<h2 class="rich_media_title" > what is the best switch for a slag pot with 30KW? </h2>
(Circle cards have been added here, please check out the today's headlines client)
<h2 class="rich_media_title">
</h2>
Little charge said electricity today
Since the power supply level is not stated, it is temporarily identified as a 380V slag pot, and it is not understood whether it is an inductive load or a resistive load, and it is considered to be a perceptual load for the time being, so let's make an analysis of this problem.
< h1 class= "rich_media_title" > calculation of the operating current</h1>
Phase line current calculation method:
Formula I=P÷ (U×1.732×cosΦ) according to the three-phase electrical phase line current
P-power (W); U-voltage (380V); cosΦ- power factor (0.8 due to inductive load); I-phase line current (A);
Bring in data P=30kw, U=380V;
The phase line current is calculated to be I=57A
Calculated that the current is 56A, because in the actual work also to consider the starting current, in the selection of the switch when the rated current should be greater than the calculation of the current between 1.2 times and 1.5 times, the switch current to take 68A.
< h1 class="rich_media_title" > the calculation of the cable diameter</h1>
Calculate the working current of the load, according to the current value can further calculate the diameter of the cable required, the calculation law can be based on the corresponding table in the following figure, 68A to choose the cable diameter is about 16 square three-core copper core wire, some people think that 10 square is enough, but ten square long or long distance transmission will have voltage loss, the line heat is more severe.
< h1 class="rich_media_title" > the choice of switch</h1>
Above we have calculated the capacity of the switch, about 68A, so when choosing it is recommended to use 80A air switch as the main power switch, if you also need to use AC contactor control, it is also recommended to choose 80A AC contactor, economically allow the choice of 100A is also OK.
< h1 class="rich_media_title" > summary</h1>
Because I don't know what kind of equipment the slag pot is, let's take the 380V inductive load as the calculation, the above is the calculation result, the cable selects 16 square three-core copper core wire, and the switch selects 100 amp AC contactor or 80 amp air switch.