8.5. Thermal diya strumu

8.5.2. Coefficient of brown dzherel strumu

Coefficient of brown dzherel strumu(KKD) often brown tightness due to total tightness of the strumu dzherel:

de P korisniy - korisna tightness of the strumum (tightness, which is seen in the old lance); P pov - povna tightness dzherela strumu:

P rep = P corisny + P vtrat,

tobto. total tightness, which is seen in the old lance (P coris) and in the neck of the struma (P vtrat).

Coefficient of coris de dzherel strumu (KKD) varies frequently core energy in view of the new energy that vibrates with the stem of the strum:

η = E correct E new ⋅ 100% ,

de E korisniy - korisna energy dzherela strumu (energy, which is seen in the old lance); E povna - povna energy dzherela strumu:

E surf \u003d E korisny + E vtrat,

tobto. the total energy that is seen at the old lance (E korisniy) and in the neck of the struma (E vtrat).

The energy of the dzherel strum is tied to the tension of the dzherel strum with the following formulas:

• the energy that is seen in the summer sky (corisna energy) for an hour t is connected with the cordial tension of the dzherel P

E corisny = P corisny t;

• the energy you see at Dzhereli Struma(energy of expenditures) per hour t is related to the intensity of expenditures of the dzherel P expenditures -

E cost = P cost t;

• The total energy that is vibrated by the neck of the struma in an hour t is tied up with the total tension of the neck P

E surf = P surf t.

The coeficient of coris di dzherel strumu (KKD) can vary:

• chastok, how to establish an opir of the ovnіshny lancer in the total support of the dzherel strumu and navantazhennya (ovnіshny lancer), -

η = R R + r ⋅ 100% ,

de R - opir lansyuga (navantage), to which it is connected to the struma; r - internal opir of the jerel struma;

• chastok, yaku to become potential difference on the terminals of the dzherel against the yogo electric shock force, -

η = U ℰ ⋅ 100% ,

de U - voltage on the clamp (cleme) dzherela struma; ℰ - ЕРС dzherela struma.

At maximum tightness, which is seen in the old lance, KKD dzherela struma is more expensive 50%:

to that, in this way, the opir vantazhennia R is stronger for the internal support r dzherela struma:

η * = R R + r ⋅ 100% = r r + r ⋅ 100% = r 2 r ⋅ 100% = 50%.

Butt 16. When connecting a jerela strum with a KKD of 75% to a deaky lansyug, a tension of 20 watts is seen on the new one. To know the amount of warmth that was seen at Dzherel Struma for the 10th century.

Solution. Let's analyze the mental tasks.

The tightness, which is seen in the old lance, is the chestnut:

P blue = 20 W,

de P corisnius - corisna tightness of the strum.

The amount of warmth that is seen at the neck of the struma is due to the intensity of the expenditure:

Q cost = P cost t,

de P vtrat - tightness of vtrat; t is the hour of roboti gerel strumu.

KKD dzherela pov'yazuє korisnu and povnu tightness:

η = P correct P new ⋅ 100% ,

de P povniy - povna tightness dzherela strum.

Korisna tightness and the tightness of the losses in the sum give the same tightness to the jerel strum:

P surf \u003d P korisny + P vtrat.

Records of equalization approve the equalization system:

η = P correction P renew ⋅ 100% , Q inflow = P inflow t , P recurrence = P correction + P intra. )

For the significance of the shukan value - the amount of heat that was seen in the jerelle Q of the inputs, it is necessary to indicate the intensity of the inputs P of the inputs. Vikonaemo substitution of the third equal to the first:

η \u003d P coryne P coryne + P int ⋅ 100%

i depending on P cost:

P cost = 100% − η η P cost.

Imagine taking the formula for virase Q int:

Q cost = 100% − η η P corisny t.

Rozrahuemo:

Q input = 100% − 75% 75% ⋅ 20 ⋅ 10 ⋅ 60 = 4.0 ⋅ 10 3 J = 4.0 kJ.

At the end of the day, 4.0 kJ of heat was seen at the jereli.

The tightness that develops as a strum dzherel in the whole lancer is called full strain.

Vaughn stands behind the formula

de P pro-povna tightness, which develops as a strum dzherel in the whole lance, Tue;

Her. d.s. dzherela, in;

I-value of the struma in lanceuzi, a.

At the infamous look, the electric lansyug is made up of the old house (navantazhennya) and of the support R that inner yard with a support R0(Opіr dzherela struma).

