Here are the answers to the March 31, 2022 edition of TPO's Exam Study Guide:

Under normal operating conditions, what is the maximum acceptable current imbalance?

The answer to this question is C, 5%. Voltage imbalance is a major cause of motor failures (especially in lift stations). In three-phase systems, it is important to understand the phase-to-phase voltage will not be equal, and slight differences in voltage will cause much larger current imbalances and will shorten the lifetime of insulation and cause motor overheating. The maximum recommended current imbalance between the legs should never exceed 5% under normal operational conditions according to NEMA Standards MGI-14.35. Another cause of voltage imbalance can be loose connections or high-resistance contacts. For safety reasons always get assistance from a qualified electrician when working around electrical systems.

Aluminum sulfate reacts with alkalinity to form insoluble floc. Which reaction indicates a balanced chemical reaction?

The correct answer is D. Treatment plant operators are sometimes challenged to identify a chemical reaction or identify a balanced chemical reaction when taking upper level certification exams. One method of correctly identifying a balanced chemical reaction is to break down the number of single elements on each side. The chemical reaction is balanced, if the elements on the left side equal the elements on the right side.


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