4. a) Explain what is meant by the term single phasing.(5)
(b) Explain the probable effect of single phasing on a delta connected squirrel cage induction motor on 75% full load.(5)
(c) State a method by which a motor can be protected against the effects of single phasing.
(6)
Reference Answer
### (a) Explanation of Single Phasing Single phasing is a fault condition in a three-phase electrical system where one of the three supply lines (or phases) to a piece of equipment, such as an induction motor, becomes open-circuited. The equipment, designed to operate on a balanced three-phase supply, is now forced to operate on only two phases. **Key Characteristics and Causes:** * **Loss of a Phase:** The fundamental issue is the complete loss of voltage and current flow in one of the three conductors (e.g., L1, L2, or L3).
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