The barring gear assembly also initiates rotation of the shaft during a startup phase prior to injection of steam in the steam turbine. The rotation speed of the shaft during turning phases is low and constant.
What is barring in compressor?
A barring engine (also called barring motor) is a small engine that forms part of the installation of a large engine , and is used to turn the main engine to a favourable position from which it can be started. ... Originally they were used to turn stationary steam engines to a position from which they could be started.
What is a barring device?
Engine barring devices are connected to engines . Known barring devices have been used to rotate crankshafts of engines and adding features to these known devices increases the complexity and cost of such devices. The subject barring device (10) includes a shaft (32) adapted for both axial and rotational movement.
What is barring in power plant?
Barring gear (or “turning gear”) is the mechanism provided to rotate the turbine generator shaft at a very low speed after unit stoppages . ... When it stops completely, there is a tendency for the turbine shaft to deflect or bend if allowed to remain in one position too long.
What is barring device for reciprocating compressor?
The barring device should be designed so that gas forces acting on the pistons cannot cause the compressor either to accelerate or to rotate in the reverse direction. With the barring device engaged, it should not be possible to start the compressor [6].
What is a turning gear?
marine. A reversible electric motor which, through a system of gears, can be used to turn slowly a large diesel engine or steam turbine and gearbox assembly. It enables precise positioning for overhaul or examination. The engaging and disengaging of the turning gear is accomplished by the lever.
What is turning gear in steam turbine?
The turning gear assembly typically consists of an electric motor connected to a set of reduction gears that mesh with a corresponding bull gear attached to the turbine rotor . The electric motor torque is converted to slow-speed rotation of the turbine rotor through a series of gear reductions.
Which gas cooling is used in large generator units of steam plant?
Many power generators over 150 MW in capacity utilize hydrogen as a cooling method to transfer heat from the power generating winding enclosure to the heat exchanges known as H2 coolers. Hydrogen cooled power generators are more efficient and have less mass of materials of construction than their air-cooled cousins.
Which type of gear mechanism is provided to rotate the turbine generator shaft?
A jacking gear (also known as a turning gear) is a device placed on the main shaft of an engine or the rotor of a turbine. The jacking gear rotates the shaft or rotor and associated machinery (such as reduction gears and main turbines), to ensure uniform cool-down.
What are 4 types of compressor capacity control?
Compressor capacity-control methods are utilized to maintain a required compressed gas delivery under variable process conditions. The main capacity control methods for reciprocating compressors are variable-speed drives, suction valve unloaders, step-less methods, clearance pockets and bypass recycling .
How do you control compressor discharge pressure?
The method comprising the steps of running a discharge pressure control routine, comprising the steps of: calculating the difference between the actual discharge pressure and a predetermined setpoint discharge pressure; computing the required change in valve position to achieve the setpoint discharge pressure, the ...
What is capacity of compressor?
Compressor capacity can be defined as the amount of air the unit is able to pump out . ... While a small and large compressor can have the same pressure capabilities, the larger model has a greater capacity to produce more compressed air. Capacity is expressed in terms of cubic feet per minute (CFM).
What are the arrangements of clutch and turning gears?
When the control lever is set for astern running, the control valve supplies oil pressure to the ring piston of the astern clutch. When either clutch is engaged, its pinion provides a drive to the large gear wheel of the driven shaft and the other pinion rotates freely .
How long should be a turning gear be operated?
In a single S109FB turbine shaft configuration, the time that the unit must remain in turning gear, at a minimum should be four hours , before the start if the shaft is stopped.
What is turning gear interlock?
Turning gear interlock is another important thing that prevents the admission of starting air to the engine cylinders when the turning gear is engaged . If the starting air is admitted with the turning gear engaged, then the turning gear along with the motor will fly off puncturing the bulkhead.
How long does it take to warm up a steam turbine?
They should be warmed up and cooled down slowly to minimize the differential expansion between the rotating blades and the stationary components. Large steam turbines may require approximately five to nine hours to warm up.
