Are old high voltage components from microwave ovens useful, or should
I chuck them out in the trash?

I have several transformers that look like they are good for quite a
few watts of power, some of the high voltage diodes and several
blowers. I've been saving them.

Can they be used for power supplies for rf transmitters? Are the
blowers any good for cooling large tubes in transmitters?

Thanks,

Al


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Some years ago, there was an article in one of the ham mags about converting
microwave ovens into high power microwave ham transmitters. It might give
some helpful background info. Unfortunately I can't remember the timeframe
or which mag ran it. Maybe someone else in the group can remember???

Joe
W3JDR

"Albert" wrote in message
...
Are old high voltage components from microwave ovens useful, or should
I chuck them out in the trash?

I have several transformers that look like they are good for quite a
few watts of power, some of the high voltage diodes and several
blowers. I've been saving them.

Can they be used for power supplies for rf transmitters? Are the
blowers any good for cooling large tubes in transmitters?

Thanks,

Al


-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

The transformer is good for 1500 to 2500 VRMS at 0.5 A or more.

More info at:

http://www.repairfaq.org/sam/gadget.htm#gadmot

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"W3JDR" writes:

Some years ago, there was an article in one of the ham mags about converting
microwave ovens into high power microwave ham transmitters. It might give
some helpful background info. Unfortunately I can't remember the timeframe
or which mag ran it. Maybe someone else in the group can remember???

Joe
W3JDR

"Albert" wrote in message
...
Are old high voltage components from microwave ovens useful, or should
I chuck them out in the trash?

I have several transformers that look like they are good for quite a
few watts of power, some of the high voltage diodes and several
blowers. I've been saving them.

Can they be used for power supplies for rf transmitters? Are the
blowers any good for cooling large tubes in transmitters?

Thanks,

Al

"Sam Goldwasser" wrote in message
...
The transformer is good for 1500 to 2500 VRMS at 0.5 A or more.

I would check to see if these transformers are continuously rated, I seem to
recall they are rated for intermittent use only.

Theo

Theo wrote:
"Sam Goldwasser" wrote in message
...

The transformer is good for 1500 to 2500 VRMS at 0.5 A or more.


I would check to see if these transformers are continuously rated, I seem to
recall they are rated for intermittent use only.

Theo



They are also built to have high leakage inductance, for current
limiting when you put your steel coffee cup in there. This is done by
having physically separate windings and a laminated-steel wedge in the
window in the core. You have to knock that wedge out.

There was an article in QST or QEX about using microwave parts to build
power supplies for linears. Very interesting. Very scary, considering
that the author also used old refrigerator drawers as the case...

I saved the pieces from my old microwave in case I ever want to build
something that puts out more than 5W.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

"Theo" writes:

"Sam Goldwasser" wrote in message
...
The transformer is good for 1500 to 2500 VRMS at 0.5 A or more.

I would check to see if these transformers are continuously rated, I seem to
recall they are rated for intermittent use only.

Well, microwave ovens can run for hours at full power so I guess that
rates continuoue? It is true they may NOT be continuous rated at
low or no load due to core saturation.

--- sam | Sci.Electronics.Repair FAQ Home Page: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Site Info: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header is ignored.
To contact me, please use the feedback form on the S.E.R FAQ Web sites.

"Albert" wrote in message
...
Are old high voltage components from microwave ovens useful, or should
I chuck them out in the trash?

I have several transformers that look like they are good for quite a
few watts of power, some of the high voltage diodes and several
blowers. I've been saving them.

Can they be used for power supplies for rf transmitters? Are the
blowers any good for cooling large tubes in transmitters?

Of course you can use the diodes and the capacitors ;-)
There are some articles on th Internet about converting the transformer for
a spot welder.
A also saw an article on using the magnetron as a PLL like amplifier to put
out 1kw at 13 cm. I can forward the link if you want.

Wim

Hi Tim,

There was an article in QST or QEX about using microwave parts to
build power supplies for linears. Very interesting. Very scary,
considering that the author also used old refrigerator drawers as the
case...

Just curious: Do people still build linears with tubes and HV supplies
or is it much cheaper now to use transistors? Mine were all tubes but
that was about 20 some years ago when FETs and BJT were just way out
there in terms of cost.

Regards, Joerg

http://www.analogconsultants.com

Just curious: Do people still build linears with tubes and HV supplies
or is it much cheaper now to use transistors? Mine were all tubes but
that was about 20 some years ago when FETs and BJT were just way out
there in terms of cost.

As one example: Ameritron builds solid-state ham-band amplifiers of up
to 600 watts output (their "ALS" series). Starting at the 600-watt
point, and going up to the 1500-watt legal limit, Armitron's amps are
all based on tubes. There are legal-limit HF amps which use only a
single tube (e.g. a 3CX1500A/8877 triode, running at about 2500 volts)

According to a talk I saw recently, commercial television broadcasters
have moved almost exclusively to solid-state RF amplifiers for their
newer stations. No one set of transistors can provide thenecessary
power, so the amps use a large number of smaller modular amplifiers
operating in parallel - I think the basic "brick" we were shown was
capable of a couple of hundred watts. I haven't seen any ham-band
amplifiers using this modules-in-parallel approach, although I'm
sure one could be built.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Hi Dave,

Thanks for explaining. 600W is pretty good power already. Since the commercial amps are bricks it seems they must have good protection against sudden mismatches as well.

I remember when I had a coil in the antenna open, which was immediately followed by an exploding coax cable portion. The tubes didn't even flinch but in the 70's just the opening coil would have immediately destroyed even a small transistor amp because the SWR network wasn't fast enough to shut it down.


Regards, Joerg

http://www.analogconsultants.com