8.5.1 Hand barring arrangement
Should the ETG be unavailable, provision is made to turn the rotors manually by mounting a lever and fulcrum apparatus at a prearranged point on the cover of a bearing pedestal. This lever operates on a permanent toothed-wheel between two turbine rotors (Fig 1.125). This is usually an operational feature to protect the turbine in a heat-soaked condition.
Further hand barring, for maintenance purposes only, can often be carried out by using a simple crowbar against a toothed barring ring, replacing the normal spacing ring between rotor couplings, and levering against a simple fulcrum plate secured to the pedestal horizontal joint face (Fig 1.126).
