Single Pulse to Lock and Unlock Using a mechanical latching relay

rotarypower101 · 07-20-2006, 09:42 PM

Hi guys I have a couple of questions about a seemingly easy set of relays.

I have constructed this from a magnetic latching relay and an automotive relay, but cannot maker it work for me.

Can someone confirm by looking at the schematic that this would work?

If I am looking at it correctly, the latching relay would have to reverse coil poarity to work properly, and it is my understanding (from my limited knowledge on the subject) that this is not a function of a latching relay.

Am I correct in assuming that this should not work unless the coil on the latching relay changes polarity and allows a single momentary pulse to bring the relay back to its initial starting position?

And if this is true, what is the need for the extra automotive relay, except for the amperage capability?

Any input on the subject?

It is the second from the bottom schematic labeled “Single Pulse to Lock and Unlock”

http://www.the12volt.com/relays/page5.asp

“Single Pulse to Lock and Unlock Using a mechanical latching relay like the PCB latching relay pictured below on the left, you can use a single negative output to alternately lock and unlock the doors. The mechanical latching relay only requires it's coil to be momentarily energized to change and maintain the opening or closing of it's contacts. The SPDT relay will provide a dedicated negative output for lock when the coil is energized and a dedicated output for unlock when it is not energized.”

YESindeed · 08-16-2006, 02:58 PM

well i cant really understand that diagram but this is how i would do it:

Wiredwrx · 08-16-2006, 03:02 PM

Quote: Originally Posted by rotarypower101

Hi guys I have a couple of questions about a seemingly easy set of relays.

I have constructed this from a magnetic latching relay and an automotive relay, but cannot maker it work for me.

Can someone confirm by looking at the schematic that this would work?

If I am looking at it correctly, the latching relay would have to reverse coil poarity to work properly, and it is my understanding (from my limited knowledge on the subject) that this is not a function of a latching relay.

Am I correct in assuming that this should not work unless the coil on the latching relay changes polarity and allows a single momentary pulse to bring the relay back to its initial starting position?

And if this is true, what is the need for the extra automotive relay, except for the amperage capability?

Any input on the subject?

It is the second from the bottom schematic labeled “Single Pulse to Lock and Unlock”

http://www.the12volt.com/relays/page5.asp

“Single Pulse to Lock and Unlock Using a mechanical latching relay like the PCB latching relay pictured below on the left, you can use a single negative output to alternately lock and unlock the doors. The mechanical latching relay only requires it's coil to be momentarily energized to change and maintain the opening or closing of it's contacts. The SPDT relay will provide a dedicated negative output for lock when the coil is energized and a dedicated output for unlock when it is not energized.”

What are you trying to do.

The original schematic doesn't change the polarity of the automotive relay. It just energizes or de energizes the automotive relay based on the latching relay. The automotive relay is used for it's high current capacity, as you speculated, though it doesn't necessarily appear needed in this situation. No polarity inversion is required, or even used in the schematic you posted.

What are you trying to accomplsih, so that we can help you with this.

Michael

MatrixPC · 08-16-2006, 03:40 PM

Maybe this help
From http://www.the12volt.com/relays/page5.asp#lsp