View single post by Si.
 Posted: Thu Nov 24th, 2016 09:17 pm
PMQuoteReplyFull Topic
Si.



Joined: Thu Feb 23rd, 2012
Location: London
Posts: 5244
Status: 
Offline
" The culprit was a single strand of wire that bridges across the switch contacts.
I forgot to put my high-power spec on when soldering the wires "

Hi Peter :wave:

As John has said, the reason he trashed an A.C. operated Peco point-motor, is basically because it was wired up incorrectly.

- - - - - - -

" It doesn't take much to burn out the coils as I have found out in the past."

Peter, I would be interested to know HOW you came to burn a Peco point-motor, using the A.C. stud & probe method ?
I can't imagine for one moment that this could be an easy thing to do !
My guess is you were using cheap switches, right ?

The great thing about using A.C. with stud & probe operation, is that the coil can't possibly be energized for any significant amount of time, unless of course you purposely hold the probe on the stud for ages, which seems highly unlikely.

Even using A.C with push-button switches, providing of course they are correctly specified, is WAY less likely to burn out a coil compared to using high D.C. current, which inevitably acts like an arc-welder ! on the switch contacts.
Whether the D.C. is from a C.D.U. or from a regular P.S.U matters little.
The life-expectancy of ANY switch or stud & probe setup is far far greater using A.C, than with contact damaging D.C.

- - - - - - -

On the Jaycar switches.

I used exactly the same switch, in a DIY throttle, some years ago.
It was running really small N-scale motors in 0-6-0s on the flat, pulling 3 cars tops.
I burned out about 3 of the Jaycar push-button switches, before giving up & replacing them with something 'fit for purpose'.

I have specified & installed hundreds and hundreds of switches over the years, both professionally & for hobby use.
The Jaycar push-button switch, literally sticks in my mind, as being the worst switch I have ever used.

It isn't well designed or manufactured.
I've never seen them used in any 'decent' product.
Witnessing them in action for point-motor operation as well, they fail very very quickly.
Their main selling point is, they are cheap, real cheap !
That seller ^^^ is overcharging BTW.

I found a good use for my remaining stock of them, a few years back.
They helped fill up the giant hole in Essex, where London dumps all it's garbage !

:moose:

Si.

The only C.D.U I would ever consider, is one that is operated by an S.C.R individually installed with each turnout.
Complex though.
By the time you've paid for & done all that, or bought a proper expensive push-button switch, you could probably have afforded a slow-motion point motor.
&
That's the 'Catch-22' of it all & why 9 times out of 10, a cheap job with economy parts, leads to unreliability & ultimately failure of switches and/or coils.
Or
You could use A.C with stud & probe...
...and have CHEAP as well as RELIABLE.

I could recommend some push-button switches, if anyone is interested.
The problem is you'll never buy them, they are way way too expensive !



____________________

' Mysterious Moose Mountain ' - 1:35n2 - pt.II
http://www.freerails.com/view_topic.php?id=7318&forum_id=17&page=1

' M:R:W Motor Speedway !!! ' - 1:32 Slotcar Racing Layout
http://www.slotforum.com/forums/index.php?showtopic=59295&st=0&a
Close Window