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Reverser reaction time

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  • Member since
    September 2002
  • 7,486 posts
Reverser reaction time
Posted by ndbprr on Thursday, December 27, 2018 3:50 PM

I visited a Digitrack controlled layout that when the engines entered and exited the reverser section they slid for about a second before the polarity allowed the engine to not be shorted.  Is this typical of reversers or was this a problem with his layout?  Is there a superior reverser in regard to reaction time and switching polarity?  Thank you.

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Thursday, December 27, 2018 6:17 PM

 This was either the reverser not properly set or the layout wiring not up to snuff. Depends on what autoreverser was being used, some are adjustable and if this layout used one of those sort then it wasn't set up properly.

                                  --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    December 2004
  • From: Bedford, MA, USA
  • 21,483 posts
Posted by MisterBeasley on Thursday, December 27, 2018 9:21 PM

That's why I prefer a solid state reverser over a relay based reverser.  The electronics are too fast to notice.

But, they still should not take as long as you've described.  There might be some wiring issue in the loop.

It takes an iron man to play with a toy iron horse. 

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Thursday, December 27, 2018 10:47 PM

 The reaction time of a relay moving the contact is also really too fast to notice. Any and all delay is in the circuit deciding to power or remove power from the relay coil. Can't find a specific data sheet but I did find a training course for using an oscilloscope to measure the contact opening and closing delay at various voltages (if you go to the low side of the relay coild rating it unsuprisingly takes longer), both with and without a quench diode (anti-parallel diode across the relay coil to prevent BEMF feedback into the switching mechanism - the driver transistor or pushbutton switch or whatever) and the typical delay is a few ms at worst. That's not enough for there to be a noticeable blink of the headlight.

                                            --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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