Bachmann Online Forum

Discussion Boards => General Discussion => Topic started by: Train res on April 23, 2020, 04:25:11 PM

Title: relay
Post by: Train res on April 23, 2020, 04:25:11 PM
I have read that instead of using an atlas snap relay to install indicating lights for turnouts , you can use an inexpensive relay
I purchased the relay number suggested but was surprised it had 10 pins 8 + 2
Does anyone know how to wire this dpdt relay to an atlas switch machine to run red/green  led lights on an atlas turnout relay # is EC2 12TNU   MEXEM a general puose 12 volt 2 amp
thanks
Title: Re: relay
Post by: rich1998 on April 23, 2020, 10:16:14 PM
Just look for the data sheet online. Some might have the pin layout on the case. A simple style relay I used many times over the years.
Solder a diode across the coil pins for reverse surge protection. I usually use a 1N4001 if controlled by a transistor or some digital device. You might not need one.

Rich
Title: Re: relay
Post by: jward on April 23, 2020, 11:10:28 PM
Unless you have a latching relay you are going to have to design some sort of stick circuit to keep the relay energized when the switch controller button is not depressed. It isn't difficult to do, but it's going to use up at least one set of contacts on your relay. The Atlas snap relay is basically a switch motor that throws contacts instead of  switch points, so it doesn't have that problem.
Title: Re: relay
Post by: Len on April 24, 2020, 02:06:01 AM
If you have the 10 pin 8+2 relay it's a twin coil latching relay. One coil sets the common connectors to one set of connectors. The other coil switches the common to the other set of connectors. The coils are designed for pulsed 12VDC operation, not continous current flow. One you trigger the coil, the relay switches and latches, so current doesn't have to be left on through the coil. You'll need a couple of buttons, or a SPDT Momentary Contact toggle switch, to control it without burning out a coil.

Len
Title: Re: relay
Post by: Trainman203 on April 24, 2020, 11:11:36 AM
Man.  Electrical engineering.  Glad it's not all absolutely necessary to make a train roll.
Title: Re: relay
Post by: jward on April 25, 2020, 06:47:25 PM
Don't know why people are so afraid of layout wiring. If anything DCC has complicated things.

Under the old DC system there were only 3 basic circuits repeated as necessary:

1. speed controller to track via block control switch.

2. power supply to switch motor via switch control box or momentary DPST switch.

3 Reversing section, Speed controller to track similar to &1, but with the addition of an auxilliary reverse switch {DPDT}

Anything beyond that was an optional complication chosen by the owner of the layout.

Title: Re: relay
Post by: Len on April 25, 2020, 07:20:03 PM
And even with some the minor wire splicing involved witn Bachmann turnouts, the Atlas 'Snap-Relay' makes it easy to add indicator lights to the control panel. You can even wire trackside lights in paralell with the control panel lights very easily.

Len