building a low voltage (1.2v), high current (1500A) rectifier

Thread Starter

bootlegengineer

Joined Dec 5, 2016
48
Hi! I'm trying to build a 1.2v 1500a rectifier in order to power an electrolysis machine, but i only have mosfets, transistors, diodes, and bridge rectifier ICs rated for 400v, 23a continuous. my question is would I be able to create several rectifiers and bunch them together (example picture shown below) in order to achieve this without the whole thing melting?


bdg ractifier.png
 

kubeek

Joined Sep 20, 2005
5,732
That sounds like a really lousy solution. At that sort of power you should be much better off using mosfets and synchronous rectification. Also, where do you plan to get a ~1.5V 1500A transformer?

Also, what is that CAP supposed to mean?
 

Thread Starter

bootlegengineer

Joined Dec 5, 2016
48
That sounds like a really lousy solution. At that sort of power you should be much better off using mosfets and synchronous rectification. Also, where do you plan to get a ~1.5V 1500A transformer?

Also, what is that CAP supposed to mean?
Yea I know the design is lousy, but I'm not 100% sure how to build a synchronous rectifier and any attampts to research it didn't yield and good results on google.

Also, the transformer is a modified 240v welder transformer and the "CAP" stands for capacitor.
 

kubeek

Joined Sep 20, 2005
5,732
At 1500A you will be wasting roughly 3kW in heat. That is like two or three space heaters, plus you will have a huge hedache beacuse the recitifers will not share the current equally, and you will most likely end up with thermal runaway and a ton of destroyed parts.
Suggest you start small with 50 or 100A and go from there. Or even better divide the electrolysis plates into smaller sections and power them separately. 15 100A diodes, each powering its own 100A circuit will be a lot easier than one huge parallel mess.
And forget about the capacitor, you would need a capacitor bank the size of a washing machine to get any sort of filtering.
 

Thread Starter

bootlegengineer

Joined Dec 5, 2016
48
At 1500A you will be wasting roughly 3kW in heat. That is like two or three space heaters, plus you will have a huge hedache beacuse the recitifers will not share the current equally, and you will most likely end up with thermal runaway and a ton of destroyed parts.
Suggest you start small with 50 or 100A and go from there. Or even better divide the electrolysis plates into smaller sections and power them separately. 15 100A diodes, each powering its own 100A circuit will be a lot easier than one huge parallel mess.
And forget about the capacitor, you would need a capacitor bank the size of a washing machine to get any sort of filtering.
Yea very true, but my whole predicament is that my components are all rated for 400v 23a. Also, the design of my plate assembly only includes 1 positive and 1 negative plate and the rest in between are neutral.
 

Thread Starter

bootlegengineer

Joined Dec 5, 2016
48
At 1500A you will be wasting roughly 3kW in heat. That is like two or three space heaters, plus you will have a huge hedache beacuse the recitifers will not share the current equally, and you will most likely end up with thermal runaway and a ton of destroyed parts.
Suggest you start small with 50 or 100A and go from there. Or even better divide the electrolysis plates into smaller sections and power them separately. 15 100A diodes, each powering its own 100A circuit will be a lot easier than one huge parallel mess.
And forget about the capacitor, you would need a capacitor bank the size of a washing machine to get any sort of filtering.
Also, my power supply is only 1.8kW. Im using a 120v 15a power supply
 

kubeek

Joined Sep 20, 2005
5,732
If you reconfigured your transformer to be center-tapped, then you would be able to get roughly 700A before blowing the breaker, with the remainig power being wasted on the diodes.
 

Externet

Joined Nov 29, 2005
1,537
Why/what would melt? It will take more than your box full of bridge rectifiers... Nice secondaries can be instead wound on the cores of three phase transformers with flattened copper tubing... Three single 2000 Ampere diodes are available



4KW transformers are available too, as your 1.8KW one does not make it...


Or,
----> http://goldmachinery.com/machinery/silver-refining-electrolysis.htm

----> https://www.911metallurgist.com/zinc-electrolysis/

----> http://www.controlledpwr.com/brochureFiles/59/series30_brochure.pdf

----> https://platingmachines.com/item/electroplating-power-supply/

----> https://tucheng.en.made-in-china.com/product/RCmxFzcKnkVM/China-Low-Price-Hot-Selling-500A-1000A-2000A-IGBT-Rectifier-for-Electroplating-24-Hours-Continuous-Running.html

----> https://www.indiamart.com/proddetail/anodizing-igbt-rectifier-14677212497.html
 

Thread Starter

bootlegengineer

Joined Dec 5, 2016
48
@kubeek: Thats fine. All im trying to do is get enough power to get the psi level of the oxygen and hydrogen coming out of the tube high enough so that the fire coming out of the end doesnt extinguish itself. Im building an oxy-hydrogen welder. If 700a is all I'll get, then ill just raise the voltage and drop the current.
 

Thread Starter

bootlegengineer

Joined Dec 5, 2016
48
Why/what would melt? It will take more than your box full of bridge rectifiers... Nice secondaries can be instead wound on the cores of three phase transformers with flattened copper tubing... Three single 2000 Ampere diodes are available



4KW transformers are available too, as your 1.8KW one does not make it...


Or,
----> http://goldmachinery.com/machinery/silver-refining-electrolysis.htm

----> https://www.911metallurgist.com/zinc-electrolysis/

----> http://www.controlledpwr.com/brochureFiles/59/series30_brochure.pdf

----> https://platingmachines.com/item/electroplating-power-supply/

----> https://tucheng.en.made-in-china.com/product/RCmxFzcKnkVM/China-Low-Price-Hot-Selling-500A-1000A-2000A-IGBT-Rectifier-for-Electroplating-24-Hours-Continuous-Running.html

----> https://www.indiamart.com/proddetail/anodizing-igbt-rectifier-14677212497.html
The rectifiers would melt because of the insanely high current. The transformer isn't a big deal.
 
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