Content articles will help exploit and commissioning staff alone make the chart currents, moments and county efforts needed to solve specific problems.
Ropeway drive motor for overcoming the circumferential force on the driving pulley during the movement of the rolling stock and associated moving masses: the head and tail ropes and the diverting pulleys and tension, etc. Depending on the route profile, loading direction and mutual arrangement rolling magnitude and sign circumferential force on the drive pulley varies widely. When the positive force of the motor in a power running mode, negative — in the brake. A particularly large range of change of district efforts on passenger pendulum cableways. The changes occur several times a day. So, on cable cars, designed to deliver vacationers to the beach resorts and back in the morning, passengers tend to down to the sea, and for dinner — in the opposite direction. In walking the roads, delivering passengers to the mountains, the behavior of the opposite district efforts.
Limit values of the positive efforts of the district acquired when lifting a fully loaded wagon on the steepest part of the track when another car empty. A marginal negative values occur at the same site, when fully loaded wagon when empty other moves in the opposite direction. All other possible values the efforts of the district are located in this interval.
The drive motor, of course, should provide job indefinitely ropeway in one or the other limiting mode. Therefore, to select the parameters of the engine management system and the design of the road is made by calculation charting district efforts in basic modes of the cable car.
This work is quite skilled and time-consuming. Run its operational forces, and personnel adjustment is hardly possible. Meanwhile, the need may arise. In the process of installation and long-term operation cableway it may change the parameters of the individual elements of the components of the road: cars, cables, motors and so on. And the project materials are often lost. So, of all the cable cars Crimea chart district efforts preserved only by cable car, «Mishor — Ai-Petri» in Yalta.
We have developed and tested technique of charting district efforts by practical measurements of armature current of the drive motor.
Based on the technique of the direct dependence of developing a DC motor electromagnetic torque M from the current I.
Both of these values are usually unknown. We only know that their product accurately CF can be considered the same in all operating modes of the engine, including in the nominal mode. Thus, the value of Kf can be determined from nominal data output:
Motor rated current Ir is given his passport, and the rated torque Mn can be determined by the rest of the passport.
Driving transfer torque on the winding circle is shown in Fig. 1. Torque is transmitted through the mechanical device consisting of a gear with a gear ratio p, couplings, shafts and bearings. On the drive pulley is not transmitted all the time by the engine. Part of it is spent on overcoming the forces of friction in mechanical gears. Accounting for them is quite complicated, and there has to rely on the technical literature cited in the averaged data. The total efficiency of the mechanical transmission to drive fur pendulum ropeway with two-stage gearbox can be considered approximately equal to 0.8. The brake mode when the forces are transmitted from the drive pulley to the engine, some of them also lost in the mechanical transmission.
Therefore, the engine does not have to resist the whole time on the drive pulley, and a few of his lesser magnitude. Accordingly decreases and the motor current.
Direct proportionality between developing motor torque and current in its anchor allows the district to replace charting effort Charting currents. Recalculating the current of each point of such a diagram in the corresponding time diagram obtained points. Knowing the radius of the drive pulley, the chart points easily turn into a chart of district efforts. Each of these three charts is an intrinsic value in dealing with specific issues. Thus, according to the chart, you can determine the actual current loading of the engine, to calculate the mean — square current. When selecting the gearbox may need to chart points. Efforts in traction ropes defined by the diagram of district efforts.
Made by the two boundary currents charts done two full haul wagons at low speed throughout the route. One of the wagons fully loaded, the second — empty. On the drive pulley is put noticeable mark and mark the passage of a certain fixed point is recorded current motor armature. Thus, the number of points in the diagram of currents will correspond to the number of revolutions of the drive pulley for the period of motion. Recording currents produced for the two directions of movement of wagons, ie the ascent and descent of the estimated cost.
During measuring the current engine from cars in different points of the route of its value may be positive or negative. Positive current means that the engine has to overcome the impact of the drive pulley rolling stock plus the force of friction in mechanical gears, which means it operates in the power mode. According to the measured current developed by them to determine the moment M = kFI. On the drive pulley will be passed this time, increased gear, ie kFI p. But part of it will be spent on overcoming the resistance of mechanical gears. Thus, the torque on the shaft of the drive pulley be Mw = p kFI fur.
Knowing the radius of the drive pulley Rsh is possible to determine the force on the circumference of the winding.
Negative current means that the drive motor is necessary to restrain the desire to increase the rolling speed of the moving masses, and it works in braking mode. But the impact of losses in mechanical gears is somewhat different. They facilitate the task of the engine and reduce its current in braking mode. The moment on the drive pulley FshRsh, reduced by gear ratio p and by mechanical losses, must balance the torque of the motor.
Thus, the formula for calculating the District effort at low currents, the engine remains the same, but the rate of fur moved from the numerator to the denominator.
Considered a way of charting the currents of the drive motors has been tested on a pendulum suspended passenger ropeway «Miskhor — Ai-Petri.»
Experimental method of charting the measured values of the currents are much easier to design organizations used the settlement.
It could easily be performed by the operating personnel or adjustment. The estimated values of the motor current value of district efforts to more accurately reflect the state of the electrical and mechanical equipment. Maximum reliability of the data is achieved with a current excitation drive motor is equal to the nominal, and in the measurement of the armature current devices must be sufficiently accurate.
Among other things, changing charts county effort over time represents the change in condition of the equipment the cable car. Therefore charting county efforts should be encouraged during the annual INSTALLATION.