AC Frequency

[megbers]

How would one increase the frequency of an AC signal? I am looking into inductive heat treating and to my surprise the units are 10k dollars and up. I am trying to go from 110v, 60 hz to 110v, ~10kHz. Any ideas? Thanks

 

[sreid]

Possibly, an audio amplifier driven from a function (sine wave) generator. Higher power is available in guitar amplifiers.

 

[jraef]

I would think RF would be a problem if you did that. Heat trace cable has no need to be shielded at this point, so I doubt it is available.

 

[Andreb]

Here is a home built unit.

http://www.youtube.com/watch?v=ctPtOONtGGg

http://webpages.charter.net/dawill/tmoranwms/Elec_IndHeat1.html

 

[ScottyUK]

I built something like this for my university thesis, except mine was a current-source inverter fed on a diet of 415V 3 phase at 20kW and an ample supply of cooling water.

How much power are you trying to transfer into the load? Audio amps for the semi-pro market are readily available up to about 1kW into a small load. A coupling transformer might be needed to impedance match the load coil to the amplifier. They're fun to build, especially trying to get hold of small quantities of large section ferrites.


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Sometimes I wake up Grumpy.
Other times I just let her sleep!

 

[ScottyUK]

I've just watched the youtube clip. That is disturbingly similar to the thing I built, but a lot smaller. The highlight of my project was getting over 7000 people evacuated from the engineering buildings one snowy November day - my birthday funnily enough - after smoke started pouring out of a cable duct. There was a big inquiry about why the breakers had not tripped but I wasn't privy to any of that.

 

[itsmoked]

Scored some points there Scotty!

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[megbers]

Very helpful info guys, thanks! Im looking to heat a ~1" dia steel rod to only about 400 deg on the surface. I dont think i need alot of power.

 

[itsmoked]

If you are heating a conductor, (steel), can't you just run a current thru it?

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[ScottyUK]

Ok, so the question is are you trying to achieve surface heating only or bulk heating? 10kHz suggests surface only in which case you need a powerful source to get energy into the surface layers faster than conduction can get it away from the surface into the core of the metal. Is this for a surface hardening application where you need a hard surface over a softer core? Also do you mean 400C or 400F? Big difference in power! I assume 400C for a metal hardening application.

BTW, have you considered adapting a bearing heater?

'Smoked,

My project was notorious enough before this incident: setting the university on fire elevated me to demigod status.


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Sometimes I wake up Grumpy.
Other times I just let her sleep!

 

[itsmoked]

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[Skogsgurra]

You are not alone Scotty!

There is a commissioning engineer at ABB. He is named Smokey after he burned down a paper mill in Israel. He is also quite famous.

Gunnar Englund

http://www.gke.org

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