The Heart of an Induction Heater

Heart of an Induction Heater
Hello everyone! I started this morning out with a beautiful walk along the gulf coast for the American Heart Association. I wanted to share two things with you today, a couple photos from the event and one more thing (keep reading).
Gulf Coast Heart Walk American Heart Association American Heart Association Heart Walk American Heart Association

Generosity Begets Generosity

All the giving got me thinking, after all, you know what they say about giving. Generosity Begets Generosity. Generosity is a gift that keeps on giving—so many of the gifts we receive in life turn us into givers.
I wanted to show my appreciation to the Patrons who continue to believe in this project even when life slows its progress way more than I’d like! I was reminded today that I actually did not start this project for myself. I am not a blacksmith, I have no immediate need for an induction heater, but I am a creator. Each and every human has this incredible capacity to imagine and to change things. I wanted to bring a tool within the reach of others that remained out of reach for most. Not a wimpy, “doesn’t deliver on what the box said kind of tool”, but one of a caliber that is not matched in the consumer market at all today.

The Heart of an Induction Heater

I would like to offer the “heart of an induction heater” to all of my existing Patrons (as of today September 22, 2018).
U-I Core Set
E/I Core from two U/I cores
U-I Core Set
At about twice the size of a human heart and just about as difficult to source, the matching transformer is by far the most critical, specialized component of the induction heater. Coolant flows around its core in two directions keeping it cool as huge amounts of energy flow through it, making it possible to pump power from your wall outlet into your workpiece. Without it, the IH is just an inverter with some other not really all that exciting electronics. It would be akin to a truck without a transmission. You can’t just connect the crankshaft to the wheels and expect anything good!
I’m including two massive U & I core sets. The same ones that make up the large E/I matching transformer in the newest revision.
Material: 3C85
  • Single U-I core set AL: ~8400
  • Single U-I core set µe: ~2000
  • Single U-Core Dimensions: 93mm x 76mm x  30mm thick
  • Single I-Core Dimensions: 93mm x 28mm x 30mm thick
  • Overall Dimensions: U-I Set: 104mm x 93mm
  • Opening Dimensions: 47mm x 36mm
3C85 Material Technical Data:
  • Optimal frequency: < 200kHz
  • Permeability ui:           2000 +/- 20%
  • Induction at 100kHz, 250 A/m, Bs:   > 400mT
Heart of an Induction Heater

But Wait There’s More

Since driving your IGBT properly is a big deal and kind of important for the whole setup, I’m also including a new driver PCB with two Powerex VLA504-01 Hybrid IC Gate Drivers and two Powerex VLA106-15242 DC to DC Converters. Just those four components are about a $70 value alone if you buy them from Digi-Key. The remaining components on the board are just a few dollars worth of passives. The full schematics and bill of materials for the Hybrid Driver board can be found here: https://github.com/ThingEngineer/ReactorForge/blob/master/hardware/Hybrid%20Driver/BOM.txt
Recap, what I’m giving my Patrons:
  • 2 x 93mm x 76mm x  30mm 3C85 Ferrite U Cores
  • 2 x 93mm x 28mm x 30mm 3C85 Ferrite I Cores
  • 2 x Powerex VLA504-01 Hybrid IC Gate Drivers
  • 2 x Powerex VLA106-15242 DC to DC Converters
  • 1 x New Hybrid Driver PCB

Send Me Free Stuff!

If you are currently a Patron as of the date of this post and would like me to send you this thank you gift, just send me a private message on Patron saying hello and include your shipping address. The only thing I would ask is that you only request this gift if you are going to use it. We’ll go on the honor system here.
I look forward to working on this project more and hearing your and feedback as well, as you either work on your own or use an IH I’ve built for you in the future.
Thank you!!!
Q: Is it possible to drive a tank circuit in an Induction Heater with one IGBT?
A: Yes.  This is actually how my brothers old IH is set up now. Here is a quick schematic. The capacitors were all off eBay for cheap.
Single IGBT Inverter
Matching transformer and coupling caps
Single IGBT Inverter
Filter Cap & Coupling Caps
Single IGBT Inverter
Single IGBT driver and brick
Single IGBT Inverter Schematic
Single IGBT inverter schematic
Q: Can you share more details on the matching transformer?
A: Of course but I need some more space to do it properly. I’m working on a post about just that. In the meantime here is a photo and a short explanation to give you something to start with.
  • The Matching transformer is wound with 1/4″OD inch copper tubing.
  • All windings are wrapped in x2 overlapping Scotch Professional Grade Vinyl Electrical Tape Super 88. Meaning as you spiral down the length of the copper tube the electrical tape covers 50% of the layer before it resulting in a 50%+50% overlap (no gaps) and a 200% layer thickness overall (better electrical and mechanical isolation).
  • The primary winding (connected to the inverter) is composed of 13-14 turns. It has terminals made of copper soldered near the ends to accommodate a high current connection while leaving the ends of the tube free to hook up to the cooling system.
  • The secondary winding (connected to the tank cap and work coil) is a single turn composed of 4 individual 1/4″ copper tubes connected on each end with a 1/2″ manifold. One side of the manifold connects to one side of the tank capacitor, the other connects to one side of the work coil via a copper plate. The other side of the work coil connects back to the other side of the tank capacitor via another copper plate in close proximity to the first plate. This whole set up ensure the flux is fully enclosed in the system. Were it not you would heat up surrounding metal and loose usable power. (An issue in the first model with the toroidal matching transformer and large tank setup.)
Matching Transformer
Q: If I’m not a Patron could I just purchase one or some of these items from you?
A: I’m not set up to do this formally yet but I can accept Paypal and work something out. I’m also still working on a bulk order for the passives to get the entire driver kit complete. The price difference with and without the passives will likely be less than a couple bucks, keep that in mind if ordering those parts would be an issue for you.
Q: What about the other parts of the system like the main board, AC rectification & filtering, liquid cooling setup, etc. Can I get one of those?
A: Although I do have fairly complete designs worked out on the rest of the system I don’t have a stock on the parts. I am going to start making posts on the individual components starting with the matching transformer to give you what you need to duplicate each part. The main board schematic and board design are on GitHub although I will be making some changes to it on the next go around.

