Author Topic: Low/Medum frequency royer induction heater  (Read 1759 times)

Offline kamelryttarn

  • High Voltage Technician
  • ***
  • Posts: 125
  • 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: 1456
  • Karma: +24/-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
https://www.youtube.com/KaizerPowerElectronicsDk60/join - Please consider supporting the forum, websites and youtube channel!

Offline kamelryttarn

  • High Voltage Technician
  • ***
  • Posts: 125
  • 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: 159
  • Karma: +9/-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: 125
  • 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: 159
  • Karma: +9/-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: Dual MOT tesla coil
[Spark Gap Tesla Coils (SGTC)]
davekni
August 05, 2020, 11:48:55 PM
post Re: How much is the voltage used in Corona Discharge tubes for ozone Generation?
[Transformer (Ferrite Core)]
davekni
August 05, 2020, 11:37:13 PM
post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
AstRii
August 05, 2020, 08:01:11 PM
post Re: Fun with wireless power
[Solid State Tesla Coils (SSTC)]
Lightning On Demand
August 05, 2020, 06:34:08 PM
post Re: How much is the voltage used in Corona Discharge tubes for ozone Generation?
[Transformer (Ferrite Core)]
Uspring
August 05, 2020, 12:56:32 PM
post Re: Fun with wireless power
[Solid State Tesla Coils (SSTC)]
Mads Barnkob
August 05, 2020, 12:55:52 PM
post Re: Bipolar high voltage multiplier project - more than 70cm hot arc discharge
[Voltage Multipliers]
Teravolt
August 04, 2020, 09:21:09 PM
post Re: How much is the voltage used in Corona Discharge tubes for ozone Generation?
[Transformer (Ferrite Core)]
johnf
August 04, 2020, 09:16:55 PM
post Re: Does anyone know how this site works.
[General Chat]
thedoc298
August 04, 2020, 05:53:03 PM
post Re: Does anyone know how this site works.
[General Chat]
thedoc298
August 04, 2020, 05:51:03 PM
post Re: Fun with wireless power
[Solid State Tesla Coils (SSTC)]
Lightning On Demand
August 04, 2020, 05:17:26 PM
post Re: Fun with wireless power
[Solid State Tesla Coils (SSTC)]
Max
August 04, 2020, 02:14:56 PM
post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Max
August 04, 2020, 02:08:07 PM
post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
futurist
August 04, 2020, 10:48:35 AM
post Re: How much is the voltage used in Corona Discharge tubes for ozone Generation?
[Transformer (Ferrite Core)]
UB_Serpent
August 04, 2020, 10:02:39 AM
post Re: Dual MOT tesla coil
[Spark Gap Tesla Coils (SGTC)]
Jun
August 04, 2020, 08:47:07 AM
post Re: Dual MOT tesla coil
[Spark Gap Tesla Coils (SGTC)]
Jun
August 04, 2020, 08:43:00 AM
post Re: Does anyone know how this site works.
[General Chat]
Mads Barnkob
August 04, 2020, 08:33:47 AM
post Re: Does anyone know how this site works.
[General Chat]
MRMILSTAR
August 04, 2020, 05:09:26 AM
post Does anyone know how this site works.
[General Chat]
thedoc298
August 04, 2020, 01:54:49 AM
post Fun with wireless power
[Solid State Tesla Coils (SSTC)]
Lightning On Demand
August 03, 2020, 11:55:41 PM
post Re: Dual MOT tesla coil
[Spark Gap Tesla Coils (SGTC)]
Teravolt
August 03, 2020, 09:17:40 PM
post Re: Dual MOT tesla coil
[Spark Gap Tesla Coils (SGTC)]
MRMILSTAR
August 03, 2020, 08:30:38 PM
post Re: Budget USB cameras
[High Speed Filming]
missoum0514
August 03, 2020, 06:56:08 PM
