4.8 Turning Gear and Speed Reducer
4.8.1 Inspection and installation of gear reducer or worm wheel set gearbox shall comply with the following provisions:
1 The gearbox and base plate shall have at least locating pins at diagonal line positions，and the locating pins and pin holes shall be in close contact.
2 The gearbox horizontal joint surfaces shall be in close contact，and after tightening the bolts，there shall be no gap when checked with a 0.05mm feeler gauge.
3 When the gearbox is enclosed，the joint surfaces shall be applied with oil-resistant sealing coating material.If gasket should be added，the material of the gasket shall be oil resistant.
4.8.2 The lubricating device of reducer and worm wheel set shall comply with the following provisions:
1 The oil spray pipes of lubricating device shall be purged before assembling，the assembling shall be secure and reliable，oil spray nozzles shall be directed to gear engaging part，and all oil circuits and holes shall be clean and well through.
2 For lubricating devices with oil being directly carried by gears，the oil level meter indication shall comply with design requirements and agree with true oil level，and in operation with normal oil level，the lowest tooth of the lowest gear shall be submerged.
4.8.3 Inspection and installation of reducer gears shall comply with the following provisions:
1 Gears shall have no crack，porosity or damage，and the surface shall be smooth in appearance check.
2 Mutually engaged gears with common divisor shall have stamp marks.
3 When a dial gauge is used to measure the reducer gear side gap，one gear in the pair shall be fixed and the other be rotated in the measurement，and the gap should be 5%of the gear modulus or comply with the specifications in Table 4.8.3.
Table 4.8.3 Tooth side clearance of reducer（mm）
Note:It shall be center distance for cylindrical gears and standard pitch cone generatrix length for bevel gears.
4 The teeth engagement print in a coloring check shall be flat and straight，with a width not less than 65%of tooth height and a length not less than 75%of tooth length，the color shall be coated homogeneously.
5 The gear ratio of reducer shall be noted in the installation records.
4.8.4 Inspection and installation of worm wheel sets shall comply with the following provisions:
1 The worm and worm wheel shall have no crack，porosity or damage，and the tooth surface shall be smooth in appearance check.
2 The worm wheel set teeth engagement shall be checked by a coloring check，print shall be present in the middle of each tooth working surface，and the print shall have a length not less than 65%of tooth length and a height not less than 60%of tooth height，the color shall be coated homogeneously.
3 For a multi-head worm，color shall be coated at each head for check one by one，and the contact position of each head on worm wheel teeth shall be the same.
4 The tooth side clearance of worm wheel set shall be checked with a dial gauge and shall comply with the specification in Table 4.8.4:
Table 4.8.4 Tooth side clearance of worm wheel set（mm）
5 The play value of a worm wheel set of the governing device should be 0.15mm-0.20mm.
6 Each tooth of worm wheel on oil inlet side shall have an oil receiving groove.
7 The worm wheel set driven by a synchronizer motor shall rotate flexibly and steadily，and the lubrication shall be good.
8 The worm wheel set ratio shall be recorded.
4.8.5 The inspection and installation of reducer and worm wheel set bearings shall comply with the provisions in 9.2.10-9.2.17 of this part.The clearance and tightening force of bearings and type of rolling bearings shall be recorded.
4.8.6 The adjustment and trimming of reducer and worm wheel set shall comply with the following provisions:
1 When the center distance and tooth tip clearance both meet the standard，if the tooth side clearance is too small and it is not possible to adjust the center distance，the non-working surface of the gear or wheel teeth shall be trimmed.
2 Corresponding correction values shall be reserved for position change due to temperature and loading direction in operation for reducer or worm wheel set.
4.8.7 Inspection and installation of turbine turning gear shall comply with the following provisions:
1 The gears and worm wheels shall comply with the provisions of 4.8.1-4.8.6.
2 The mounting position of turning gear shall meet the normal operation requirements for rotor under cold and hot conditions；the coupling guard shall be mounted to ensure that the rotor will not touch the guard after thermal expansion.
3 The oil sealing device for shaft and operation rod penetrating the casing shall be free of leakage.
4 The horizontal and vertical joint surfaces of turning gear shall have no gap when checked with a 0.05mm feeler gauge.
5 The manual manipulation of turning gear shall be flexible.After the turbine rotor is rolled，the turning gear shall be able to automatically disengaged from the turbine rotor，the manipulating rod shall be locked automatically after disengagement，and the installation direction of interlock device for oil inlet valve and handle shall comply with requirements on drawings.
6 All bolts and fasteners inside the turning gear shall be locked.
7 Oil resisting gaskets and coating materials shall be used for turning gear.
8 The centering for motor coupling of turning gear shall comply with the provision in 9.2.22 of this part.
9 A guard shall be provided for turning gear motor coupling.