Electromechanical Project: Induction Heater

Norppu

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This thread contains instructions and drawings to create an induction heater.

BlockDiagram.jpg

The internet is bloated with diverse projects for induction heater but unfortunately only a few of them have any chances to become an useful tool and most of them will fry out in a matter of days or even seconds With this design I harness my very long experience on electronics and try to cope with the machining. Yes, this project involves quite some interesting machining including (but not limited to) piping fittings for the heater coil and radiator, water cooled heatsinks for rectifier, FET array and controller power electronics.

At the business end of the induction heater there is a ZVS driver. I chose a chinese 1800W driver which I will modify to be able to fully deliver the power to the output coil. At the moment the coil connections are flimsy and the supplied coil is a joke. However, one cannot buy the separate components with the price of this unit. Cheap Chinese units are available on all common auction sites.

IMG_5046.jpg

The coolant will be circulated with a pump. When choosing a pump for a project like this one should look for a device with an adequate yield. A centrifugal pump is generally adequate but those must be placed under water level as they have no suction. I chose a ROTEK 24V WPCD 11.5l/min@0.3 bar device. Although this pump is submersible it will be running outside the water reservoir.

IMG_5049.jpg

The generated heat must be dissipated out of the cabin. For this task I chose a 115 x 210 mm Mocal oil cooler with BSP fitting. Thank god those fittings are not tapered. It will still be a challenge for me to machine those fittings. Luckily those must be made of aluminium.

IMG_5051.jpgIMG_5052.jpg

The coolant flow and temperature must be monitored. For flow monitorin a flow meter is used. This is a device (YF-S402) that sends pulses when the fluid is flowing. For temperature monitoring two Philips KTY-sensors are used. One for coolant and another for cabin ambient temperature. Those are very cheap and more than accurate enough for the task. In the picture I have disassembled the flow sensor. This unit should not be placed on the pressure side of the coolant flow. Best place is right before or after the radiator.

IMG_5086.jpg

The blower (fan) will be one or more PWM controlled PC cabin blowers. For this project I chose a super-silent blower that has the PWM control and RPM monitoring facilities. Most of the blowers (4-pin PWM connector) have these features inbuilt.

Blower.jpg

All this needs a controller. I have designed one and the schematics, etching masks, gerber files for PCB manufacturers and whatnot are included in the attached eagle.zip. With these files it is possible either manufacture the PCB home or let some PCB prototype-manufacturer take care of that. The chosen components are widely available either directly or be easily replaced.

UiMockup.jpg

The controller needs a program. The microcontroller is a cheap Atmel AtMega32L which has just enough I/O for this task. I will attach the program (written with avr-gcc) once I get it debugged.

There will also be an User Manual in English, German, Swedish and Finnish languages.

In case You want to see all files involved with this project these are available at Hobby-Machinist Directory in my server.
 

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  • eagle.zip
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Welcome to Hobby-Machinist.
Very impressive second post.
I don't have the nerve (to much common sense) to open your .zip file yet but I will watch this thread and hope it turns out as well as it has started.
 
Welcome to Hobby-Machinist.
Very impressive second post.
I don't have the nerve (to much common sense) to open your .zip file yet but I will watch this thread and hope it turns out as well as it has started.

Thanks !

You can look the individual files in my server. The zip file is here just to conform with forum rules. In case You are interested in microcontroller programming or electronics designs then it might be worth to look at.

The zip contains the PCB design for this project. I have already ordered five of those from a Chinese PCB manufacturer. As always those will contain at least 10 bugs but one has to start somewhere.

I will also add more plans for the water cooled heatsinks, common layout in the cabin and of course the Atmel code. The unfinished code is already there in the directory to see. Link to that directory in in the post.
 
Hello, what do the letters ZVS stand for?
edit: found it : zero voltage switching
Mark
 
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Holy Crap! @Norppu, what a great thread!
....and you just joined....

Welcome to the Hobby-Machinist!

I am watching this thread.
Thanks for sharing your expertise.

-brino
 
This unit should not be placed on the pressure side of the coolant flow. Best place is right before or after the radiator.

why?
thanks
-brino
 
why?
thanks
-brino
Two reasons.
The plastic case of the flow sensor is not trustworthy. It will most probably generate a leak after being 5 years in use and having a pressure. I will have this apparatus placed in a manner that if (when) it leaks, the leak will go into the reservoir.

Another place for the flow meter would be between the pump and the reservoir. However, it is a bad idea to have flow restrictions in the suction side of an centrifugal pump as that may create cavitation and premature failure of the pump impeller.
 
I don't have the nerve (to much common sense) to open your .zip file yet but I will watch this thread and hope it turns out as well as it has started.

Great computer hygiene!

I have download the file and then uploaded it to VirusTotal.
They test the file with 61 different virus and malware detection tools and it came out fine.
Here is the link to the results:
https://www.virustotal.com/en/file/...a6eb82bc7eaed0741feb8979/analysis/1529165825/

The file also tests clean with my locally installed tools.

-brino
 
Wow, Norppu awesome thread and welcome to HM! Members like you are what makes this site great.
I bought one of those Chinese induction heaters and found it to be pretty much useless. I will put your design on my project list.
 
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