91 Circuit Breaker!!

[davidam]

Bob Nelson

Could you recomend what type of transient voltage superssor should be used for kw's & type v transformers. I have experienced a melt down  of an electronic engine running on the  V transformer. By the way I am  not good with electronics. I wolud appreciate any advice you can give. Thanks

Dave Marconi

 

 

[lionelsoni]

Vishay 1.5KE36CA.  Wire it across (in parallel with) the track.  It is a bidirectional unit, so polarity doesn't matter.

[jsonova99]

I was planning on wiring TVS diodes right across the terminals on the transformer (ZW & 1033), at least until I have a more permanent setup.

[bfskinner]

Request for update from Bob "lionelsoni" Nelson

Bob, if I am reading the current Mouser catalog correctly (as of Feb 2013) this part is not available -- which is not quite the same thing as saying they cannot supply a substitute.. Could you recommend a suitable  substiture, and perhaps re-explain what the various essential terms of the part number mean (such as the code that specifies bi-directional)  and the voltage values within which the device will function properly in toy train applications?

Any help you can give that will make it easier for a layman to locate and acquire an appropriate TVS diode will be greatly appreciated. Thanks in advance.

[lionelsoni]

Here is a link:

http://www.mouser.com/Circuit-Protection/TVS-Diodes-Transient-Voltage-Suppressors/_/N-5g3gZscv7?P=1yzv44x&Keyword=1.5KE36CA&FS=True

The "1.5" is the peak power rating in kilowatts.  The "36" is the nominal peak voltage.  The "CA" means "bidirectional".  "A" alone means unidirectional; but you don't want that.  There are three voltage ratings to consider:

Operating voltage--30.8 volts.  This should be no less than the RMS voltage times the square-root of 2, which is 29.7 for 21 volts RMS (ZW).

Breakdown voltage--34.2 volts.  This is the voltage at which the TVS will begin to conduct.

Peak voltage--49.9 volts.  This is the voltage to which the TVS will limit the circuit.

[bfskinner]

Thank you, Bob

 

That was exactly what I was looking for. Don't know why I couldn't find it in the Mouser website except that they have a lot of very similarly-labled items and I guess my bifocals just weren't up to it.

[BayWindow]

The original prewar and the first postwar which except for high and low connections looks like the prewar is a magnetic breaker and VERY fast.