Replacing the magnitude of the E. f. with. through the voltages on the plots of the lansyug, we take it

Value UI indicative of tightness, which develops on the outer space of the lancet (navantage), and is called cinnamon tightness P sublog =UI.

Value U o I vydpovidaє natuzhnosti, yak gracefully stained in the middle of the dzherel, Її call intensification of expenses P o =U o I.

In this rank, the total tension is more expensive than the sum of the core tension and the tension of the P pro = P sublog + P 0.

The development of brown tension to full tightness, which develops with a dzherel, is called a coefficient of brown fat, shortened efficiency, and is indicated by η.

z

For all the minds, the coefficient of core di η ≤ 1.

How to express tightness through the size of the struma and the support

In such a rank, k.p.d. to lie down in the spіvvіdnoshennia between the internal support of the dzherel and the support of the spozhivach.

Sound the electric efficiency.

For practical electrical engineering, it is of particular interest to establish two sources:

1. Umova otrimannya the greatest coryne tightness

2. Umov otrimannya the largest k.p.

Umov’s treatment of the greatest chest tightness (tightness at the knee)

The electric strum develops the most significant tension (tension on the tension) in the same way, as the support of the tension is the support of the jerela stream.

The greatest tension is the same as half of all tension (50%) with the strum, which develops, in the whole lance.

Half of the tightness develops on the tension, while the other half develops on the internal support of the neck of the struma.

If we change the opir navantage, then the tightness that develops on the vanity will change, and the tightness that develops on the inner support of the nerve will increase.

If the opir vanishing is equal to zero, then the strum at the lanciug will be maximum, tse short circuit mode (short circuit) . May all the tension develops on the inner support of the struma. This regime is unsafe for Dzherel Strumu and for the entire Lanziug.

If we increase the opir of the tension, then the strum in the lance will change, the tightness of the tension will also change. With an arc of great support for the struma of the lancet, nothing was cleared up. This opir is called infinitely great. If the lancet is rozіknuto, then yogo opіr is infinitely great. This mode is called idle mode

In this way, in modes close to short flickering and idling, the core tension is small in the first wave for a small voltage wave, and in the other for a small struma wave.

Umov otrimannya of the largest k.p.

Coefficient of core pressure (k.p.d.) is 100% with an unfriendly move (in which case the core tension is not seen, but at the same time the tension of the dzherel is not seen).

In the world of increasing strumu, the efficiency of efficiency changes according to a straightforward law.

In the short-circuit mode, the efficiency is close to zero (there is no core tightness, and the tightness of the dzherel, which is developing, will be seen in the middle of the new one).

Pіdbivayuchi podbags vishchevyladennogo, you can zrobity vysnovki.

Mind control of maximum core tension (R=R 0) and mind control of maximum efficiency (R=∞) are not avoided. More than that, when otrimanny vіd dzherel maximum core tension (mode of narrowed tension), the efficiency becomes 50%, tobto. half of the tightness that develops, marvelously stained in the middle of the new.

In tight electrical installations, the mode of narrowed tension is unacceptable, which is why, under this, a marna vitrata of great strains is introduced. Therefore, for electric stations and substations, the modes of robotic generators, transformers, and rectifiers are designed in such a way as to ensure high efficiency (90% and more).

Also on the right in the technique of weak strums. Take, for example, a telephone. Under an hour, move in front of the microphone at the circuit of the device, an electric signal is generated at an intensity of about 2 mW. It is obvious that from the maximum distance of the connection, it is necessary to transmit a greater tension to the line of the yakomog, and that it is necessary to viconate the mode of the narrowed switching on of the navigation. What is the most important value for efficiency? Obviously, the shards of wasted energy are counted in parts or in units of a milliwatt.

Mode uzgodzhennogo navantazhennia zastosovuetsya at the radio equipment. In times, if the regime is not safe when the generator is connected without an intermediary connection, it is necessary to stop the use of these supports.

8.5. Thermal diya strumu

8.5.1. Tension dzherela strumu

Povna tightness dzherela strum:

P rep = P corisny + P vtrat,

de P corisny - corisna tightness, P corisnity \u003d I 2 R; P vtrat - tightness of vtrat, P vtrat \u003d I 2 r; I - the strength of the struma in the lance; R - opir navantage (starry lancet); r is the inner opir of the jerel struma.

