------Question for CH-200 Please Put your question below------
I am interested in using this inductor with AC excitation, as a simple AC load for inverter testing, but the datasheet only gives its current rating for DC use. I would really like to know: (1) How does the CH-200’s current rating vary with AC frequency? This would be with no DC bias. (2) How does the AC resistance change with frequency? (3) What is the range of voltage and frequency it can reasonably be used for?
Greetings,
Inductor current ratings are commonly derived from two limiting factors, either the temperature rise due to conduction I2R losses at DC or reduction of inductance value due to saturation at some specified test frequency.
Insofar as the product series appears to be targeted toward AC-DC conversion applications based on simple rectification, it’s reasonable to infer that the limits mentioned in the datasheet are of the first type.
It can also be seen that the core construction is of the laminated steel type typical of products designed for use at utility frequencies. The relatively large “grain size” of the laminations compared to that of powder-based core materials leads to rapid increases in core losses with frequency. One can likely find examples of this core type being used in 400Hz aircraft systems, but other materials become preferable soon after that point.
In response to your questions:
It doesn’t have a “rating” per-se beyond DC, but since AC operation introduces core losses on top of I2R losses, the temperature-limited carrying capacity of the device will be lower at any given AC frequency than at DC. Also, given the beefy DC rating one can presume that the windings are of a relatively large gauge, such that skin effect will start to make itself noticed at a relatively low frequency, adding to the difficulty.
That’s a complex question to address in detail, but passives tend to reverse their character beyond some resonant point; capacitors start to look like inductors and vice-versa.
The discussion in this post may be found informative. The bottom line is that it’s up to you to determine what’s “reasonable” for your purposes, and if your intentions differ substantially from the conditions at which a manufacturer specifies and characterizes a product, the risks that attend off-label use are yours.
All that said, just how different is the construction of this device likely to be from the devices for which you’re wanting to use it as a stand-in?
