how do I use a momentary switch break a circuit? 4

[bigDummy79]

I need to use a momentary switch to break a resetable circuit, is there a nonresetting relay I can use? Please advice I am totally new at this.

 

[nbucska]

The relay has an extra normally open [NO} contact which is parallel to the on switch .which is [NO], too. If you push it long enough for the relay to pull in, the extra contact energizes the coil and it stays ON.

The normally closed [NC] reset switch is in series with the coil. If you push it long enough for the relay to release, if will stay reset.

Plesae read FAQ240-1032
WEB: <

http://geocities.com/nbucska/>

 

[VEBill]

If don't want to use a NC switch to reset the relay, then just kill the system power (same thing, but without the extra switch).

Similar systems will often have an indicator light in parallel with the relay coil and the wording next to the light will say something like, "Protection Tripped - cycle power to reset".

 

[waross]

The first few generations of personal computers would survive a normal power failure, but if the power came back on while the hard drive was winding down the data was toast. As I remember, the old XTs were suseptible but the ATs were OK. In a rural area with lots of birds and tree branches tripping the reclosers there was a whole lot of reformatting going on. We used a relay with one set of contacts in parallel with the push button. When the power failed the relay would drop out and stay out until the button was pushed to reset the relay. The people on the computers waited until the hard drive had time to stop before resetting the power and had no more problems.
You could add a normally closed button in series with the coil and get the functionality you need.
yours

 

[bigDummy79]

the solenoid is a 4-5amp 12v DC. Who makes the relay you were using. That sounds like a perfect solution.

 

[maximka]

You local RadioShack has a few. If you are breaking 5 Amp, go for 10A rating, something like 12VDC/10A DPDT Plug-in Relay Model: 275-218 | Catalog #: 275-218

http://www.radioshack.com/search/index.jsp?kwCatId=&kw=relay

good luck.

 

[ScottI2R]

Ah waross,
Thanks for the memories! I remember XT's being switched on again too soon and the resulting "Boot Disk Failure"!!!! Seagate ST-225's (20 WHOPPING MB)if I recall. I have a pair @ home that I use for bookends. We came up with the same solution back then to prevent the problems.

Scott

In a hundred years, it isn't going to matter anyway.

 

[bigDummy79]

I bought the DPDT relay from radio shack but I am mot sure of how to wire it in to get the desired results. In essence I need a circiut breaker to be activated by a momentary switch. The solenoid functions in its deenergized state. It will start off in an energized state and when used switch off. And later with be reset with the toggle. So I hope to turn it on with a toggle type switch and off with the momentary. I am very new to this and have several new books coming on electrical engineering.

 

[waross]

You may have more dependability if you use a momentary switch or button to reset. If the toggle is left in the wrong position uor circuit won't work.
yours