Patreon Charges and 260 Pound Parts Delivery for IH Kit

Patreon Charges

There has been a lot of confusion created by they way Patreon charges its patrons and paying creators. You can find the official information can here: https://patreon.zendesk.com/hc/en-us/articles/115005631963 And here is another excellent article on the topic by TechCrunch.

TLDR; The short version is, Patreon moved its credit card processing service fees from the creator to the patron. Because of this change, Patreon was able to lower the overall fee amount and give more to the creator. The fee amount is (2.9% + $0.35) for each monthly pledge.

Because I have worked on unique e-commerce projects, I understand the intricacies and complications of bulk credit card processing, multiple payees, and the associated charges and chargeback liabilities. However, I do not support Patreon’s decision, and I firmly believe there is a better solution. Because Patreon is a goodwill engine, I think this move is, for lack of better terms, just weird. In addition, I won’t personally be canceling any of my Patreon pledges. Nevertheless, as a patron myself and now a fledgling creator, I do hope that we see these processing fees moved back to the creator.

Other Support Options

Your support is much appreciated, but entirely voluntary. You may continue to make a small donation to support the project and website using Patreon. If you decide to cancel out of principal, I understand entirely. If you prefer I’ve added a PayPal button on the pledge page “Coffee” to enable you to make a small reoccurring monthly pledge that you can change or cancel it at any time.


Support the ReactorForge via PayPal



Or you can send a one-time pledge. Please include a note to let me know it’s a gift and what made you decide to support ReactorForge!




I may add members only functionality to the website linked to Patreon PayPal as well, to mirror and even enhance the capabilities Patreon offers. But I’m not sure there is indeed a need for that yet, or possibly ever. Thank you all again for your support, be it monetary, intellectual, or constructive criticism. I value all of it!

ReactorForge Parts Delivery

I just received the first shipment of parts for building more ReactorForge induction heaters, 258 pounds worth. This component is of one particular importance and one I have settled on despite other possible changes I will be making to the design. Anyone care to take a guess what part this is?

ReactorForge Induction Heater Parts Shipment ReactorForge Induction Heater Parts Shipment

Induction Heater Price what is your target range?

Induction Heater Price

I want to get a better idea of what a machine like this is really worth to you. I’m doing this in an effort to ensure that the additional work I’m about to put into this project to transform isn’t in vain. Because an induction heater price can vary wildly and to go from DIY induction heater to a kit or production unit is a big leap.

I will be completing this project and making it open source regardless of whether or not making a kit is viable. But before I do go down that path, to kit or not to kit, I’d like to know what it’s true value is.

To give you something more concrete to evaluate use the two videos below to get a rough idea of the capabilities of the machine as it relates your needs and use these technical specs.

Reactor Forge Induction Heater Specs:

  • Simple interface and usability
  • Operating Voltage: ~220V
  • Maximum Current Draw: ~40A
  • Typical Current Draw: 10-30A
  • Power Factor of near .99% (You won’t find that in a cheap overseas model!)
  • 100% duty cycle
  • Water cooled (cooler not included but it can be as simple as a garden hose attachment)
  • Mid-range frequency operation best for small to medium size workpieces. (Lower frequency is possible for larger items above 5-6″ cross section at lower power levels.)
  • Remote foot switch operation
  • Simple to complex programmable cycles
  • Many safety features
  • All digital operation (so performance is not affected by the environment)
  • A fully sealed case for protection against debris and dirty shop air.
  • Hackable! Many future improvements possible such as workpiece temperature feedback for reaching very precise temperatures.

Videos of the current Reactor Forge, Critical Mass in use:

https://youtu.be/C8s0zIcqVfk

https://youtu.be/4vICz4akL6k

So what is your target induction heater price?

Please check out the full post and Poll on Patreon to cast your vote: https://www.patreon.com/posts/15375592

Induction Heater Price

Also, check out The ReactorForge Origin Story to learn more about how this project got started.

Why a Patreon page

Patreon

This project is moving forward regardless of Patreon backing. However, any support will be a great motivator as well as help with the time, money and effort required for this project.

The ReactorForge open source induction heater is my way of giving back to the maker community so Patreon or not I hope you find use in this work! For anyone who has ever wanted to make a homemade induction heater that goes beyond being just a novelty, the DIY kit and plans will be your ticket!

Support ReactorForge on Patreon

Patreon