Input on cheap stick power supply please.

[TDegenhart]

A link for more on optical pyrometry.

Optical Pyrometers How They Work and Who Still Makes Them

A lot of articles talk about a black body. Radiation from a black body is at emissivity of 1 so correction is not needed. A black body can be a cavity as in a closed furnace at uniform temperature. If, for instance, the crucible is covered but with a peep hole, then the radiation is close to being from a black body.

Tom

 

[Miguels244]

A link for more on optical pyrometry.

Optical Pyrometers How They Work and Who Still Makes Them

A lot of articles talk about a black body. Radiation from a black body is at emissivity of 1 so correction is not needed. A black body can be a cavity as in a closed furnace at uniform temperature. If, for instance, the crucible is covered but with a peep hole, then the radiation is close to being from a black body.

Tom

That is correct.
Be sure the arc is off when reading, and the atmosphere will have some effect. IIRC

 

[TDegenhart]

I didn't discourage you did I ?

Tom

 

[DDoug]

The tm-300 is a good supply, I have the tm-500.

However, if you search for the TIG version (forgot the designation), you get
a remote control capability, using IIRC a magnetic amplifier
circuit.

So you could control the amperage from a PLC or computer
if wanted.

The tm-300/500 runs a simple screw pulling a core up/down
for amperage control.

 

[TDegenhart]

Three (3) small crucibles available

Lost Creek Machine New and Used Machine Tools

Tom

 

[TDegenhart]

The tm-300 is a good supply, I have the tm-500.

However, if you search for the TIG version (forgot the designation), you get
a remote control capability, using IIRC a magnetic amplifier
circuit.

So you could control the amperage from a PLC or computer
if wanted.

The tm-300/500 runs a simple screw pulling a core up/down
for amperage control.

You must be an old fart. No one talks about mag amps anymore but old people.

Tom

 

[DDoug]

You must be an old fart. No one talks about mag amps anymore but old people.

Tom

I'm not as old as you, I'm still gainfully employed.....I just happen to own
machines older than myself.

 

[Toolbert]

I'm reminded of a recent tour of the local Nucor mill, watching the melt furnace control board as the 3 giant water cooled graphite electrodes lower slowly into the scrap charge, and stop when they're white hot and the board shows they're pulling a steady 50 megawatts from the grid. I think there's actually a feedback loop that controls the depth of the electrodes to maintain a particular current draw. 3 electrodes, 3 phase, so there's a strong rotary field, but with luck that's just a question of efficiency.

 

[DDoug]

I'm reminded of a recent tour of the local Nucor mill, watching the melt furnace control board as the 3 giant water cooled graphite electrodes lower slowly into the scrap charge, and stop when they're white hot and the board shows they're pulling a steady 50 megawatts from the grid. I think there's actually a feedback loop that controls the depth of the electrodes to maintain a particular current draw. 3 electrodes, 3 phase, so there's a strong rotary field, but with luck that's just a question of efficiency.

My cousin used to run the arc furnace at Wampum, PA.

Said he could see the lights of the town dip as he started....

I wonder if he rang up New Castle power plant and asked for permission ?

FWIW a local factory had their own power plant (3, 8 meg turbines)
and my friend would ring them up before starting the large scrap shredder.
He said they would start banking coal, and call him back in about 1/2 hour
and give the O.K.

 

[Miguels244]

I'm reminded of a recent tour of the local Nucor mill, watching the melt furnace control board as the 3 giant water cooled graphite electrodes lower slowly into the scrap charge, and stop when they're white hot and the board shows they're pulling a steady 50 megawatts from the grid. I think there's actually a feedback loop that controls the depth of the electrodes to maintain a particular current draw. 3 electrodes, 3 phase, so there's a strong rotary field, but with luck that's just a question of efficiency.

The rotary field is actually a good thing, it stirs the matte.

There’s a reason smelting is located near power plants these days...and coal fields in the past.