Author Topic: Low/Medum frequency royer induction heater  (Read 1367 times)

Offline kamelryttarn

  • High Voltage Technician
  • ***
  • Posts: 120
  • Karma: +0/-0
    • View Profile
Low/Medum frequency royer induction heater
« on: April 30, 2018, 12:49:26 PM »
I modified an ebay induction heater this weekend in order to try and heat up a small brass pipe. I tried to search the web for information about what frequency to use but I couldn't find much info so I tried a few different capacitor banks to see if I could measure the difference and take it from there.

Firstly I made a new work coil by winding a enameled wire about 1mm in diameter around a glass tube. With the default cap bank of 2uF I got about 70kHz without anything in the work coil and about 80kHz when I had the brass pipe inside it.

I used a lead acid car battery that was charged to around 13V for all tests. "Idle current" was 3,3A and "working current" was 11A so I assume the power transferred to the work piece is roughly 100W. This is probably not very accurate but all I wanted to do was figure out I should aim for a high or low frequency.

Next I soldered an additional 6pcs of capacitors to that backside of the PCB doubling the capacitance. When I fired it up I got 48kHz instead at idle and 60kHz with the brass pipe inside the work coil. Currents were 5A at idle and 19A when "working" so I think that brass responds better at lower frequencies.

The final test was made with a 30uF capacitor salvaged from the welder I bought to get my large three phase transformer. Unfortunately I did not get any current measurements but unloaded work coil gave me 19kHz . When I inserted the brass pipe and fired it up it quickly broke down and one of the mosfets started smoking.

The 30uF is probably not going to survive very long under these conditions but it was fun to give it a try. I will try and replace the mosfets and other components and do some more testing.
« Last Edit: April 30, 2018, 01:23:17 PM by kamelryttarn »

Offline Mads Barnkob

  • Administrator
  • High Voltage Expert
  • *****
  • Posts: 1236
  • Karma: +17/-0
  • Denmark
    • View Profile
    • Kaizer Power Electronics
Re: Low/Medum frequency royer induction heater
« Reply #1 on: May 01, 2018, 11:07:12 AM »
Great to see you back with more experiments :)

I think your test voltage is too low, you simply risk blowing the MOSFETs from not switching them fully on. Maybe try with 24V instead?

I seem to recall that the 23.9MB document here: http://kaizerpowerelectronics.dk/tools/file-archive/?drawer=application_notes*induction_heating contains some tables on frequency for different material types.
http://www.kaizerpowerelectronics.dk - Tesla coils, high voltage, pulse power, audio and general electronics

Offline kamelryttarn

  • High Voltage Technician
  • ***
  • Posts: 120
  • Karma: +0/-0
    • View Profile
Re: Low/Medum frequency royer induction heater
« Reply #2 on: May 01, 2018, 01:07:06 PM »
Great document! Did you scan that?

Yes I think you are correct about my driving voltage. However, since these are ridiculously power hungry circuits, finding a 24V psu that can drive this thing is not easy or cheap.

I found a really good online calculator that may aid me choosing a frequency: http://www.nessengr.com/technical-data/skin-depth/

I would like something like 1mm penetrating depth in my brass pipe which suggest an oscillating frequency just shy of 20kHz. I am also somewhat limited by my coil design since I only want to heat about 10-20mm of the pipe so I can not wind a 100mm long 15mm diameter coil to get a reasonable inductance of my work coil. One solution could perhaps be to wind a much larger diameter coil and up the psu voltage to compensate for the distance between the work coil and the work piece.

Offline petespaco

  • High Voltage Technician
  • ***
  • Posts: 135
  • Karma: +8/-0
    • View Profile
    • French Creek Valley Activities
Re: Low/Medum frequency royer induction heater
« Reply #3 on: May 01, 2018, 05:46:08 PM »
Quote
finding a 24V psu that can drive this thing is not easy or cheap.

Just add another 12 volt lead acid car battery.

Offline kamelryttarn

  • High Voltage Technician
  • ***
  • Posts: 120
  • Karma: +0/-0
    • View Profile
Re: Low/Medum frequency royer induction heater
« Reply #4 on: May 02, 2018, 08:55:59 AM »
Quote
finding a 24V psu that can drive this thing is not easy or cheap.

