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hfeld_LF_de&hfeld_MF_de
When using a low frequency of 2 kHz (left), the magnetic field penetrates deeper into the component
(right image: use of a medium frequency of 12.5 kHz).
a heating time of 8.5 seconds to achieve the desired
temperature distribution (without exceeding the
maximum temperature).
Faster Heating within the Volume
“We use numerical calculations to design faster, more accurate
processesthen would be possible if using trial and error—in
other words, we start by building an inductor, testing it, and
adjusting/redesigning as needed. The results also translate
very well into practice from a qualitative standpoint and in
this respect they make the advantages that the LF technology
provides very clear,” explains Mr. Dirk Schlesselmann, Deputy
Head of Application Technology Research and Development
at eldec. “The lower frequencies heat up the inside of the unit
faster because the magnetic field penetrates the component.
This is why we can significantly reduce the cycle time compared
to when using medium frequencies. Moreover, it’s easier
to remain within the desired temperature process window
and the risk of overheating recedes. Last but not least, the
occurring temperature gradients are smaller. And, in the end,
47 | january-february 2019 |
this means that the risk of cracks forming on the component
is smaller.” With that in mind, the induction specialists at
EMAG eldec already offer a wide range of generators with LF
technology (power output: 50 to 500 kW, frequency range: 2
to 8 kHz). Their potential areas of application are tremendous:
The technology offers great benefits to applications, such as
pre-heating prior to welding gear wheels, joining of stators
in electric motor housings, infusing stators or annealing
after hardening, for instance. “In principle, it can make sense
wherever heating within the volume should be performed
at low cycle times. However, our LF generators not only
ensure faster processes, but also operate with higher process
reliability. The devices also score points with their cutting-
edge technology. They use the robust and well-established
IGBT transistor technology, have an efficiency of more than
90 percent and their energy is precisely measured out. We
also want to bring these benefits to the LF segment of the
market in a targeted manner as of today.”
https://www.emag.com/
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