post Re: Dual MOT tesla coil
[Spark Gap Tesla Coils (SGTC)]
Jun
August 03, 2020, 05:23:15 PM
post Re: Is my xray transformer a ferrite core and how would I drive it?
[Transformer (Ferrite Core)]
nielsquake
August 03, 2020, 05:02:26 PM
post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Max
August 03, 2020, 04:31:04 PM
post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
futurist
August 03, 2020, 10:05:59 AM
post Re: Is my xray transformer a ferrite core and how would I drive it?
[Transformer (Ferrite Core)]
Mads Barnkob
August 03, 2020, 08:21:26 AM
post Re: Is my xray transformer a ferrite core and how would I drive it?
[Transformer (Ferrite Core)]
nielsquake
August 02, 2020, 11:45:38 PM
post Re: How much is the voltage used in Corona Discharge tubes for ozone Generation?
[Transformer (Ferrite Core)]
davekni
August 02, 2020, 08:10:47 PM
post Re: How much is the voltage used in Corona Discharge tubes for ozone Generation?
[Transformer (Ferrite Core)]
Uspring
August 02, 2020, 07:27:33 PM
post Re: Corona lockdown thread, tell about your situation
[General Chat]
Uspring
August 02, 2020, 07:14:17 PM
post Re: Is my xray transformer a ferrite core and how would I drive it?
[Transformer (Ferrite Core)]
nielsquake
August 02, 2020, 06:58:34 PM
post Re: current limiting to parallel resonance circuit
[Beginners]
davekni
August 02, 2020, 06:49:59 PM
post Re: Dual MOT tesla coil
[Spark Gap Tesla Coils (SGTC)]
Jun
August 02, 2020, 05:10:12 PM
post Re: Dual MOT tesla coil
[Spark Gap Tesla Coils (SGTC)]
MRMILSTAR
August 02, 2020, 04:55:14 PM
post Re: How much is the voltage used in Corona Discharge tubes for ozone Generation?
[Transformer (Ferrite Core)]
UB_Serpent
August 02, 2020, 04:20:13 PM
post Re: How much is the voltage used in Corona Discharge tubes for ozone Generation?
[Transformer (Ferrite Core)]
UB_Serpent
August 02, 2020, 04:05:12 PM
post Dual MOT tesla coil
[Spark Gap Tesla Coils (SGTC)]
Jun
August 02, 2020, 01:07:54 PM
post current limiting to parallel resonance circuit
[Beginners]
plasma
August 02, 2020, 07:13:54 AM
post Re: How much is the voltage used in Corona Discharge tubes for ozone Generation?
[Transformer (Ferrite Core)]
davekni
August 02, 2020, 02:26:11 AM
post Re: FPS1000HD unboxing and first impression
[High Speed Filming]
missoum0514
August 01, 2020, 11:57:24 PM
post Re: How much is the voltage used in Corona Discharge tubes for ozone Generation?
[Transformer (Ferrite Core)]
TMaxElectronics
August 01, 2020, 10:24:21 PM
post Re: How much is the voltage used in Corona Discharge tubes for ozone Generation?
[Transformer (Ferrite Core)]
klugesmith
August 01, 2020, 03:59:43 PM
post Re: How much is the voltage used in Corona Discharge tubes for ozone Generation?
[Transformer (Ferrite Core)]
UB_Serpent
August 01, 2020, 06:22:53 AM
post Re: Is my xray transformer a ferrite core and how would I drive it?
[Transformer (Ferrite Core)]
nielsquake
July 31, 2020, 07:32:09 PM
post Re: Is my xray transformer a ferrite core and how would I drive it?
[Transformer (Ferrite Core)]
nielsquake
July 31, 2020, 06:15:27 PM
post Re: Is my xray transformer a ferrite core and how would I drive it?
[Transformer (Ferrite Core)]
nielsquake
July 31, 2020, 05:38:49 PM
post Re: Corona lockdown thread, tell about your situation
[General Chat]
klugesmith
July 31, 2020, 04:35:43 PM

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