From what I read, old whistle relays should not operate below 20V AC/60 cyc. due to the frame/ring set up which shorts out the AC magnetizing component.
Problem: I've got a relay that will close at 14V AC/60 cyc (without DC application) and operate the whistle solidly just above this voltage.
The only two possibilities I can guess at are that:
1. The coil might have an internal short which would lower the effective resistance/impedence and cause the relay to operate at an AC voltage of less than 20V.
2. The coil/armature might have a small amount of residual magnetism (which would mimic the effect of a partial voltage being applied) which might lessen the level of actual AC voltage needed to close the relay.
Only guessing, comments would be appreciated.
Thanks.
I would recommend you re-post your question in the Classic Toy Trains forum. That's where the three-rail and American Flyer crowd usually gather.
Sorry I can't help. Modern small-scale noise technology is all solid state. OTOH, the closest thing to a train whistle in my house is a four-chime wooden whistle-flute - and I don't blow it when operating my layout.
Chuck (Modeling Central Japan in September, 1964 - in HOj 1:80 scale)
The whistle/horn relays need a small DC voltage to close the contacts. AC voltage alone will not operate the relay.
"Residual magnetism" would not pull the contacts in, but it may hold the contacts in once a DC voltage was applied.
Put a DC voltmeter across your lockon terminals and see if there is any DC voltage on the tracks. It does not take much DC to operate the relay; little more than 1 volt will cause the relay to close.
What transformer(s) do you use to operate the trains?
Larry
The Lionel specification is not to operate below 28 volts, 60 hertz.
How are you generating the voltage and how are you measuring it?
Bob Nelson
Larry and Bob,
Correct, the writeup I was referencing was 28V/60 cyc.
I am using a Postwar ZW with Lionel Fastrack with a prewar 1689W tender.
Just did a double check. With the tender on the track and the voltmeter probes on the rails 2" from the tender wheels, the relay picks up at 14.5V AC with no DC indicated.
Am I missing something basic here?
Tad
The 14.5 volts you measure is about the minimum voltage for the whistle motor to run. If you have not already, take off the tender body and make sure the relay contacts are not stuck shut with no power applied. If the relay picks up with no DC voltage applied, it sounds like it is defective. Swap it out with a known good relay and see what happens.
Try switching throttles on the ZW, especially trying the 2 inner throttles with no whistle control.
Larry,
All previously described testing was done with the interior exposed to check the performance of all components. The contacts were free at all times.
Testing on the other ZW throttles yielded the same results, pickup around 14-15V AC with no measured DC. Also tried a different transformer with similar results.
Resistance of the relay coil measured out at 5 ohms. Measured several other coils and got 12 ohms for each. Don't know what the norm is.
Haven't tried a swapout yet.
Tad,
If the wire gauge and number of turns on all the relays is the same, then the low resistance reading you get on the present relay indicates a shorted coil. The 12 ohm readings would be a nominal reading for a good coil.
One of the 12 ohm relay coils tested was from a pre-war tender and the other from a post-war one. With the same 12 ohm reading between pre-war and post-war, I'm guessing the turns/wire size is probably the same for the two good and the one bad.
I'll try a swap out to make sure everthing else works. If everything works with a good coil, I'll unwind the bad one just to find out why it shorted. First bad one I have ever run across.
Regards,
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