Industrial Application
Printed From: the12volt.com
Forum Name: General Discussion
Forum Discription: General Mobile Electronics Questions and Answers
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=50096
Printed Date: May 12, 2024 at 2:55 PM
Topic: Industrial Application
Posted By: mhouse
Subject: Industrial Application
Date Posted: February 14, 2005 at 5:44 PM
I am trying to figure out how to use a relay in an power systems application for emergency power down. Lets say that I have a 120V 20 A load. I take a emergeny switch and connect it to a SPST relay so that when I hit this switch(lets say it is a normallyl open switch) it caused the load to loose power. See if the magnetic coil is getting power and it needs it to keep the switch closed it would seem to me that you cannot use a NO emergency switch unless maybe you use a relay that is NC and then when I hit my switch it caused the loop to the magnetic coil to enegize forcing the switch open but then I have lost all DC power when was generating the DC power that most coils need in a relay. Any input is welcomed. Marcus ------------- Mhouse
Replies:
Posted By: KarTuneMan
Date Posted: February 14, 2005 at 6:33 PM
Uhmm......ya....that sounds....uhm, good  -------------
Posted By: overworked
Date Posted: February 16, 2005 at 12:17 AM
um......wanna try agin for us?....cant input what we dont understand
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Posted By: shoelesscraig
Date Posted: February 18, 2005 at 11:44 PM
Didn't catch a word of that
Posted By: flynntech
Date Posted: February 20, 2005 at 4:13 PM
call an electrician.
Posted By: the1alchemist
Date Posted: February 21, 2005 at 8:40 AM
I THINK I got SOME of it...
First of all,there are relays with 120v coils,
assuming you have found one,I would suggest a normally open switch,just like in the car,you wouldn't want a relay energized all the time..
another prerequisite of the relay would be,to have a contact rating above your load(or at least the constant load rating equal to,and an inrush rating at least double(depending on capacitance issues with the load,like a huge motor,whatever,they should rate the equipment on a plaque somewhere))
just put the relay's com-NC in series with the current(assuming 120v,not 220..a 220 motor would need 2 relays if it is grounded)
then put your coil in series with your normally open switch,so....
when you hit the switch,the com/NC is now com-NO..no current flows...
as the others on the forum have already made clear,your request was very cryptic..so I hope this helps..there is always a solution...
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'Stereo' Mike
The Audio CARtist,LLC
9600 Balt. Ave.
College Park,MD 20740
301-474-6260
Posted By: mhouse
Date Posted: February 22, 2005 at 8:09 AM
This was helpful. Thanks.  ------------- Mhouse
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