Exam Question
(a) Explain why a purifier is not attaining its rated speed on starting from rest? (8)
(b) How do you select the appropriate Gravity disc of a Purifier? Why is this selection an important element in the purifier operation? (8)
Class 4 (4th Engineer)
MEP
📅 Oct 2025
Reference Answer
### (a) Reasons a Purifier Fails to Attain its Rated Speed from Rest
A purifier's failure to achieve its rated rotational speed (typically 6,000-10,000 RPM) from a standstill is a critical issue indicating excessive opposing torque that the electric motor cannot overcome. A systematic investigation is required, categorizing the potential faults into mechanical, electrical, and operational causes.
#### 1. Mechanical Causes
These faults increase the frictional resistance within the purifier assembly.
A purifier's failure to achieve its rated rotational speed (typically 6,000-10,000 RPM) from a standstill is a critical issue indicating excessive opposing torque that the electric motor cannot overcome. A systematic investigation is required, categorizing the potential faults into mechanical, electrical, and operational causes.
#### 1. Mechanical Causes
These faults increase the frictional resistance within the purifier assembly.
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