On this page we will discuss the power electronics needed for our EDM machine. The basic mechanism of electrical discharge machining is a controlled spark between the electrode and the workpiece. This part of the electronic design generates the waveforms necessary to induce the spark. We will start by describing the fundamental mechanisms of EDM w
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hich dictate the voltage, current, and frequency needed, then show a very simple circuit satifying these requirements before describing its limitations and addressing these with an improved circuit. I spent some time in the library reading all the material on EDM that I could find. I will attempt to give a bibliographical reference for each essential fact I note below, to allow the curious reader to duplicate my research. Breakdown voltage from 60V [LAN], but 150V is inadequate to cause dielectric breakdown at. 001 -. 010 inch electrode spacings [DOR]. Doret added a 1500V "tickler" (low current, short duration) to trigger breakdown reliably up to. 010 inch. But he reports that the commerical machine made by Elox uses a 85V-90V peak-to-peak square wave to drive its electrode. Doret provided the following table of breakdown voltage versus voltage for Eloxol #13 dielectric (results not exactly reproducible, but are illustrative): Voltage across gap after breakdown is 10V-15V typical, independent of current. Gap resistance is usually around 1 ohm. "Arc voltage remains relatively constant as arc current is varied. " Short circuit between electrode and workpiece is indicated by voltage dropping to almost zero and current increasing sharply [DOR]. Most servo mechanisms use feedback based on average current through or voltage gap across the electrodes. But these mechanisms are just indirectly sensing the number (proportion) of open...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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