Lionel LW transformer shows voltage when off

Get rid of the digital meter and get one with a needle. It will give more accurate readings. Or put a light bulb across the posts and put your meter on that.  Tiny amounts of leakage or inductance will show up on digital meter. But there is no power there. It does not mean anything.

@David Johnston posted:

Get rid of the digital meter and get one with a needle. It will give more accurate readings. Or put a light bulb across the posts and put your meter on that.  Tiny amounts of leakage or inductance will show up on digital meter. But there is no power there. It does not mean anything.

This is the answer. It IS  your meter.

The Lionel transformer is a unique design and the LW,  like other multi-control transformers, when the throttle is 'Off' you still have about 5 volts on the track between posts A and U.  Pushing the whistle gives a surge of DC voltage to pull in the whistle relay, and then a holding voltage to keep it pulled in while the voltage coming from the throttle runs the whistle motor.  If you have the schematic available, you can determine what voltages to expect between each post.  Get Greenbergs Repair and Operating Manual for Lionel 1945-69.

Thx guys

FYI - found these pics of the LW manual. Says A to U is 8 to 18 volts, which was Lionel's design target. So as @CALNNC wrote, you should expect to see some voltage A to U when handle is at off position.

@CALNNC posted:

The Lionel transformer is a unique design and the LW,  like other multi-control transformers, when the throttle is 'Off' you still have about 5 volts on the track between posts A and U...

No, the LW is no different than any other postwar transformer. The wiper comes completely off of the secondary in the "off" position. Any voltage reading while "off" is due to the combination of a cheap meter and its reading of an unusable capacitance voltage. As soon as you put any load on it, there is zero volts.

@MED posted:

FYI - found these pics of the LW manual. Says A to U is 8 to 18 volts, which was Lionel's design target. So as @CALNNC wrote, you should expect to see some voltage A to U when handle is at off position.

No, the wiper comes completely off of the secondary in the "off" position. Any voltage reading while "off" is due to the combination of a cheap meter and its reading of an unusable capacitance voltage. As soon as you put any load on it, there is zero volts.