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Automotive relay

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mgb:

True, fire is possible with any electronics. But there's more going on going on with a furnace controller than just simply switching 12vdc   

mcseforsale:

I hacked a wall wart and created a 12V block inside my speaker panel.  3 of the connections are (+) 12V and 3 are (-).  I have the LEDs from my speakers, 12V amp, and my CCFL lights for my marquee powered there.  Here's the block:




I use a relay to switch on the wall wart at the AC level.  So, the hard drive power header trips the 12V DC side of the relay, then the relay switches 120V AC up into a second dual-gang box.  The relay was 9 bux.

http://forum.arcadecontrols.com/index.php/topic,117977.msg1267034.html#msg1267034

AJ



--- Quote from: kwijibo007 on August 19, 2012, 10:32:06 pm ---Hi, I've been slowly building my first Mame cab (cocktail) for about six months. I've been lurking here for a while and have picked up a lot of great tips. Firstly, big thanks to this great community!

I've tried searching but can't find a clear answer to whether or not I can use an automotive relay safely in my cab.

I purchased a cheap 12v amp to drive my speakers with the intention of powering them directly off the PC power supply. When I did this I got a lot of very bad feedback through the speakers. I did some searching and found this to be a fairly common issue with PC power supplies and amps.

Therefore I decided to use this relay http://www.jaycar.com.au/productView.asp?ID=SY4045&form=CAT2&SUBCATID=979#1 by using the 12v pc rail to control power coming from separate 12v power supply I'm using elsewhere in the cab. The point of this was that the amp would only power on when the PC was powered on.

Everything works great but after reading this thread http://forum.arcadecontrols.com/index.php/topic,109029.0.html I'm concerned that I might be doing something stupid by using the wrong kind of relay. This thread suggests using a solid state relay for the knocker being used. The knocker would be triggered many more times than my scenario but my relay will be active for many hours at a time...

I only know enough about electronics to cause trouble... Is what I have done ok? Is the PC power supply too large to control the realy? If the relay fails will it simply stop working I could it cause some damage to the pc/power supply/amp?

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Mysterioii:


--- Quote from: mgb on August 21, 2012, 12:03:55 pm ---True, fire is possible with any electronics. But there's more going on going on with a furnace controller than just simply switching 12vdc   

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Well, not gonna argue since I feel that we're pretty much on the same page, but the relay in question was just switching 24V (I had the schematic at the time, it might be printed on the inside door of the furnace, can't recall).  It wasn't anything particularly complicated.  What I personally feel happened was:


--- Quote ---1. Coil Layer Short

If overvoltage is applied to the coil, the coil's insulating film will be destroyed, and short-circuiting will cause high temperature. The color of the coil will change, and the resin around the coil will melt. It is also possible that an external surge was applied to the coil circuit, but this is often difficult to determine.
--- End quote ---

I don't feel that it was due to overvoltage, but in the dead of summer it was probably 120 degrees up in that attic.  Running constantly didn't help either.  Eventually the lacquer on the coil wire probably melted off a bit, shorted the coil, and burned it out.  Inside an arcade cabinet obviously the conditions are far less severe.

MTPPC:


--- Quote from: mgb on August 20, 2012, 12:06:02 am ---another simple way to do what you're trying to do is use a 12vdc plug in transformer / power supply for your amp and use a smart strip (i use the belkin smart strip and it works great) with your pc in the control outlet so anything you want on when your pc is on, will foolow the pc.

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I use the belkin smart strip in my pinball cabinet and the computer has a small draw making the strip undependable. If you go the smart strip route, be sure to buy the actual "Smart Strip" brand: http://www.amazon.com/Smart-Energy-Saving-Autoswitching-Technology/dp/B000P1QJXQ/ref=pd_bxgy_hi_img_b

It has an adjustment - the belkin does not.

mgb:


--- Quote from: MTPPC on August 21, 2012, 04:27:28 pm ---
--- Quote from: mgb on August 20, 2012, 12:06:02 am ---another simple way to do what you're trying to do is use a 12vdc plug in transformer / power supply for your amp and use a smart strip (i use the belkin smart strip and it works great) with your pc in the control outlet so anything you want on when your pc is on, will foolow the pc.

--- End quote ---
I use the belkin smart strip in my pinball cabinet and the computer has a small draw making the strip undependable. If you go the smart strip route, be sure to buy the actual "Smart Strip" brand: http://www.amazon.com/Smart-Energy-Saving-Autoswitching-Technology/dp/B000P1QJXQ/ref=pd_bxgy_hi_img_b

It has an adjustment - the belkin does not.

--- End quote ---

That's good to know, too bad they don't all have adjustment. My pc is a little older (p4) so it draws enough that all works well off the Belkin.

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