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Pulse width Modulation control
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 Posted: Sat Apr 20th, 2013 08:09 am
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Tramcar Trev

Joined: Sat Mar 16th, 2013
Location: Gordon ACT, Australia
Posts: 398
I have split my tramway into 2 sections; east and west. Both sections are insulated form each other and have their own PWM controller. Ok so my question is this: when a Tram car passes from one section to the other the trolley wheel goes through a section isolator (as light rail types call them, Cut off being the tramway term) there is also a break in the rails, as I say both sections are isolated. But from what I can make out it is the negative that is modulated and I'm just a tad concerned that I'm going to create a short circuit or blow up one or other of the controllers when a tram passes over the joint as the wheels will allow current to pass from one section to the other i.e. up the front wheels and out the back wheels or vice versa...
Someone here will know if I'm going to get the big blue flash or whatever...

There once was a man who said Damn!!
I perceive with regret that I am
A creature that moves
in predestinate groves
I'm not a Bus, I'm a tram
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 Posted: Sun Apr 21st, 2013 03:29 am
2nd Post
Herb Kephart

Joined: Thu Jul 19th, 2007
Location: Glen Mills, Pennsylvania USA
Posts: 5870

The guys at the East Penn trolley group (Google) found out early on with their modular layouts and multiple control positions that EITHER the rail, or the wire must be electrically continuous.

I don't think that pulse power would change that in any way.


Fix it again, Mr Gates--it still works!"
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