General > General Technical Chat
Reduced resistance of resistor
WattsThat:
--- Quote ---I'm not sure how you can decide it's a bizarre and crappy report.
--- End quote ---
I dunno, maybe it had something to do with four or so years I spent in the QA/FA lab of what is now the worlds largest manufacturer of passive components helping to maintain the QPL for their MIL-R-55182 line of fixed resistors?
Okay, so we’re not talking about MIL-R-33007 parts here in what is no doubt a consumer electronic product, but I dissected enough precision wire-wounds in competitive analysis studies and compiled the data to know that report is extremely broad in nature and would be written based on data that is exclusive to mil qualified products. While the construction of QPL (qualified product listing) parts is most times identical to their commercial counterparts, the testing that is performed on QPL parts can so significantly skew the observed failure mode data cited in the “report” that referencing that data in the context of this online discussion is downright, well, silly.
For starters, we know nothing about what kind of resistor the OP is dealing with. A 9 watt device could be anything and for all we know, he could be measuring it in circuit. We know absolutely nothing about this mystery resistor and you’re hanging your hat on a very broad, generalized report that is based on components that cost a minimum ten to a hundred times what the consumer world pays. Why you think that report is somehow relevant here is beyond my comprehension.
You’ve made numerous assumptions about what the mystery part is and have assumed you identified the failure mode and provided a link to a report that in your mind validates your assumptions. Whoop-dee-doo. Assume away. I’ll wait for more data from the OP before I start forming any opinions about what may be in play here.
wraper:
I suspect there is R56 written on rather than 56R.
engrguy42:
--- Quote from: WattsThat on April 11, 2020, 11:01:30 pm ---
--- Quote ---I'm not sure how you can decide it's a bizarre and crappy report.
--- End quote ---
I dunno, maybe it had something to do with four or so years I spent in the QA/FA lab of what is now the worlds largest manufacturer of passive components helping to maintain the QPL for their MIL-R-55182 line of fixed resistors?
Okay, so we’re not talking about MIL-R-33007 parts here in what is no doubt a consumer electronic product, but I dissected enough precision wire-wounds in competitive analysis studies and compiled the data to know that report is extremely broad in nature and would be written based on data that is exclusive to mil qualified products. While the construction of QPL (qualified product listing) parts is most times identical to their commercial counterparts, the testing that is performed on QPL parts can so significantly skew the observed failure mode data cited in the “report” that referencing that data in the context of this online discussion is downright, well, silly.
For starters, we know nothing about what kind of resistor the OP is dealing with. A 9 watt device could be anything and for all we know, he could be measuring it in circuit. We know absolutely nothing about this mystery resistor and you’re hanging your hat on a very broad, generalized report that is based on components that cost a minimum ten to a hundred times what the consumer world pays. Why you think that report is somehow relevant here is beyond my comprehension.
You’ve made numerous assumptions about what the mystery part is and have assumed you identified the failure mode and provided a link to a report that in your mind validates your assumptions. Whoop-dee-doo. Assume away. I’ll wait for more data from the OP before I start forming any opinions about what may be in play here.
--- End quote ---
I provided data. You guys provide nothing but unsupported generalizations, and act like your word is truth.
I'm just saying that the experiences of one or two guys may not reflect the OP's situation or the world in general. I tend to put more belief in people who write papers and provide data and references.
Doesn't mean it's right, and I have no clue (nor do I care) what the right answer is. I'm just cautioning people to tap the breaks before you proclaim you hold the truth.
Someone says wirewound power resistors are infallible and cannot go lower value. A well-referenced report says otherwise. As a minimum that should cause someone to be open to the possibility they're wrong.
Basic engineering.
langwadt:
--- Quote from: engrguy42 on April 11, 2020, 11:09:16 pm ---
--- Quote from: WattsThat on April 11, 2020, 11:01:30 pm ---
--- Quote ---I'm not sure how you can decide it's a bizarre and crappy report.
--- End quote ---
I dunno, maybe it had something to do with four or so years I spent in the QA/FA lab of what is now the worlds largest manufacturer of passive components helping to maintain the QPL for their MIL-R-55182 line of fixed resistors?
Okay, so we’re not talking about MIL-R-33007 parts here in what is no doubt a consumer electronic product, but I dissected enough precision wire-wounds in competitive analysis studies and compiled the data to know that report is extremely broad in nature and would be written based on data that is exclusive to mil qualified products. While the construction of QPL (qualified product listing) parts is most times identical to their commercial counterparts, the testing that is performed on QPL parts can so significantly skew the observed failure mode data cited in the “report” that referencing that data in the context of this online discussion is downright, well, silly.
For starters, we know nothing about what kind of resistor the OP is dealing with. A 9 watt device could be anything and for all we know, he could be measuring it in circuit. We know absolutely nothing about this mystery resistor and you’re hanging your hat on a very broad, generalized report that is based on components that cost a minimum ten to a hundred times what the consumer world pays. Why you think that report is somehow relevant here is beyond my comprehension.
You’ve made numerous assumptions about what the mystery part is and have assumed you identified the failure mode and provided a link to a report that in your mind validates your assumptions. Whoop-dee-doo. Assume away. I’ll wait for more data from the OP before I start forming any opinions about what may be in play here.
--- End quote ---
I provided data. You guys provide nothing but unsupported generalizations, and act like your word is truth.
I'm just saying that the experiences of one or two guys may not reflect the OP's situation or the world in general. I tend to put more belief in people who write papers and provide data and references.
Doesn't mean it's right, I'm just cautioning people to tap the breaks before you proclaim you hold the truth.
Someone says wirewound power resistors are infallible. A well-referenced report says otherwise. As a minimum that should cause someone to be open to the possibility they're wrong.
Basic engineering.
--- End quote ---
I'd think something like bifilar wound for reduced inductance add alot more risk of shorts causing low resistance
floobydust:
--- Quote from: engrguy42 on April 11, 2020, 11:09:16 pm ---[...] Someone says wirewound power resistors are infallible and cannot go lower value. A well-referenced report says otherwise. As a minimum that should cause someone to be open to the possibility they're wrong.
Basic engineering.
--- End quote ---
Certain safety standards where resistance decreases in value create a hazardous condition, specify using wirewound resistors which are considered "infallible" in them.
The Navy report is too vague to be useful and contradicts the safety standards and decades of knowledge. Perhaps they tested plastic encapsulated wirewound resistors but even then, their core is ceramic and would not deform. I think the report is not an authority.
Stick to your basic engineering, while some of us work with real world designs.
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