what mosfet to use for an induction heater

[rickselectricalprojects]

hi everyone
i want to build this induction heater:

http://www.rmcybernetics.com/projects/DIY_Devices/diy-induction-heater.htm
the mosfets they use are STP30NF10's. that mosfet is a 100v 35a n channel mosfet with a on resistance (RDS) of <0.045 ohms. because i dont have any STP30NF10's or any IRF540N's (the IRF540N is very similar) can i use a Toshiba K2837 which is a 500v 20a mosfet with an on resistance (RDS) of 0.21 ohms. that schematic is very, very, very similar to the popular ZVS driver. people say that with ZVS drivers the mosfet's RDS should not be over 0.15 ohms but people have used the IRFP460 which has an RDS of 0.22 ohms and they worked. but they were running flyback transformers and i have NO interest in doing that.
so my question is will the K2837 work or should i buy different mosfets (the IRF540N are $5.95 each at jaycar electronics)
thanks in advance

 

[rickselectricalprojects]

i forgot to add this:
i know the higher the RDS the more hot the mosfets will get. i dont care if the K2837 is running a bit hot but i dont want it to fail because of the heat.

 

[Old Steve]

Rick, RS Components (Oz) have the STP30NF10 in stock at the moment. Only $1.84 each. They'd get them to you within a couple of days, and have free delivery for online orders:-
http://au.rs-online.com/web/p/mosfe...D424F5448267573743D53545033304E46313026&sra=p

Don't settle for the K2837 or the other one. They might cook.

Edit: RS deliver by courier. Because of this, I always feel bad about placing really small orders with them, and eventually if enough people do it, it could lead to an end of their free delivery, so if you also need other parts, now's the time.

And you'll have to keep us updated on how this project progresses. I'll be interested to see

It just struck me that, unlike me, you might have a well-stocked local Jaycar. (I have to order online, and RS is faster than Jaycar.) If that's the case, I'd probably buy the IRF540N if I were you. As you say, it's very similar.

 

[Minder]

The alternative is to get creative and come up with a water cooled heatsink, also the caps have to be very low ESR the WIMA MKP4 are a good source, they also carry the tank current so cooling these is a good idea if higher cycle times are needed.
M.

 

[rickselectricalprojects]

The alternative is to get creative and come up with a water cooled heatsink, also the caps have to be very low ESR the WIMA MKP4 are a good source, they also carry the tank current so cooling these is a good idea if higher cycle times are needed.
M.

i would like to water cool the fets, cap and the work coil but i dont have a pump. i am thinking at the end of the year when i get a big 8 week holiday when school finishes for the year i have plans on making a big induction heater, i would use this schematic:

(http://4hv.org/e107_plugins/forum/forum_viewtopic.php?129196)
and i would run it off of a couple of server power supply's in series (36V or 48v)
thanks for your help

 

[rickselectricalprojects]

Rick, RS Components (Oz) have the STP30NF10 in stock at the moment. Only $1.84 each. They'd get them to you within a couple of days, and have free delivery for online orders:-
http://au.rs-online.com/web/p/mosfe...D424F5448267573743D53545033304E46313026&sra=p

Don't settle for the K2837 or the other one. They might cook.

Edit: RS deliver by courier. Because of this, I always feel bad about placing really small orders with them, and eventually if enough people do it, it could lead to an end of their free delivery, so if you also need other parts, now's the time.

And you'll have to keep us updated on how this project progresses. I'll be interested to see

It just struck me that, unlike me, you might have a well-stocked local Jaycar. (I have to order online, and RS is faster than Jaycar.) If that's the case, I'd probably buy the IRF540N if I were you. As you say, it's very similar.

i went out to jaycar and forked out $12 for two IRF540N mosfets. i am currently prototyping now using the K2837 and some other parts i don't plan on using on my final version and soldering them to scrap PCB board that i had lying around because i don't want to push to much power through a breadboard.
also is element14 as fast as rs components? do they do courier?
thanks for your help

 

[Old Steve]

i went out to jaycar and forked out $12 for two IRF540N mosfets. i am currently prototyping now using the K2837 and some other parts i don't plan on using on my final version and soldering them to scrap PCB board that i had lying around because i don't want to push to much power through a breadboard.
also is element14 as fast as rs components? do they do courier?
thanks for your help

I couldn't say, Rick. I've never dealt with element14. You might be lucky, but most suppliers only use Australia Post. Mind you, element14 might have an option for courier delivery, but I doubt if it's free.

Update: I just checked the element14 website:

1.a. Free Australia Post Express – No Signature Required

element14 offers free delivery for all orders over AUD45 (excluding GST) via Australia Post.

(If your order is less than $45, it's $12.95 delivery for up to 20kg.)

 

[Minder]

Any practical duty cycle you are going to need water cooling IMO.
http://kaizerpowerelectronics.dk/general-electronics/royer-induction-heater/
M.

 

[Old Steve]

i would use this schematic:

Here's that full-sized image back:-

 

[rickselectricalprojects]

I couldn't say, Rick. I've never dealt with element14. You might be lucky, but most suppliers only use Australia Post. Mind you, element14 might have an option for courier delivery, but I doubt if it's free.

Update: I just checked the element14 website:

(If your order is less than $45, it's $12.95 delivery for up to 20kg.)

the thing with element14 is is your $12.95 away from $45 then you would just get $12.95 worth of spare components.
jaycars price for components is ridiculous and i might try ordering from both rs and element14 and see which seller has the fastest shipping. i have a feeling that it will be rs components.

 

[Old Steve]

the thing with element14 is is your $12.95 away from $45 then you would just get $12.95 worth of spare components.
jaycars price for components is ridiculous and i might try ordering from both rs and element14 and see which seller has the fastest shipping. i have a feeling that it will be rs components.

My money's on RS too. I placed an order on Monday night, the parts that were in the country were dispatched Tuesday and I got them Wednesday, then got the parts that they said were only in stock in the UK today. Pretty good.

 

[rickselectricalprojects]

My money's on RS too. I placed an order on Monday night, the parts that were in the country were dispatched Tuesday and I got them Wednesday, then got the parts that they said were only in stock in the UK today. Pretty good.

wow three days, thats great. i will definetly start buying from rs then but i will give element14 a try as well.