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LED Indicator with a DPDT Switch

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  • Member since
    February 2019
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LED Indicator with a DPDT Switch
Posted by Hawks Rule on Friday, April 12, 2024 2:45 PM

Hello All

I have a DPDT switch which I added to my layout to operate both DC and DCC.

The wire connections are straight forward and easy to add to the switch.

I have tested the switch in both DC and DCC, they work very well.

On my panel, where the DPDT switch is attached, I would like to also add 2 LED lights, one for the DC side and one for the DCC side to light up when one of the functions is working.

I'm not sure how to go about it.

Any help and assistance would be greatly appreciated!

  • Member since
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  • From: Dearborn Station
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Posted by richhotrain on Friday, April 12, 2024 3:14 PM

One way would be to wire a pair of bi-color LEDs to the center terminals of the DPDT switch. One would be lit green and one would be lit red at all times.

Rich

Alton Junction

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Posted by Hawks Rule on Friday, April 12, 2024 3:37 PM

richhotrain

One way would be to wire a pair of bi-color LEDs to the center terminals of the DPDT switch. One would be lit green and one would be lit red at all times.

Rich

 

Hello Rich,

Is there any other way to connect the 2 LEDS, so that they are only on when the toggle is in either position, instead iof all the time?

 

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Posted by AEP528 on Friday, April 12, 2024 3:45 PM

richhotrain

One way would be to wire a pair of bi-color LEDs to the center terminals of the DPDT switch. One would be lit green and one would be lit red at all times.

Rich

 

The DC side would only be lit with a non-zero voltage, not all the time.

If the OP is okay with that, then all is good. But DC throttle "off" would look the same as DCC powered off.

To solve the DC problem, the simplest way would be to get a triple-pole double-throw switch, and use the third pole to drive the LEDs using a separate power source. The switches are a few dollars each.

Any other means adds complexity.

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Posted by Hawks Rule on Friday, April 12, 2024 3:52 PM

I would like to make something like this:

Note: two green LEDs, one for DC and one for DCC.

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  • Member since
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  • From: Dearborn Station
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Posted by richhotrain on Friday, April 12, 2024 4:11 PM

Can you provide a diagram of how the DPDT is currently wired?

 

Is it DCC on one end and DC on the other end with the rails wired to the center terminals?

Rich

Alton Junction

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Posted by Hawks Rule on Friday, April 12, 2024 4:34 PM

richhotrain

Can you provide a diagram of how the DPDT is currently wired?

 

Is it DCC on one end and DC on the other end with the rails wired to the center terminals?

Rich

 

 

Yes, exactly like you described.

  • Member since
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  • From: lavale, md
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Posted by gregc on Saturday, April 13, 2024 5:01 AM

seems like you would need a 3rd pole on the switch or some circuitry.   

Looks like RPC Electronics DC/DCC Switch Panel is what you want ($12)

looks like the RPC board is nothing more than a 3PDT switch.   That 3rd pole powers one of the 2 LEDs

greg - Philadelphia & Reading / Reading

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Posted by richhotrain on Saturday, April 13, 2024 10:28 AM

I'm going to stray a little bit from the main topic to express concern for powering the same layout with two different power sources, DC and DCC. 

If DC and DCC locomotives are going to operate on the same trackwork, I think that is risky even with toggle switches and LED warning lights. At a minimum, it would seem to me that at the end of each operating session, the locomotives should be parked on isolated and gapped tracks, separately for DC and DCC. At least that way when the next power up action occurs, no locomotives are "live" until the desired power source is selected and the parking track is activated.

Rich

Alton Junction

  • Member since
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  • From: Dearborn Station
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Posted by richhotrain on Saturday, April 13, 2024 10:30 AM

I have no experience with triple pole, double throw switches, so I will be interested in how such a switch is wired to meet the OP's panel requirements.

Rich

Alton Junction

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  • From: Westford MA
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Posted by Tophias on Saturday, April 13, 2024 10:45 AM

richhotrain

I'm going to stray a little bit from the main topic to express concern for powering the same layout with two different power sources, DC and DCC. 

If DC and DCC locomotives are going to operate on the same trackwork, I think that is risky even with toggle switches and LED warning lights. At a minimum, it would seem to me that at the end of each operating session, the locomotives should be parked on isolated and gapped tracks, separately for DC and DCC. At least that way when the next power up action occurs, no locomotives are "live" until the desired power source is selected and the parking track is activated.

Rich

 

+1 Yes

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Posted by richhotrain on Saturday, April 13, 2024 10:52 AM

I pulled together a couple of drawings that illustrate the numbering of the 3P2T switching numbering protocol.

Alton Junction

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Posted by Hawks Rule on Saturday, April 13, 2024 1:44 PM

richhotrain

I pulled together a couple of drawings that illustrate the numbering of the 3P2T switching numbering protocol.

 

thank you all for your input. I will look into this type of switch as well.

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  • From: lavale, md
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Posted by gregc on Saturday, April 13, 2024 1:58 PM

richhotrain
interested in how such a switch is wired to meet the OP's panel requirements.

 

722

greg - Philadelphia & Reading / Reading

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