Question

What are the logic’s adopted in barring gear motor? 

Answer 1

For start permission

a) Local or remote start. 

b) JOP is running. 

c) Motor hand barring is permissive. 

d) 42 contactor in MCC is off. 

e) Turbine speed is <100 rpm. 

Start permission (42S of MCC) 

a) All above 

b) Bearing oil pressure is >0.35 kg/ cm² . 

c) No thermal over load of 42S. 

d) No one-DG condition. 

Start permission (42 of MCC) 

a) Start permissive of 42S. 

b) Barring gear engage or motor speed reached to 1475 rpm. 

c) Turbine speed is <100 rpm. 

d) Bearing oil pressure is >0.35 kg/ cm² . 

e) No thermal over load of 42. f) No one-DG condition.