Dummy Loads: Wirewound VS Aluminum Shell?

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Wirewound is superior to the aluminum "Dale" type resistors for high power testing. Unless you ramp up the temp slowly there is the danger of blowing the ends out of the aluminum case type. I avoid them wherever possible. Too bad, because they *look* good.

You can make a wirewound GLOW red and it is ok usually.

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I often wondered about those Dales sure are pretty IE don't exceed ratings even for pulsed.
glowing the resistance is usually increasing ( light bulbs )
 
One could buy replacement wire coils for infra red heater tubes.
They were relatively cheap. Don't know if they are still available.
Need special flux to solder to the ends.


This is a bad idea/
infrared uses brilliantly glowing elements ( means the resistance is highly variable ) would have difficulty starting a PA into a short circuit.
the ends are welded or mechanically fixed you cant solder these!
 
This is a bad idea/
infrared uses brilliantly glowing elements ( means the resistance is highly variable ) would have difficulty starting a PA into a short circuit.
the ends are welded or mechanically fixed you cant solder these!
When connected to 240Vac they glow red.

We are discussing making dummy load resistors.
The wire is possibly nichrome and makes fairly good resistors when used within their power rating, i.e. when they feel no more than warm to the "finger touch"

BTW,
the wire is NOT welded.
It arrives as preformed coil wire, that is screw fixed into the terminals of the heater.
 
When connected to 240Vac they glow red.

We are discussing making dummy load resistors.
The wire is possibly nichrome and makes fairly good resistors when used within their power rating, i.e. when they feel no more than warm to the "finger touch"

BTW,
the wire is NOT welded.
It arrives as preformed coil wire, that is screw fixed into the terminals of the heater.


the wire will be very hot for efficient use of NiChrome, but should not be glowing as it is neither a very safe or reliable condition in dummy loads.
RE infrared elements (pls note 240V is not common here) even if a source is found many more elements would be needed for a safe load )
welded is the best & most common termination ( it has to connected to some conductor in the chain) soldering does not make sense
 
750W of nichrome wire for a 240Vac supply will have a hot resistance of about 80r.
The resistance is likely to be a bit less when
they feel no more than warm to the "finger touch"
I'll guess 70r

That is enough wire to make 9 off 8r0 dummy resistors.
Parallel them or series them or series parallel them.

Or just buy a reel of nichrome wire, if you want to make your own.
 
Afaik there are no "ceramic" resistors, unless you count blown transistors and call the silicon "ceramic".

Ceramic resistors are a term used to describe a resistance element, usually nichrome wire embedded in a ceramic form or wound on top of a ceramic form.

There are other forms of resistance elements, films and foils, they can also be placed or made on top of a ceramic substrate. The purpose of the substrate is to conduct heat away and provide a stable structure.

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