Just add another 12 volt lead acid car battery.

I would if I had one.

Offline petespaco

  • High Voltage Technician
  • ***
  • Posts: 135
  • Karma: +8/-0
    • View Profile
    • French Creek Valley Activities
Re: Low/Medum frequency royer induction heater/Battery
« Reply #5 on: May 02, 2018, 08:36:41 PM »
Getting a car battery:
  Many car batteries are replaced before they are totally shot.
Assuming that you do have a battery charger of some sort:
So, go to a car repair shop and ask if you can pick through their used batteries.  They get $5 or $10 in trade, right?  Prepare to pay that much.  If you tell them what you are doing with them, they may even sell them for less.
   Find one or two that still have some life left.  I know this is a rough "rule of thumb", but if the terminal voltage is above 12.2, it will probably take a charge, at least long enough for experimental purposes.

High Voltage Forum

Re: Low/Medum frequency royer induction heater/Battery
« Reply #5 on: May 02, 2018, 08:36:41 PM »

 


* Recent Topics and Posts

post Re: CT performance investigations (Pearson and DIY)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
T3sl4co1l
Today at 06:44:21 AM
post Re: Mazilli ZVS Driver Modification Problems
[Transformer (Ferrite Core)]
T3sl4co1l
Today at 06:37:47 AM
post Re: Mazilli ZVS Driver Modification Problems
[Transformer (Ferrite Core)]
Andrew321
Today at 02:22:09 AM
post Re: GM tube hv transformer
[Detection, Counting and Measurements]
haversin
Today at 01:15:21 AM
post Re: GM tube hv transformer
[Detection, Counting and Measurements]
klugesmith
January 24, 2020, 10:53:42 PM
post Re: WTB [EU]: Cellular Sector Antenna
[Sell / Buy / Trade]
Da_Stier
January 24, 2020, 10:52:48 PM
post Re: GM tube hv transformer
[Detection, Counting and Measurements]
haversin
January 24, 2020, 10:29:14 PM
post Re: Problems with my first DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
bozidar
January 24, 2020, 08:16:12 PM
post GM tube hv transformer
[Detection, Counting and Measurements]
AlexanderHun
January 24, 2020, 06:24:25 PM
post Re: DIY SMAW welder (stick welding)
[Electronic Circuits]
rikkitikkitavi
January 24, 2020, 05:17:01 PM
post Re: My 833A VTTC
[Vacuum Tube Tesla Coils (VTTC)]
MRMILSTAR
January 24, 2020, 04:37:25 PM
post Re: simple confusion about UD2.7c LEDs
[Dual Resonant Solid State Tesla coils (DRSSTC)]
justin66
January 24, 2020, 04:15:41 PM
post Re: My 833A VTTC
[Vacuum Tube Tesla Coils (VTTC)]
Mads Barnkob
January 24, 2020, 01:15:46 PM
post Re: simple confusion about UD2.7c LEDs
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
January 24, 2020, 01:10:38 PM
post Re: simple confusion about UD2.7c LEDs
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Hydron
January 24, 2020, 12:39:01 PM
post Re: simple confusion about UD2.7c LEDs
[Dual Resonant Solid State Tesla coils (DRSSTC)]
justin66
January 24, 2020, 11:43:08 AM
post Re: My 833A VTTC
[Vacuum Tube Tesla Coils (VTTC)]
kilovolt
January 24, 2020, 11:10:55 AM
post Re: DIY SMAW welder (stick welding)
[Electronic Circuits]
kamelryttarn
January 24, 2020, 10:11:51 AM
post Re: Doorknob vs Ceramic Disk
[Voltage Multipliers]
kilovolt
January 24, 2020, 09:03:52 AM
post Re: CT performance investigations (Pearson and DIY)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Hydron
January 23, 2020, 11:50:22 PM
post Re: simple confusion about UD2.7c LEDs
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
