Hello All:
In attaching a 167 controller to my Z transformer, I was using my voltmeter to see if the whistle button activated any change in my voltmeter reading . Far from an electrical guru I am, so I am asking if I should ecpect any change in the maximum 24.8 volts I see on my meter when I push the whistle button and have the Z at max power? Presently there is no change or inflection. Now the whiste rectifier disc activates a DC surge, correct? So should I be measuring in a different current type? Bottom line is- I am trying to see if my 167 controller will work this Xmas under the tree or be a dud. How can i test it? Thanks for the help and knowledge shared.
Mickey Demian
You need much more of a load than a voltmeter before you will see anything other than the full type-Z voltage. With a train drawing a few amperes, there will be a drop of a few volts in normal operation. This is due to an inductor (choke) in the 167 that will be in series between the transformer and the track. Fortunately, the type-Z has voltage to spare. When you push the whistle button, the inductor will be replaced by a copper-oxide rectifier. Then, as you push it farther, the 167 will put a resistor in parallel with the rectifier, to supply the additional current drawn by the whistle motor. Through all this, the voltage at the track should be roughly unchanged, although, with a diesel horn or a modern electronic whistle, neither of which draws much current, the voltage may rise when you bottom out the pushbutton.