16V AC wiring

[Anonymous]

My HO layout is block wired into four sections. Each section has it's own H/Held throttle. The power source is a Gaugemaster 16v AC Transformer. The problem is that the power to all sections cuts out intermittently i.e. some sessions works fine, then without warning next "switch-on" nothing I can do makes it go. Have checked all my wiring exhaustively, every obvious thing.After 40 years in the Hobby I am stumped! Seems like a short circuit but where & how? All track, wheels etc are spotless. Any suggestions are most welcome.

[Don Gibson]

OPENS and SHORTS look alike - everything stops. A 'short' however will normally pop a fuse.

Put a couple of 16v - 24 volt bulbs into your circuit (ONE in Parallel / One in Series) - Voltage (parallel) should be the Green the other (series) Red.).
Cheaper than meters and will tell you what you want to know: OPEN or SHORT.

Tracking down a daisy-chain of connections will require a meter.

[cacole]

If all sections are cutting out at the same time, then the problem seems to be originating with the main power transformer. Does it have an overload circuit breaker that automatically resets? If so, there may be an overload causing it to trip off periodically, and then it's resetting itself when it cools down. If there is no circuit breaker of this type on it, what about a fuse? Change the fuse, if there is one, and see what happens. Although it's not very common, sometimes a fuse can have intermittent contact due to vibration.

[nfmisso]

Here is a possibility not mentioned above: the gap between adjacent blocks may not be perfect, creating a short from the transformer, thru one hand held, along the rail, thru a second hand held, back to the transformer.

The gap could also be bridged by a metal wheel, lighted passenger car or locomotive......

[Eriediamond]

I'm learning something new here, I guess as I thought HO was powered by DC, not AC. Does the hand held throttle convert the AC to DC? Also my limited knowledge of electronics tells me that each block of an AC system has to be in sync with each other or a short will occur when the loco passes over the the rail gap. In other words if a rail in block A on one cycle is positve, the the same rail in block B has to be positive also.

[cacole]

Yes, HO is DC powered, except some German models, but your power transformer is AC, and that current is then rectified and filtered into DC. Even a Model Rectifier power pack has an AC transformer in it to lower the voltage from 110 to around 16 Volts, and then it is converted into DC. That's why Model Rectifier power packs have AC accessory terminals that are rated at 16 Volts.

[Don Gibson]

PROBLEMS with AC (or DC) wiring are the same. Opens, Shorts, or Intermittents - and even Polarity.

A short in your Transformer would pop a fuse or burn it up, since it's plugged into 110 v.
so your connections are suspect.

You can hire an Electrician for $50hr. but it's cheaper to borrow $10, buy a Meter, and USE it.

[Anonymous]

[:)]thanks guys, I am taking your advice & will obtain a multi-meter (I only have a DC Meter at present) but here in Australia not many modellers seem to use tethered walk-around throttles, hence my difficulty. The Gaugemaster 16vAC t'former is new & power output is normal. There seems to be a backfeed via the common return wire meaning that after I disconnected the feed wire to the problem section it now works! This however has not solved the root problem of a short of some description.