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Section 6. Mechanical engineering
Akhmedov Khamidulla Abdukhoshimovich, Academy of sciences of the Republic of Uzbekistan Institute of mechanics and seismic stability of structures E-mail: [email protected]
ANALYSIS OF ENERGY INDICATORS OF THE SAW GIN WITH A NEW DESIGN
Abstract: The aim of the research is to find the law of frequency variation and uneven rotation of the rotor of electric motor, saw cylinder, throwing drum and the rotor barrel pulleys depending on the elastic-dissipative parameters of the belt drives, the moment of inertia of the electric motor, saw cylinder, throwing drum, the barrel drums of the feeder and the moment of resistance of the saw A cylinder, a throwing drum, and a pinch rollers of the feeder at different values using the equation of motion of the machine. In addition, it is necessary to establish ways to reduce the unevenness of rotation and the power consumption of the electric motor.
Keywords: saw gin, electric motor, saw cylinder, throwing drum, rib.
Ginning, in its strictest sense, refers to the process of separating cotton fibers from the seeds. The cotton gin has as its principal function the conversion of a field crop into a salable commodity. Thus, it is the bridge between cotton production and cotton manufacturing. Ginning is the first and most important mechanical process by which seed cotton is separated into lint (fiber) and seed and machine used for this separation is called as gin. It consists of two spirally grooved leather roller, two moving blades combined with seed grids called as beater assembly. During the ginning operation the shaft fails at certain location
In drawing up the differential equations of the feeder, we use the Lagrange equation of the second kind:
d_ dt
dT
M
dT dn 80
--+-+ ^ = Q[(],
d( d( 8(1),
(l)
of the belt drives H ■ m/rad; b1, b2, b, b4, b5 - coefficients of dissipation of belt gears, H ■m ■s/rad; ( , ( 2, ( 3, ( 4, ( 5 -angular velocities of the rotating masses of the system; c-1; i , i12, i13, i34, i35 - transmission ratios of belt gears.
The saw gin drive with a throwing drum and two drum feeders consists of belt gears. The following kinematic relations are valid for the drive:
¿D1 =<i)D /<1 = 2, ¿12 = 01 /02 = 2J, ¿13 = 01 /03 = 1,
¿34 =<M04 = ¿35 = 03 / 05 = 1737 (2)
For the generalized coordinates we take the angular velocities of the rotating masses of the feeder ( D ( , (2, (3, ( , ( . The kinetic energy of the drive has the following
form:
3
T — D
0D , 31 "012 , 32 ^
where T - is the kinetic energy of the system; n- is the potential energy of the system; 0 - is the dissipative function of the system; ( - generalized coordinate; ( - the generalized
speed; Q[(] - generalized force.
The dynamic model of the machine aggregate and the kinematic scheme are shown in (figure l), where 3D, 3P 32,33, 34,35, - respectively, the moments of inertia of the rotating masses, kt • m2; Md, M1, M2, M, M4, M5 -are, respectively, the driving torque of the electric motor and the moments of loads acting on the rotating shaft of the saw cylinder overlapping the drum, the intermediate shaft and the tumbling drum of the feeder H •m; c, c2, c3, c, c5 - the stiffness
+
; 2 2 33-032 34-042 35 *002
(3)
2 2 2 The potential energy of the feeder is a homogeneous quadratic form of the generalized coordinates and is written in the form
C1 • (0d -¿D1 -01)2 + c2 • (01 -¿12 -02)2 +
+C3 • (01 - ¿13 • 03 )2 + C4 • (03 - ¿34 • 04 )2 +
n = 1
2
+C5 • (03 - ¿35 0)2
(4)
Section 6. Mechanical engineering
The dissipative function of the system is expressed in the