January 23, 2020, 11:42:56 PM
post Re: WTB [EU]: Cellular Sector Antenna
[Sell / Buy / Trade]
Mads Barnkob
January 23, 2020, 11:35:07 PM
post Re: simple confusion about UD2.7c LEDs
[Dual Resonant Solid State Tesla coils (DRSSTC)]
justin66
January 23, 2020, 11:15:12 PM
post Re: Doorknob vs Ceramic Disk
[Voltage Multipliers]
MRMILSTAR
January 23, 2020, 10:42:22 PM
post Re: CT performance investigations (Pearson and DIY)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
T3sl4co1l
January 23, 2020, 10:03:17 PM
post Re: Doorknob vs Ceramic Disk
[Voltage Multipliers]
kilovolt
January 23, 2020, 09:55:05 PM
post Re: Doorknob vs Ceramic Disk
[Voltage Multipliers]
MRMILSTAR
January 23, 2020, 08:39:10 PM
post Re: Universal bus precharge & fan speed controller
[Dual Resonant Solid State Tesla coils (DRSSTC)]
acobaugh
January 23, 2020, 08:37:43 PM
post Re: simple confusion about UD2.7c LEDs
[Dual Resonant Solid State Tesla coils (DRSSTC)]
acobaugh
January 23, 2020, 08:16:02 PM
post simple confusion about UD2.7c LEDs
[Dual Resonant Solid State Tesla coils (DRSSTC)]
justin66
January 23, 2020, 07:48:39 PM
post Re: Bipolar high voltage multiplier project - more than 70cm hot arc discharge
[Voltage Multipliers]
kilovolt
January 23, 2020, 05:07:46 PM
post Re: My 240kv voltage multiplier
[Voltage Multipliers]
kilovolt
January 23, 2020, 05:05:40 PM
post Re: Doorknob vs Ceramic Disk
[Voltage Multipliers]
kilovolt
January 23, 2020, 05:01:27 PM
post WTB [EU]: Cellular Sector Antenna
[Sell / Buy / Trade]
Da_Stier
January 23, 2020, 04:34:34 PM
post Re: My X-Ray Machine
[X-ray]
Agent Smith
January 23, 2020, 03:47:06 PM
post Re: DIY SMAW welder (stick welding)
[Electronic Circuits]
rikkitikkitavi
January 23, 2020, 02:24:07 PM
post Re: DIY SMAW welder (stick welding)
[Electronic Circuits]
kamelryttarn
January 23, 2020, 01:29:01 PM
post Re: DIY SMAW welder (stick welding)
[Electronic Circuits]
rikkitikkitavi
January 23, 2020, 12:45:40 PM
post Re: DIY SMAW welder (stick welding)
[Electronic Circuits]
kamelryttarn
January 23, 2020, 11:38:18 AM
post Re: DIY SMAW welder (stick welding)
[Electronic Circuits]
rikkitikkitavi
January 23, 2020, 10:43:36 AM
post DIY SMAW welder (stick welding)
[Electronic Circuits]
kamelryttarn
January 23, 2020, 08:32:56 AM
post Re: Doorknob vs Ceramic Disk
[Voltage Multipliers]
davekni
January 23, 2020, 06:06:20 AM
post Re: Mazilli ZVS Driver Modification Problems
[Transformer (Ferrite Core)]
davekni
January 23, 2020, 05:57:18 AM
post Doorknob vs Ceramic Disk
[Voltage Multipliers]
Andrew321
January 23, 2020, 03:57:09 AM
post Re: CT performance investigations (Pearson and DIY)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Hydron
January 23, 2020, 12:33:44 AM
post Re: CT performance investigations (Pearson and DIY)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
T3sl4co1l
January 22, 2020, 11:45:26 PM
post Re: CT performance investigations (Pearson and DIY)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Hydron
January 22, 2020, 11:30:26 PM
post Small DIY plasma globe using ZVS oscillator
[Transformer (Ferrite Core)]
davekni
January 22, 2020, 06:21:31 AM
post Re: Mazilli ZVS Driver Modification Problems
[Transformer (Ferrite Core)]
Andrew321
January 22, 2020, 05:54:17 AM
post Re: Mazilli ZVS Driver Modification Problems
[Transformer (Ferrite Core)]
Andrew321
January 22, 2020, 05:45:43 AM

Sitemap 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 
SimplePortal 2.3.6 © 2008-2014, SimplePortal