Losses Gearbox

The turbogenerator speed must be maintained within narrow limits if it is to generate power acceptably and the control system must be capable of preventing over-speed upon sudden loss of load. For this latter requirement, fastacting valves are necessary with full modulation within 0.5 s. The security of the turbine is also dependent upon the lubrication of its bearings, and it will be found that the control systems are closely linked with the various lubricating systems (turbine, gearbox and alternator). 

An electric motor of efficiency 0.92 and a manual 1-speed transmission have been used for all the simulations. The transmission often constitutes a significant loss factor, and losses in using 5-speed or automatic transmissions (Cuddy, 1998) are higher than for the 1-speed gearbox. Because the actual Lupo 3L has n electronically operated automatic transmission with higher efficiency than the corresponding manual transmission, the 1-speed model was selected in order to avoid a distorting impact on the simulation results. 

Basic engine, no losses for inlet or exhanst systems, no losses for gearbox and mechanical transmission. 

Pi = the electrical power at the terminals of the generator (the generator losses and gearbox losses can be ignored). 

The losses between the gearbox input shaft and the electrical terminals of the generator... 

From (2.33) and allowing for the losses in the gearbox and generator, the overall thermal efficiency rjpao can be found as follows. 

P is the impeller power requirement, i.e it represents the rate of energy dissipation within the liquid. The electrical power required to drive the motor will exceed P by the motor, gearbox, and bearing losses. 

It must be borne in mind that the power requirement which is calculated from power curves gives a measure of the energy dissipated within the liquid. It does not give any indication of whether or not this power is dissipated effectively. Furthermore, it does not contain the losses which occur in the motor/gearbox/ bearings which must be considered in sizing the drive unit. 

First, select the appropriate agitator and decide the speed of rotation N, calculate Reynolds number and determine Po from the Po-Re graph. This defines the power P that the agitator has to deliver to the liquid select the next size motor P to allow for losses in the gearbox, seals and bearings. 

Next, find the power P of the next standard motor that will deliver the required power P allowing for losses in the gearbox, bearings and seals. Set the shaft natural frequency/ such that the shaft speed N is 70% ofi.e. 

Elimination of the main drives gearboxes Higher rehabihty and availability Lower downtime for maintenance and breakdowns Higher annual production with the same conveyor Decreased revenue losses... 

Propulsion Shaft orooeller Gearbox seizure Loss of thrust Loss of speed Yes Anchor 1 4 3 12... 

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