Rearranged and solve for distance (d) in meters at which air ignites at a voltage of 220Vac : Voltage (V) ionization of air = 1,000,000 V/per meter (The voltage at which air spontaneously ignites) The problem here is that if you run a simulation program that simulates the physical erosion of the metal, at some point in the simulation the metal in the CLOSED position is NOT making good contact but is SO CLOSE to making contact that the electrons can jump across the gap based on the equation: When it fails, it fails because it is eroded and the metal is no longer making a good contact. If there are 365 days in a year and you switch the light 3 times a day, and the relay is rated for 3000 cycles, it would last 2.7 years. There are MANY DC SSRs as well, and there are also 120vac AC SSRs so there are about ten ways to screw up when ordering an SSR online.Ī relay switching 220vac maybe several thousand cycles. Personally, my choice would be a solid state relay because there is no arcing because it has a zero -crossing detector inside and only switches states at the ac waveform zero crossing point.Īlso, whenever buying SSRs on ebay, ALWAYS LOOK AT THE SPECS ! The arcing can be supressed using a "snubber" circuit but it probably isn't necessary for just a light. The relays are rated for "n" number of cycles and I have been told that it is safe to ignore the arc because it is harmless and the only effect is that is erodes the contacts gradually over time requiring the replacement of the relay after some number of thousand cycles. If you operate the relay with a non-light generating load in a dark room you will see the flash inside the blue plastic case of the relay. This is what will occur inside the relay every time you turn the light OFF, but NOT when you turn it ON. You will see a flash as you unplug the device. The arc which occurs across the gap as the contacts separates is actually plasma. Electricity travels at 1/100the the speed of light so it is plenty fast enough. At the moment that the plug begins to leave the outlet, the electrons will jump across the gap as the contact separates from the blade in the outlet. Put your hand about 10" AWAY from the plug and pull the cord and plug from the outlet in the dark WHILE the load is switched on and under current (like a motor or fan or any thing but a light). Turn OFF all the lights in the room so it is dark. The catch is you can't use a lamp or light for the load because you need to have the load ON in a dark room. You can verify this for yourself without any lab equipment. (That means turning the device OFF, as opposed to turning it ON.)
It is not a good practice because there will ALWAYS be some degree of arcing when switching ANY AC LOAD UNDER POWER. Using a physical contact relay to switch HVAC is not a good practice but by itself does not constitute a safety violation. The LINE from the facilities power (wall) goes to the COM and the Line from the Light (LOAD) goes to the N.O. The Neutral wire goes DIRECTLY to the white neutral wire of your light. The Neutral is NEVER SWITCHED ! (Don't do it ). The Line and Neutral which carry 220 volts
Arduino relay shield 230v install#
You install your arduino in a metal box then the green ground wire should be terminated on a screw attached to your box to meet electrical code standards for safety. (metal box) is connected to so if you have a loose wire and you touch the box you won't die. The ground is supposed to be the point YOUR chassis The ground is not related to the control of devices. Not unless you want to blow the fuse (or trip the breaker) for the 220vac and vaporize the wire all in one shot.
Would it be LiveNO, Neutral and GroundCOM? It's not just Gnd and live it's Live, Neutral and Gnd.
0 kommentar(er)