Any tension can be covered for one of three formulas:

P real = I 2 (R + r), P real = ℰ 2 R + r, P real = I ℰ,

de ℰ - electrical disruption force (EPS) dzherela struma.

Korisna tightness- tse tightness, which is seen in the old lance, tobto. on navantage (resistors), and can be vikoristan for some purpose.

Core pressure can be covered for one of three formulas:

P korisn_st = I 2 R, P korisn_st = U 2 R, P korisn_st = IU,

de I - the power of the struma in the lance; U - voltage on the clamps (zatskach) dzherela struma; R – opіr navantage (starry lancer).

The tightness of the vrat is the tightness that one sees the strum, that is. at the inner lance, and stained on the process, which is the place at the very dzhereli; for some other purposes, the cost of spending cannot be beaten.

Excessive spending, as a rule, is covered by the formula

P cost \u003d I 2 r

de I - the power of the struma in the lance; r is the inner opir of the jerel struma.

With a short flicker, the contraction will turn to zero

P corisny = 0,

Shards of Opir Opportunity at the time of a short flicker during the day: R = 0.

Excessive tension with a short zamikanny dzherel zbigaetsya from the intensity of the costs and is calculated according to the formula

P pov \u003d ℰ 2 r,

de ℰ - electric shock force (EPS) dzherela struma; r is the inner opir of the jerel struma.

Korisna tension may maximum value at a glance if the opir navantage R is more durable for the internal support r dzherela struma:

R = r.

Maximum value of core tension:

P corishny max = 0.5 P refill,

de P povniy - povna tightness dzherel struma; P sur = ℰ 2/2 r.

Have a clear look formula for rozrahunku maximum core tightness looking like an approaching rank:

P corine max = ℰ 2 4 r .

For the forgiveness of the rozrakhunkiv, it is worth remembering two points:

• even though with two supports of the tension R 1 and R 2 of the lance, the same core tension is seen, then internal opir dzherela struma r is tied from the designated supports by the formula

r = R 1 R 2;

• If in Lanczyuz the maximum corisne tension is seen, then the strength of the struma I * in the Lanczyuz vdvіchі is less than the strength of the struma of the short chirp i:

I * = i 2.

Butt 15. When the battery of the elements flickers to the opir of 5.0 Ohm, it gives a strum with a power of 2.0 A. The short strum of the battery is 12 A.

Solution. Let's analyze the mental tasks.

1. When the battery is connected to the support R 1 = 5.0 Ohm, the lances flow with a power of I 1 = 2.0 A, as shown in fig. a , which is determined by Ohm's law for the full lanceg:

I 1 \u003d ℰ R 1 + r

de ℰ - EPC dzherela struma; r is the inner opir of the jerel struma.

2. When the battery flickers, a short flickering strum flows briefly in the lance, as shown in fig. b. The strength of the short strumu is determined by the formula

de i is the strength of the struma of a short flicker, i = 12 A.

3. When the battery is connected to the support R 2 \u003d r lance, the strum is flowing with the force I 2, as shown in fig. in , which is determined by Ohm's law for the full lancer:

I 2 \u003d ℰ R 2 + r \u003d ℰ 2 r;

at this point in lansy, the maximum corisna tightness is seen:

P corny max \u003d I 2 2 R 2 \u003d I 2 2 r.

In this way, for the expansion of the maximum core tension, it is necessary to determine the internal support of the strum r and the force of the strum I 2 .

To know the strength of the struma I 2, we write down the equalization system:

i \u003d ℰ r, I 2 \u003d ℰ 2 r)

and vikonaєmo podіl rivnyan:

i I 2 = 2.

Sounds are screaming:

I 2 \u003d i 2 \u003d 12 2 \u003d 6.0 A.

In order to know the internal opir of the dzherel r, we write down the system of equals:

I 1 \u003d ℰ R 1 + r, i \u003d ℰ r)

and vikonaєmo podіl rivnyan:

I 1 i = r R 1 + r.

Sounds are screaming:

r \u003d I 1 R 1 i - I 1 \u003d 2.0 ⋅ 5.0 12 - 2.0 \u003d 1.0 Ohm.

Razrahuyemo maximum korisnu tightness:

P corisny max \u003d I 2 2 r \u003d 6.0 2 ⋅ 1.0 \u003d 36 W.

