Glossary · Measures
Cost per kiloamp-meter and the conditions behind a quotation
Cost per kiloamp-meter is conductor price per meter divided by critical current in kiloamperes at specified conditions.
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- DefinitionCost per kiloamp-meter ($/kA·m)
- Conductor price per meter divided by critical current in kiloamperes under stated test conditions. It normalizes purchase price by current-carrying capacity, rather than total device cost.
What the metric calculates
The metric combines the conductor’s purchase price per unit length with its current-carrying capacity. Divide price per meter by critical current expressed in kiloamperes to obtain dollars per kiloamp-meter. The denominator combines current and length; it is not current divided by length. This normalization lets a buyer compare differently sized conductors, provided the current rating describes the same test conditions and acceptance criterion. [1]
The value is a cost-performance measure for the conductor, not the price of transporting electricity through a complete system. It does not include operating time, energy delivered, refrigeration, or conversion equipment. It also does not determine the quantity of conductor a magnet needs. Winding geometry, field requirements, operating margin, and allowable current influence that quantity before the normalized price can be translated into a project budget. [1][2]
Match the current rating before comparing
Critical current depends on temperature, applied magnetic field, field orientation, strain, and the measurement criterion. A quotation normalized using a warm, low-field test can look different when evaluated at a colder, high-field operating point. Comparing values calculated at unmatched conditions can reward the test setup rather than the conductor. The operating point and electric-field criterion belong beside the metric in any procurement comparison. [2][3]
A tape’s width, stabilization, substrate, and accepted length quality can affect both price and performance. Long-length uniformity and the treatment of rejected sections matter to the usable delivered quantity. Order size, inspection requirements, and commercial terms also change a quotation. A historical publication can explain the metric or record an earlier cost target, but it should not be presented as a current supplier price. [1][2]
From conductor cost to device cost
A magnet budget includes cabling or tape assembly, insulation, winding, heat treatment where required, joints, structural support, and protection. A cooling system adds equipment, integration, maintenance, and electricity consumption. Higher current capacity may reduce winding requirements, but a difficult fabrication process can offset that advantage. A useful comparison therefore separates conductor cost-performance from the installed and operating cost of the whole device. [1][2]
Request quotations against the same conductor specification and evaluate critical current at the intended conditions. Then estimate qualified length, fabrication yield, reaction requirements, cooling, and replacement constraints. A normalized price is helpful when those assumptions are visible. It becomes misleading when treated as a universal league table among materials or as proof that a superconducting device will cost less than a conventional alternative. [1][2]
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