CN201629078U - Falling action tester receiving electromagnetic damping - Google Patents

Abstract

The utility model relates to a falling action tester receiving electromagnetic damping which comprises a base, a stud, a photoelectric detector, a nonferrous metal tube, a photoelectric detecting platform, a signal collecting socket, a zero-point locking pin, a timing display, and a sandwich type composite magnetic body used for testing. The sandwich type composite magnetic body includes magnetic steel and a nonferrous medium ring; two pieces of magnetic steel are sucked together by being spaced by the nonferrous medium ring. The stud is fixed on the base; the photoelectric detector is fixed on the stud; the nonferrous metal tube is respectively punched with a pair of holes in a certain distance; the zero-point locking pin is arranged on the zero-point part of the nonferrous metal tube; and the timing display is connected with the signal collecting socket. The falling action tester receiving electromagnetic damping can detect the speed, travel formula and damping coefficients of a falling magnet and visually explain the influences of electromagnetic damping phenomenon from data; in addition, the falling action tester receiving electromagnetic damping can very conveniently change the quality of the magnet so as to change the damping coefficients and implement measurement for a plurality of times. The falling action tester receiving electromagnetic damping is simple to be operated, is visual and effective, and has accurate experimental data.

Description

Be subjected to the falling experiment instrument of electromagnetic damping

Technical field

The utility model relates to a kind of physics educational apparatus, especially falls to being subjected to the analysis to measure instrument of electromagnetic damping motion situation relevant in the non iron metal tube with magnet.

Background technology

When closed conductor and magnet generation relative motion, can produce electromagnetic resistance between the two, hinder relative motion, this phenomenon becomes the electromagnetic damping phenomenon.(Lenz law) can explain this phenomenon with Lenz law, when magnetic flux changes in the closed conductor, the magnetic field that the induction current that produces in the loop produces always stops the variation of magnetic flux, can hinder both relative motions, its resistance size is proportional to physical quantitys such as the magnetic induction density, speed of related movement of magnet.When magnet falls, be subjected to the electromagnetic damping that induction current produces on the tube wall, thereby the magnet movement situation is different fully with freely falling body in the non iron metal tube.

The more existing experimental apparatus that is used for physics teaching only can be demonstrated the phenomenon that is subjected to electromagnetic damping when magnet falls and makes bradykinesia qualitatively, though these experiments can allow magnet fall respectively to comparing in different tubes of material with the plain metal piece, but be confined to observe qualitatively different motion conditions, can not measure speed and distance in the magnet dropping process quantitatively.

Summary of the invention

The purpose of this utility model is to overcome above problem, can reflect objectively that magnet also can be analyzed quantitatively in the speed of different damping condition lower magnet whereabouts and the relation of distance by the electromagnetic damping phenomenon of tube wall induction current generation when falling in the non iron metal tube.

The utility model comprises base (1), pillar (2), photodetector (3), non iron metal tube (4), photodetection platform (5), signals collecting socket (6), lock pin at zero point (7), timing display (8), the sandwich built-up magnet (9) that is used to test.

Pillar (2) is fixed on the base (1), photodetection platform (5) is fixed on the pillar (2), non iron metal tube (4) is upward pressed certain distance, and each beats pair of holes, lock pin at zero point (7) places place, non iron metal tube (4) hole at last zero point, photodetector (3) is fixed on punching place that photodetection platform (5) is gone up and placed non iron metal tube (4), and timing display (8) is connected on the signals collecting socket (6).

Sandwich built-up magnet (9) comprises magnet steel (10), non iron dielectric ring (11), and two magnet steel (10) are pulled together across non iron dielectric ring (11).

For quantitative measurment goes out speed and distance in the magnet dropping process, the technical scheme that the utility model is taked is:

(1) select the non iron metal tube of a 70cm, in the upper end following 8cm place along diametric(al) beat pair of holes as zero point and the zero point of adding lock pin, below zero point 2.5,5,10,15,25,35, each beats pair of holes the 55cm place, photogate is installed as measurement point at place, the every pair of hole, measures the instantaneous velocity whenever pointed out and from zero point to time that this point is experienced, but just verifying speed formula and distance formula, and try to achieve ratio of damping β and limiting velocity v _TFor eliminating the edge effect influence of the non iron metal tube mouth of pipe, non iron metal tube hole at 4 last zero point place is provided with lock pin 7 at zero point, null position is chosen in the following 8cm of upper end mouth of pipe place, and with a pair of removable pin falling bodies is locked in zero point, and falling bodies were fallen with zero initial velocity from zero point.

