No Relay Required
JK Freak
Joined: Mar 2012
Posts: 572
Likes: 0
From: San Diego, CA
Accurate information regarding cost benefits allowing shorter high current / large gauge wire runs.
Need to correct the part about skin effect though. Skin effect applies only to higher frequency AC current. Current density across a wire carrying DC is unity. In other words the current through the core of the conductor is equal to the current flowing on the surface.
What is skin effect? - Definition from WhatIs.com
Another important property of relays (of the proper type) is the ballistic characteristics of the switching contacts. The speed of the make / break action of the contacts as well as the force exerted during break are engineered to minimize the possibility of contact erosion and welding. This is especially important when controlling heavy current, high inductance loads such as motors and compressors where arching will destroy a conventional switch quickly if thrown slowly by the operator. Even purely resistive loads such as lights will cause contact welding if the switching action is too slow. This property of a properly selected relay is frequently overlooked by circuit designers and is at least as important a design criteria as current capacity.
Phil
Need to correct the part about skin effect though. Skin effect applies only to higher frequency AC current. Current density across a wire carrying DC is unity. In other words the current through the core of the conductor is equal to the current flowing on the surface.
What is skin effect? - Definition from WhatIs.com
Another important property of relays (of the proper type) is the ballistic characteristics of the switching contacts. The speed of the make / break action of the contacts as well as the force exerted during break are engineered to minimize the possibility of contact erosion and welding. This is especially important when controlling heavy current, high inductance loads such as motors and compressors where arching will destroy a conventional switch quickly if thrown slowly by the operator. Even purely resistive loads such as lights will cause contact welding if the switching action is too slow. This property of a properly selected relay is frequently overlooked by circuit designers and is at least as important a design criteria as current capacity.
Phil
Didn't even think about switching time though, as i was thinking of smaller loads. Great point though, brother!
Thread Starter
JK Newbie
Joined: Oct 2011
Posts: 39
Likes: 0
From: Allen, Tx
Thanks to everyone that replied and provided input and ideas. There is a lot of food for thought here and I appreciate the assistance. Now I have to go manufacture a bracket to install the relay/fuse box and start my install. Of course like most that are still paying on their jeep I will start out small by installing some cube lights on the windshield and work my may up to a "MASTER JEEP" with winches, compressors, and other cool gadgets to waste my money on. My wife always shakes her head and tells me my jeep is my "barbie doll and doll house" all of those accessories.
JK Freak
Joined: Mar 2012
Posts: 572
Likes: 0
From: San Diego, CA
Thanks to everyone that replied and provided input and ideas. There is a lot of food for thought here and I appreciate the assistance. Now I have to go manufacture a bracket to install the relay/fuse box and start my install. Of course like most that are still paying on their jeep I will start out small by installing some cube lights on the windshield and work my may up to a "MASTER JEEP" with winches, compressors, and other cool gadgets to waste my money on. My wife always shakes her head and tells me my jeep is my "barbie doll and doll house" all of those accessories.
Anyway, good luck brother!
