Inductor rating

Inductor. The channel inductor assembly consists of a steel box or case that contains the inductor refractory and the inductor core and coil assembly. The channel is formed within the refractory. Inductor power ratings range from 25 kilowatts for low temperature metals to 5000 kilowatts for molten iron. Forced air is used to cool the lower power inductors, and water is generally used to cool inductors rated 500 kilowatts or more. 

This is the relationship between the average inductor current and the load current. Note that in Figure 1-13, in the embedded table, we have asked for an inductor rated for 1.2 x I0/(l — D). The factor 1.2 comes from the fact, that by typical design criteria, the peak of the inductor current waveform is about 20% higher than its average. So we need to look for an inductor rated at least for a current of 1.2 x II. 

But then, the inductor would probably be saturating For example, if we are using a 5-A fixed current limit buck switcher IC for a 3-A application, we have probably picked an inductor rated for only around 3 A. But when we short the output, the current momentarily hits the current limit (which may be around 5.3 A for a 5-A buck switcher ). 

A related issue is the case when a buck IC is used in a so-called inverting configuration . We should realize that in doing so actually the topology has in effect changed from a buck to a buck-boost. So now we just cannot get 5 A of load current from a declared 5 A IC. How much load current is possible depends on the specific input-output conditions. So again, our peak current is not close to 5 A, nor should the inductor rating be 5 A . Or we will certainly be frozen into a July 4th timeframe forever. 

A typical m el ter iastalled in a medium sized brass foundry contains 4500 kg of brass and its inductor is rated 500 kilowatts. Brass is an alloy containing copper and zinc. Zinc vaporizes at temperatures weU below the melting temperature of the alloy. The channel iaductor furnace s low bath temperature and relatively cool melt surface result in low metal loss and reduced environmental concerns. Large dmm furnaces have found use in brass and copper continuous casting installations. 

Designing the output filter choke La) in a forward-mode converter is done first. This simple procedure can be seen in Section 3.5.5. A key design factor is to design the inductor to operate in the continuous current mode. The typical value of peak inductor current is 150 percent of the rated output current. The typical valley (minimum) current is about 50 percent of the rated output current. 

The principal characteristic of induced reactions of this type which have not been stressed so far, is that the extent of the induced change greatly decreases and in most cases reaction even ceases in the presence of chain-breaking substances. The induced reaction can be suppressed by any substances reacting with chain carriers at a higher rate than does the acceptor, and the product of the reaction of the suppressor can easily react with the inductor. Since the concentration of the chain carriers is generally low, the supressors of induced chain reactions exert considerable effect even in small quantity. The effect is particularly pronounced when the suppressor reacts reversibly. 

It was found by DeLury that the overall rate of reduction of chromate is practically unaffected by the concentration of iodide, i.e. the sum of the rates of formation of iodine and aresenic(V) is constant and just equal to the rate at which chromate is reduced in a raction mixture containing no iodide (Fig. 1). The rate of oxidation of arsenite at a sufficiently high concentration of iodide decreases to i of its original value this is in accordance with the value of ci = 2 found. Fig. 1 well illustrates the general feature of coupled reactions, that the reaction of the inductor is always inhibited by the acceptor. The induced oxidation of iodide can... 

Author s Comments That s obviously not true. The customer has had problems at 1A load too. So this explanation, even if true (and it is not) does not really fit the set of clues provided by the customer. It could be one reason, but is not the explanation. As indicated previously, the saturation rating of most inductors is not a cliff over which you suddenly fall off into a timeless abyss. Saturation usually just means the inductance has fallen by about 20 to 30% from its initial value. So in going further, say from 3A to 3.5A, you can expect the inductance to fall to about 50% of its initial value. But rarely any more For sure, it doesn t suddenly morph into a resistor. ... 

In contrast to a capacitor, an inductor will allow the passage of DC and low-frequency AC much more freely than high-frequency AC. This is because the amount of back EMF generated is proportional to the rate of change of the current... 

Current Draw a build-up exponential curve (solid fine) to show how current flows when an inductor is connected to a DC source. On connection, the rate of change of current is great and so a high back EMF is produced. What would have been an instantaneous jump in current is blunted by this effect. As the back EMF dies down, a steady state current flow is reached. 

Back EMF Draw an exponential decay curve (dotted) to show how back EMF is highest when rate of change of current flow is highest. This explains how inductors are used to filter out rapidly alternating current in clinical use. 

Mirkin and coworkers reported on catalytic molecular tweezers used in the asymmetric ring opening of cyclohexene oxide. In this case the early transition metal is the catalyst and rhodium functions as the structural inductor metal. The catalyst consists of two chromium salen complexes, the reaction is known to be bimetallic, and a switchable rhodium complex, using carbon monoxide as the switch. Indeed, when the salens are forced in dose proximity in the absence of CO the rate is twice as high and the effect is reversible [77]. 

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