(2) quality and the ratio of damping in order to change magnet easily becomes magnet design " sandwich built-up magnet ", i.e. across a non-ferromagnetic dielectric ring and mutual two blocks of oblate cylindricality magnet steel of adhesive.Change the internal diameter of dielectric ring, or in ring, fill the tin grain, can change the quality of falling bodies.Fill the tin grain in the dielectric ring, it is more even that falling body quality is distributed.

(3) in the signal acquisition circuit, clock signal produces the 1ms pulse signal, and the number of gate signal control wave is carried out timing by 4073 with door, is presented on the LED charactron by display chip then.It is 1ms that time precision requires, and the speed when non iron metal tube total length 70cm, magnet reach state at the uniform velocity is 0.1m/s approximately, and display design is four.

The utility model compared with prior art has the following advantages: except being subjected to the slow phenomenon in electromagnetic damping whereabouts by the qualitative observation magnet, can also quantitatively measure speed, distance formula and the ratio of damping of whereabouts magnet, the influence of electromagnetic damping phenomenon is described on the data intuitively; In addition, can change the quality of magnet easily, take multiple measurements thereby change ratio of damping.Reasonable in design, simple to operate, effectively directly perceived, experimental data is accurate.

Description of drawings

Fig. 1 is the utility model structural drawing that " is subjected to the falling experiment instrument of electromagnetic damping ";

Fig. 2 is the whereabouts synoptic diagram of magnet in the non iron metal tube;

Fig. 3 is " sandwich built-up magnet " structural drawing and sectional view;

Fig. 4 is the timing circuit entire block diagram;

Fig. 5 is that the magnet height is 1.980cm, and quality is the experimental result of 25.75g;

Fig. 6 is that the magnet height is 1.980cm, and quality is the experimental result of 29.20g.

Embodiment

Below in conjunction with specific embodiments and the drawings, the utility model is described in further detail.

The utility model comprises base (1), pillar (2), photodetector (3), non iron metal tube (4), photodetection platform (5), signals collecting socket (6), lock pin at zero point (7), timing display (8), the sandwich built-up magnet (9) that is used to test.Sandwich built-up magnet (9) comprises magnet steel (10), non iron dielectric ring (11), and two magnet steel (10) are pulled together across non iron dielectric ring (11).

Testing used non iron metal pipe range is 70cm, and its external diameter is 26mm, and wall thickness is 2mm; Base is long to be 270mm, and wide is 190mm; Column is long to be 735mm; Platform is long to be 170mm, and wide is 45mm; Testing used non iron dielectric ring diameter is 20mm, and wall thickness is 2mm; The magnet steel diameter is 5mm.

Change ratio of damping β with the method that changes falling body quality m, under the different damping condition, record the relation of y～t and v～y.Verify the speed formula and the distance formula of being derived with this, operating process is as follows:

(a) according to Fig. 1 each parts is connected, photodetector places acquisition mode;

(b) select non iron dielectric ring (11) among Fig. 3, two magnet steel adhesives are formed falling bodies;

(c) falling bodies are placed the non iron metal tube (4) of Fig. 1, and pin falling bodies with lock pin at zero point (7);

(d) pull up lock pin at zero point (7), falling bodies are fallen, repeatedly measure the fall time t of zero point respectively, and average to each sensing point.

(e) repeatedly measure each falling bodies elapsed time Δ t of sensing point place respectively, and average.

(f) according to the t that is surveyed, Δ t, and the parameter of falling bodies self, calculate the relation of distance and time y～t and speed and time v～t.

Be subjected to the magnet falling speed formula of electromagnetic damping to be

v＝v _T(1-e ^-βt)

V in the formula _TBe limiting velocity, β is a ratio of damping.

