....those shown above would do nicely.

Question- why 5 circuit monitoring?....4 main power and one accessory?

The digital voltmeters, even though not "True RMS" will read fairly accurately when the voltage is at max like it is for TMCC since the wave form is nearly a full sine wave. And at lower voltages for conventional, it really doesn't matter what the number is, the repeatability will be accurate and useful.

So all good. Digital or analog...whatever works for you.

Bob

Those five were all monitoring AC Railpower Districts on a high "Airborne" twin shelf shelf operation. No live accessories or lights. Dismantled in '08.

On a very small far simpler round-the-wall attic layout having two power districts, I monitor the Railpower with two pair of VAC/AAC meters and the Tortoise motors with a VDC meter[shown on top right in photo-dimly displaying 12 VDC ]. Although I installed an accessory and a lighting Bus and smaller AC transformers, I have no powered accessories or even connect the lighting on this stagnant layout [I hope temporarily] and, at this point, doubt that I will. 

Voltmeters and circuit breakers wired to the TIU output channels

On my DCs control system I have voltmeters and circuit breakers on both TIU output channels. The voltmeters are used to provide a relative indication of the AC output voltage. The circuit breakers protect the outputs to the track. I also have circuit breaker protection attached to the TIU input channels. Wiring is 16 gauge.