Thus, the maximum pressure of the battery becomes 36 watts.

tightness- - [Ya.N.Luginsky, M.S.Fezi Zhilinska, Yu.S.Kabirov. English-Russian Dictionary of Electrical Engineering and Power Engineering, Moscow, 1999] Korisna Potuzhnіst Potuzhnіst (machine, possession, power unit or other technical building)…

Korisna tightness- Korisna potuzhnіst (Useful capacity) - potuzhnіst (machine, possession, energy unit or other technical annex), which is seen by the annex in the singing form for the singing method; drіvnyuє povnіy natuzhnosti for virahuvannyam vitrate. Economic and Mathematical Dictionary

tightness- 3.10 core tension: Effective tension at kilowatts, tested on a test bench on the shank of a crankshaft or chimney using the GOST R 41.85 method. Jerelo ... Glossary of terms for normative and technical documentation

tightness- Naudingoji galia statusas T sritis Standartizacija ir metrologija apibrėžtis Galia, susijusi su tam tikros sistemos, įrenginio, aparato ar įtaiso atliekamu naudingu darbu. atitikmenys: English netpower; useful power vok. Abgabeleistung, f;… … Penkiakalbis aiskinamasis metrologijos terminų žodynas

tightness- naudingoji galia statusas T sritis fizika atitikmenys: angl. netpower; useful power vok. Abgabeleistung, f; Nutzabgabe, f; Nutzleistung, f rus. Korisna tightness f pranc. puissance utile, f … Fizikos terminų žodynas

Stiffness, like you can get on the dvigun shaft; those that are effective. Great Radianska Encyclopedia

Korisna tightness- - tightness, which is seen by the attachment in the singing form and for singing. ST MEK 50(151) 78 ... Commercial electric power industry. Slovnik-dovidnik

pump pressure- Intensity, which is caused by the pump to a rare medium, which is supplied and depends on the fallow de Q pump flow, m3/s; P vice of the pump, Pa; QM: mass delivery of the pump, kg/s; LP corisna of the pump robot, J/kg; NP core pressure of the pump, W. [GOST… … Dovіdnik technical translation

corisna tightness (in motor transport tehnіtsі)- Korisna tuzhnistnost Potuzhnist, expressed in kіlovat, otrimana on test stand on the shank of the crankshaft or iogo equivalent that vymіryuєєy vіdpovіdno to the method viіrіvіvannya і і іn іtіzhnіstі, established by GOST R 41.24. [GOST R 41.49 2003] ... Dovіdnik technical translation

Korisna tightness in cotton wool- - [A.S. Goldberg. English-Russian Energy Dictionary. 2006] Topics energy industry EN watts out ... Dovіdnik technical translation

Let's take a look at the short circuits of the non-decoupled lances that add up to the resistor's struma.

We must follow the law of conservation of energy to the whole lance:

Points 1 and 2 for a closed lancet are omitted, the tension of electrical forces in a closed loop is equal to zero. Confidently asserting about the potency of the electric field of the post-strumum, about which it was already guessed earlier.

Father, at of a closed lancer, everything is warmly seen behind the windows of the robots of outside forces:, or , and mi again we come to Ohm's law, now for the closed loop: .

Again lanciugs call the tension of external forces, but there is a better thermal tension:

Korisniy name the thermal tension, which is seen in the old lancer (independently, if the crown is chidly in this particular weather):

The role of electrical forces in lanzugu. At the old lance, on the edge R, Electric forces are positive for the robot, and when the charge is moved in the middle, the struma is the same for the magnitude of the negative. The warmth of the old lance is seen from the help of the work of the electric field. To the robot, to the old lance, the electric field “turns” itself in the middle of the strum. As a result, all the heat in the lance is “paid for” by the robotic forces of the third party: the struma is consuming chemical (otherwise, even more) energy step by step. The electric field plays the role of a “courier”, which delivers energy to the outer lands.

Foliage of flat, coryne tensions and KKD in the support of tension R .

The number of fallows is taken from formulas (1 - 2) and Ohm's law for a full lance:

Graphs of these fallows you bachite a little.

Povna tightness monotonously changes over time, because the strength of the struma in the lances changes. Maximum total pressure seen when, then. at short flicker. Dzherelo strumu zdіysnyuє maximum robot for one hour, and then go to the heating of the dzherel itself. The maximum pressure is more

Korisna tension can have a maximum at (why you can change, taking a similar function (5) and equating it to zero). Substituting viraz (5), we know the maximum core tension.