HELP with Schematics for magnet launcher - Page 1
Forum section: electronics / projects

author: CLD
author_rank: Newbie
timestamp: July 09, 2019, 09:59:16 pm
content: I am recreating the induction launcher in this YouTube vid:I have all of the parts:2 tranformers4 resistorsbridge rectifier4 capacitorsSCRSwitchElectromagnet coilI don't know how to read the schematics - HOW do I connect all of the parts and where for each?Get back to me so we can talk about it.Thanks

author: alsetalokin4017
author_rank: Super Contributor
timestamp: July 10, 2019, 09:52:53 am
content: I suppose it really won't do any good for me to tell you that this project can be _deadly_ and from your questions is probably not a good project to start out your electronics journey with.The capacitors store enough energy to kill you several times over, not to mention other hazards like bits of metal spalling off and hitting you in the eyeballs, or other spectacular failure modes if you do something wrong, or even if you do it all right! Believe me, you do not want to be in the room when a 4700 uF electrolytic capacitor charged to 600 volts blows up from being reverse-volted.And while a college lab might be able to get away with an open layout like that for a mains-connected voltage doubler capacitor discharge circuit... a hobbyist who does not yet know how to read a schematic probably should not even consider doing things like this.All that being said, this is a fun project and I can understand why you want to do it. But how to approach it? It is a straightforward and simple circuit but there may be some problems.First, you say you have a "bridge rectifier" and the video says they used a three-phase bridge rectifier module. But the schematic only indicates that half of a singlephase FWB is used (just two diodes.) So the first thing we need to find out is whether or not your actual bridge rectifier can be used as the schematic indicates, and I can't tell from the info provided.Other than that, it is largely just a matter of putting wires together as the schematic indicates. The lines indicate wires, dots indicate connections, the black dots on the transformer symbols indicate the "start" of the windings, the + and - symbols indicate anode (triangle) and cathode (bar) of the diode symbols. But you should think seriously about the layout and safety. Your layout absolutely must protect the terminals of the capacitors and all wiring from possible shorts or inadvertent contact with living things. Your wiring has to be sturdy, well insulated, the leads from the caps and SCR to the launch coil should be heavy and short, the connection to the mains should be fused or protected with circuit breaker (you could use a good quality power strip with breaker) and you should NOT operate or test this thing while alone. Have somebody there to put out the fire and call the ambulance. And I am only half kidding.In case it didn't sink in the first time, this project can KILL YOU DEAD. No mistakes allowed. Imagine that HDD platter embedded in your forehead.

author: alsetalokin4017
author_rank: Super Contributor
timestamp: July 10, 2019, 09:59:45 am
content: OK, now let's consider your transformers. There are many different kinds of transformers! Please tell us the part numbers and any other information you may have for your transformers. The ones in the project are 1:1 isolation transformers with a single secondary winding. That means there are only two wires on the output side of the ones in the video. But yours have 4 wires. Fortunately they are color-coded. So we need to know the details of your transformers so we can figure out how/whether they can be used in your project.ETA: Your proposed connection diagram for your transformers (your 4th picture above) is certainly wrong because the original schematic shows the secondaries of the two transformers connected in series, and it appears to me that your diagram has all secondaries connected in parallel. So please don't do anything more until we can get the transformer questions sorted.Do you own or have access to a Digital MultiMeter (DMM)?

author: Richard Crowley
author_rank: Super Contributor
timestamp: July 16, 2019, 01:50:42 am
content: There is NO evidence in your photos and drawings that ANY of those components are appropriate for your circuit.Starting with (and ESPECIALLY) the mystery transformers.The original video had almost NO useful information about component ratings.The video did not contain sufficient information for an expert to reproduce the circuit.Much less someone who seems to have little or no working knowledge of electronic components.This looks like a disaster just waiting to be wired up.

author: Brumby
author_rank: Unknown
timestamp: July 16, 2019, 11:29:23 am
content: I will affirm what others have said:1. You do not seem to have the required knowledge to build this project SAFELY2. The energy levels involved are seriously scary - and LETHAL3. NONE of the components you have shown can be confirmed as being appropriate4. The transformer wiring you have suggested is no better than random and is certainly wrong5. Suitable capacitors will NOT be cheap and will not be found commonly - and any capacitor you use that isnotsuitable or is wired incorrectly could become a hand grenade. No, I am not joking.If you really want to build this project, my advice is simple: You MUST get someone to be at your side to help you who knows about component selection and how to work with the voltages and energies involved.Yes, this is a cool project and we would encourage you to explore - but we must emphasise that safety must be yourfirstconsideration.

author: NiHaoMike
author_rank: Super Contributor
timestamp: July 16, 2019, 04:16:03 pm
content: In physics class, it's common to have an electromagnetic launcher demo that's just a coil connected to the mains. Not beginner friendly but at least it's perfectly safe when unplugged.