form
0 = -• 2
61 • ((i>D - ¡D1 •faf + 62 ' ((i>1 - ¡12 -faf +
+ 63 • ((¡>i - ¡13 .(j>3Y + 6 4 • ((¡>3 - i3i •fa'faf +
+ 65 • (fa3 - ¡35
. (5)
Substituting certain terms, we obtain a system of differential equations of motion of the machine aggregate in a general form:
• (¡>D = MD - c1 •(<j)D -im • (j)l) - e1 •((¡>D -im • (j)l)
• ¡1 = C1 • iD1 • (<<D - iD1 • <j1) + 61 • iD1 • (4 - iD1 • <il) -
C 2 ^ <1 - i12 • <j2) - 62 • j1 - i12 • - C3 ^ <1 - i13 • <j3) -
- 63 • (<¡1 - iu • <¡3) - M1 (6)
• (¡¡2 = C 2 • i12 ^ <1 - i12 • <2) + 6 2 • i12 • - i12 • <^2) - M2 *3 • ¡3 = c3 • i13 • (<1 - i13 ■ <3) + 63 • i13 • (<¡1 - i13 • <>3) -
- C4 •(<3 - i34 • <4) - 64 • (<¡3 - i34 • <¡4) -
- C5 • (<3 - i35 • <5) - 65 •<3 - i35 • <k) - M 3
^4 • ¡4 = C4 • i34 • (<3 - i34 • <4) + 64 • i34 • (<¡3 - i34 • <¡4)- M4
^5 • ¡5 = C 5 • i35 • (<3 - i35 • <5) + 65 • i35 • ( 4 - i35 • 4 ) - M5
When examining engine aggregates, it is important to select the correct motor characteristics. At present, static, linearized dynamic, refined dynamic and dynamic mechanical characteristics of asynchronous electric motors are used. One of the most promising directions is an approximate consideration of the electromagnetic transients occurring in the engine and their mathematical description by a system of differential equations.
The system of nonlinear differential equations (5) and (6) has been studied on a computer, based on the results ofwhich the graphs of the change in the consumed power of the electric motor are plotted, depending on the following real parameters of the system (0,%): moment of resistance (M = 125.4629; M2 = 1.680576; M4 = 6.64 H •m - figure 2); elastic-dissipative parameters (c1 = 30700.06; c2 = 186.82; c3 = 204.85; c4 = c5 = =52.93 H m/ rad u 61 = 157.083; b2 = 0.662; b3 = 1.055; 6=6=0,188 H •m s/rad - figure 3) belt drive, moment of inertia of the electric motor (3D = 0.6 kg • m2), saw cylinder (31 = 0.37 kgm2),the throwing drum (32 = 0.013 kg•m2), the intermediate shaft (33 = 0.01 kg• m2), and the pin drums (34 =35 = 0.257 kg-m2 - figure 4) with a decrease (-100%) and an increase (100%) of the actual parameters.
The results of the analysis (Figures 1-2) shown, that with an increase in the resistance moment from -100 to + 100%, the power consumption of the electric motor of the saw cylinder, respectively, from 605.8 to 18448.1 W, the throwing drum from 9513.0 to 9627.0 W and the drum feeder barrel 9025.1 and 10115.0.
Figure 1. The graph of change of consumed capacity of the electric motor in dependence from the stiffness of the belt transfers cv c2, c3, c4,%
Figure 2. The graph of the change in the power consumption of the electric motor, depending on the moments of inertia of the electric motor 3D, the saw cylinder 31, the throwing drum 32 and the intermediate shaft 33 and the feed roll barrel 3., %
With an increase in the elastic-dissipative parameters of the belt transmission from -90 to -10%, the change in the power consumption of the electric motor is in the range of 9568-9584 W, and then remains constant with small deviations and amounts to 9567-9574 W.
With an increase in the moments of inertia of the electric motor rotor, the saw cylinder, the throwing drum and the drum barrel from -90 to 100%, the change in the power consumption of the electric motor is in the range 9562-9590 W.
References:
1. Mukhammadiev D. M. and e.g. Analysis of the static and dynamic characteristics of the saw cylinder of the fiber separator. "Problems of machine building and machine reliability".- Russia,- Moscow. 2009.- No. 2.- P. 13-17.
