Does a PW ZW 275 watt transformer put all its wattage to any one post or one quarter of its wattage to each post?
Though I’m not sure, it would seem like it would supply all its voltage to each post, then the more you put on each, the total voltage goes down in each of them. Though, thats just my guess.
The ZW has only one core which is tapped by four different wipers.
The entire current(amps) can go to one post, or it can be divided into any ratio between the four posts.
This is different from the modern ZW, which actually can be configured with a separate transformer core for each output, with each transformer core able to supply either 135 or 180 watts.
By the way, the actual maximum output of the PW ZW is more like 180 watts-275 watts is the input.
The voltage to each output terminal depends (mostly) on the associated handle position. The power put out from each terminal is the product of the voltage at that terminal and the current drawn from it. The total power put out is the sum of the powers put out at the individual terminals. That total is the quantity that the power ratings are referring to. So each terminal could be putting out some fraction of the rated power; or one of them could be putting out the full rated power with none left for the others.
The circuit breaker limits the total current drawn from the four terminals (to 15 amperes), which is related to the total power put out in only an approximate way. For example, the service manual says that it can supply 180 watts at 14 amperes, which implies that the controls are set to about 13 volts. However, you could set the controls to 21 volts and put out 315 watts at 15 amperes before tripping the breaker. (For a very short time, this is okay.) On the other hand, with the controls set at the minimum 8 volts, you will get only 120 watts before the breaker trips.
As you supply more current, the voltage does drop on all the outputs, but not a lot. A transformer’s output voltage is mostly independent of the load. But it does have some effective series impedance that causes some voltage drop, in the same way that track and wiring resistance cause voltage drop. This can be a valid reason for using separate, perhaps smaller, transformers instead of one big one, to keep trains from affecting each other’s speed.
A note on terminology: The core of a transformer is the magnetic circuit, traditionally made of iron laminations, as distinct from the windings. There is some ambiguity in referring to toy train “transformers”, since the actual transformer is a component (or components), comprising core and windings, inside what we loosely refer to as the “transformer”
Thanks guys.