Dummy Loads: Wirewound VS Aluminum Shell? - Page 3 - diyAudio
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Old 5th February 2014, 06:07 PM   #21
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Quote:
Originally Posted by bear View Post

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.

_-_-

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 )
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Old 5th February 2014, 06:10 PM   #22
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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!
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Old 5th February 2014, 09:53 PM   #23
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I was saying the aluminum encased resistors (like Dale) often blow themselves out of the ends when the power level is exceeded. Whereas the ceramic wire wounds get hot - the resistance may change, but they withstand dramatic over current much better.
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Old 5th February 2014, 09:58 PM   #24
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I was saying the aluminum encased resistors (like Dale) often blow themselves out of the ends when the power level is exceeded.
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Old 6th February 2014, 02:21 AM   #25
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1000 Watt 1 Ohm 10 Ceramic Wire Wound Resistor Part FSE100002E1R00KE 1000W | eBay Here's a 1ohm 1kwatt wire wound I found on ebay....way cheaper than trying to make your own. This is strictly for testing "HC" amplifiers that can handle 1ohm loads.
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Old 6th February 2014, 09:27 AM   #26
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Originally Posted by infinia View Post
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.
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Old 6th February 2014, 09:29 AM   #27
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Originally Posted by jeanious2011 View Post
1000 Watt 1 Ohm 10 Ceramic Wire Wound Resistor Part FSE100002E1R00KE 1000W | eBay Here's a 1ohm 1kwatt wire wound I found on ebay....way cheaper than trying to make your own. This is strictly for testing "HC" amplifiers that can handle 1ohm loads.
These are not ceramic resistors.

They are wire wound metal resistors wound onto a ceramic core.
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Old 6th February 2014, 05:06 PM   #28
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Originally Posted by AndrewT View Post
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
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Old 6th February 2014, 06:01 PM   #29
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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
Quote:
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.
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Old 6th February 2014, 06:07 PM   #30
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uhh there is a learning curve with making yer own NiCr resistors. terminating them properly is just the tip. not recommended
just buy some non infrared space heaters > heavier and longer wire inside safely mounted and cooled already.
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