Exam Question
Describe with the aid of a diagram the operation of the following components of electrical equipment and explain the purpose of each. (16)
(a) under voltage protection;
(b) miniature circuit breakers;
(c) reverse power tripping.
Class 4 (4th Engineer)
MET
📅 Aug 2025
Reference Answer
### (a) Under Voltage Protection
**1. Purpose:**
The primary purpose of under-voltage protection is to ensure personnel and equipment safety. It is designed to automatically disconnect a circuit or piece of machinery when the supply voltage falls below a pre-determined, safe operational level. Its key functions are:
* **Personnel Safety:** To prevent the automatic and unexpected restarting of machinery (e.g., lathes, drill presses, large motors) upon restoration of power after a blackout. This prevents injury to operators who may be working on or near the machine, assuming it is de-energized.
**1. Purpose:**
The primary purpose of under-voltage protection is to ensure personnel and equipment safety. It is designed to automatically disconnect a circuit or piece of machinery when the supply voltage falls below a pre-determined, safe operational level. Its key functions are:
* **Personnel Safety:** To prevent the automatic and unexpected restarting of machinery (e.g., lathes, drill presses, large motors) upon restoration of power after a blackout. This prevents injury to operators who may be working on or near the machine, assuming it is de-energized.
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