The distance formula that magnet falls is

$y=v_{T}t-\frac{v_T}{\mathrm{\β}}(1-e^{-\mathrm{\βt}})$

Embodiment 1:

The built-up magnet interlayer, h=9.80mm, total length l=1.980cm, both ends of the surface magnetic B=270mT, gravity acceleration g=9.794m/s ², quality m=25.75g,

Measure y ~ t relation

y(cm)	2.50	5.00	10.00	15.00	25.00	35.00	55.00
								t(s)	157.8	312	621.8	924.8	1536.4	2147.6	3405
t 1(s)	157	314	623	925	1536	2152	3398
								t 2(s)	158	311	624	923	1540	2150	3401
t 3(s)	157	310	622	927	1534	2147	3407
								t 4(s)	159	311	621	924	1532	2145	3408
t 5(s)	158	314	619	925	1540	2144	3411

Measure v ~ y and concern (instantaneous velocity)

Measure v ~ t relation

t(s)	157.8	312	621.8	924.8	1536.4	2147.6	3405
								v(cm/s)	15.916	16.071	16.071	16.019	16.418	17.838	18.199

V ~ t and y ~ t relation curve as shown in Figure 5, ratio of damping β=53.82s ^-1

Embodiment 2:

The built-up magnet interlayer, h=9.80mm, total length l=1.980cm, both ends of the surface magnetic B=270mT, gravity acceleration g=9.794m/s ², in interlayer, add tin grain, quality m ₂=29.20g,

Measure y ~ t relation

y(cm)	2.50	5.00	10.00	15.00	25.00	35.00	55.00
								t(s)	137.8	264.2	524.6	789.2	1317	1847.4	2887.6
t 1(s)	137	264	525	790	1319	1850	2894
								t 2(s)	138	262	524	788	1319	1841	2885
t 3(s)	137	264	525	791	1316	1852	2880
								t 4(s)	139	266	523	793	1310	1844	2882
t 5(s)	138	265	526	784	1321	1851	2897

Measure v ~ y and concern (instantaneous velocity)

Measure v ~ t relation

t(s)	137.8	264.2	524.6	789.2	1317	1847.4	2887.6
								v(cm/s)	19.604	20.497	20.539	20.842	20.497	20.497	21.019

V ~ t and y ~ t relation curve as shown in Figure 6, ratio of damping β=46.59s ^-1

The circuit that can verify this instrument by above embodiment satisfies measurement requirement, and experimental implementation is easy, the accurate readability of DATA REASONING; V ~ the t that records in the experiment is consistent with theoretical formula with the relation of y ~ t; Can record limiting velocity vT and calculate ratio of damping β, be consistent, reach the effect that the electromagnetic damping phenomenon that produces in the experiment is carried out quantitative measurment with theoretical formula.

Claims (6)

1. falling experiment instrument that is subjected to electromagnetic damping, it comprises base (1), pillar (2), non iron metal tube (4) is characterized in that: it also comprises the sandwich built-up magnet (9) that is used to test; Pillar (2) is fixed on the base (1), and following 8cm beats pair of holes as zero point along diametric(al) in the place to non iron metal tube (4) in the upper end, and zero point is following 2.5,5,10,15,25,35, and each beats pair of holes the 55cm place.

2. the falling experiment instrument that is subjected to electromagnetic damping according to claim 1, it is characterized in that: it also comprises sandwich built-up magnet (9), form by magnet steel (10) and non iron dielectric ring (11), two blocks of magnet steel (10) are pulled together across non iron dielectric ring (11), can fill the tin grain in the dielectric ring and change quality.

3. the falling experiment instrument that is subjected to electromagnetic damping according to claim 1, it is characterized in that: non iron metal tube (4) also comprises lock pin at zero point (7), null position places place, non iron metal tube (4) hole at last zero point, and with a pair of removable pin falling bodies is locked in zero point.

4. the falling experiment instrument that is subjected to electromagnetic damping according to claim 1 is characterized in that: it also comprises photodetection platform (5), and photodetection platform (5) is fixed on the pillar (2).

5.The falling experiment instrument that is subjected to electromagnetic damping according to claim 1 is characterized in that: it also comprises signals collecting socket (6), and signals collecting socket (6) is fixed on the base (1).

6. the falling experiment instrument that is subjected to electromagnetic damping according to claim 1 is characterized in that: it also comprises timing display (8), and timing display (8) is connected on the signals collecting socket (6).

7. the falling experiment instrument that is subjected to electromagnetic damping according to claim 4, it is characterized in that: described photodetection platform (5), it also comprises photodetector (3), and photodetector (3) is fixed on punching place that photodetection platform (5) is gone up and placed non iron metal tube (4).

Images