Ok I'm In desperite need of some electrical help. Turning on power to my signal and tortoise switch machine system I've got nothing. I've tested as man spots as possible with my multimeter including the power supply all the way to all the switch machines and some signals. They all show consistent power the whole way through yet nothing is working. The power supply has multiple outlets all that have switches. The main system is all on one switch/section. Structure lighting is on another switch and that is working. So is there a short an how would I know if it is. Does a multiple meter display something for shorts? Any help would be greatly appriciated.
Tyler
It is a little understood electrical fact that a resistance in a circuit will not show a voltage drop unless there is current flowing through it. With a resistive (poor) connection and no load (current flow) the minimal current draw of a meter will not show a discernable voltage drop.
It is likely that the voltage can all but disappear when you attempt to operate an accessory.
Ok so even though everythings wired in parallel, if there is a short circuit some where nothing will work?
Tyler
It appears that my reply is not understood.
It boils down to an understanding and the application of Ohms law, the relationship between voltage ((E) electrical pressure), current ((I) amount of electrical flow) and resistance ((R) restriction to electrical flow).
Basic Ohms law is E=IXR. Without sufficient current flow the voltage will not be changed by resistance.
Increasing current flow through a resistance will create a proportionate voltage drop across the resistance.
A short circuit will create maximum current flow creating a major drop in voltage or a safety feature will shut off power.
OK back to your problem, measurements indicate that voltage is present thought the wiring when no load is applied.
Connect the volt meter as close as possible to an accessory. If you have full voltage, attempt to operate the accessory and observe any voltage change. The accessory will either operate or the voltage will drop. A voltage drop indicates a resistive open between the power source and the volt meter.
A probable cause can be an inadequate (resistive) connection.
The location of the problem can be found by relocating the meter closer to the power source and checking for voltage drop. When no voltage drop occurs the problem is between your last two measurement points. Fix the connection and things should work.
Good luck!
Thanks, I found the problem in a large group of wires.