Determining an engine's load is a fundamental skill for industrial electricians, engineers and many other professionals. As with most mathematics, formulas exist to help simplify this process. Using these formulas, all one must do is "plug in" variables and perform basic math operations to solve the problem, or in this case, determine a motor's load with efficiency already known. The process is quite easy and relatively quick.
Instructions
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1
Record the rated horse power from the exterior of the motor or its documentation.
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2
Note the efficiency at full rated load.
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3
Use the following equation:
Input Power @ full rated load (kW) = Rated HP * (0.7457/Efficiency @ full-rated load)
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4
Measure and note the 3-phase power with an electrical meter.
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5
Use the following formula:
Load = (Measured 3-Phase Power in kW/Input Power @ full rated load) * 100%