How to undermine the active tension of the single-phase lancet of the snake struma. Active, reactive, flatulence in single-phase and triphasic lances

Rozberemo vpadok, if the generator has arrived at an appointment, what can be more active opir(Electric heating accessories, heating lamps). So, in this way, all the tension that is emitted by the generator, if the tension is active, then cos it's lonely.

Generator pressure active

P \u003d IU cos \u003d 200 1200 1 \u003d 240,000 W \u003d 240 kW.

Since we now have a switch on the generator, which can cos \u003d 0.8 (active and inductive opir), then the intensity is active, which is shown by the generator in the measure,

P = IU cos = 200 1200 0.8 = 192,000 W = 192 kW.

The generator of active tension will not be entangled, if you want a lot of strum 200, but to pass through the winding, heating it up. Increase the generator strum over 200, but it is not possible, as it is unsafe for the generator windings.

When navantage, scho maє cos = 0.5, the generator vіddaє active tension,

P \u003d IU cos \u003d 200 1200 0.5 \u003d 120,000 W \u003d 120 kW.

In this rank, mi bachimo, sho chim less cos may be slower, tim less active pressure on the generator, tim less vin will be occupied by active tension and tim less will be the coefficient of the core of the machine. It was conceivable to ward off active energy, taken by a slow-moving power plant, and reactive energy. To that, at the spare, which may be reactive, due to the installed electric heaters of active and reactive energy (their attachments and the robot are described in the fourteenth division of the book). At what is active that reactive energy for the status of active reactive tension can be assigned to the formulas:

Low "cosine fi" to direct:

1. To the extent necessary, reduce the total exhaustion of electrical stations and transformers.

3 formulas:

So, for example, if the pressure of the engine in the workshop is 80 kW, and the cost of the workshop is 0.8, then the pressure of the transformer for the life of the engine will be:

With a decrease in cos cost for the workshop to 0.6 for the same fatigue of the engines necessary tension there will be a transformer:

If the first type has a transformer of 100 kVA, then for the other type it is necessary to take a 180 kVA transformer for the pressure.

2. To reduce the coefficient of core power of generators and transformers. A generator or a transformer, which works on biasing with a low “cosine fi”, behind a strum can be biased, and on active bias. At the car, which works with undervoltage, the coefficient of power reduction falls, which leads to the loss of energy of the first engines (it is likely to peat or coal at thermal power stations, a rare fire in internal combustion engines).

3. Until the loss of tension and tension at the wires and the reduction of the cut of the wires. 3 formulas for the pressure of a single-phase snake struma

In this way, with the same and the same values ​​of tension, the change in voltage cos is accompanied by an increase in the struma of the droths and, also, an increase in the cost of heating (I 2 r). In order to avoid unsafe heating when the struma is increased, it is necessary to increase the struma. In addition, an increase in the struma in darts with a constant overshoot will lead to an increase in the voltage drop in them.

The value of active tension in the single-phase lance of the streak stream is determined by the formula P = UI cos fі, de U - priming voltage, V, I - priming strum, A, φ - phase zsuv between the elastic and strum.

It can be seen from the formula that the tension of the lance of a zminny struma can be known by an indirect method, by including three accessories: an ammeter, a voltmeter and a phase meter. But in this case, it is impossible to rely on the great accuracy of the reduction, because the error in the reduction of tightness is not only in the sum of the defects of all three outbuildings, but also in the error of the method of reduction, the switch on the ammeter and voltmeter. For this reason, this method can only be victorious at the tip, if the victorious precision is not required.

If the active tension must be accurately measured, then it is best to measure the wattmeters of the electrodynamic system or the electrical wattmeters. With rough measurements, ferrodynamic wattmeters can be blocked.

If the voltage in the lance is less than between the voltage of the wattmeter for the voltage, the strum is less than the allowable strum of the meter, then the circuit for connecting the wattmeter to the lance of the meter is similar to the circuit for including the wattmeter in the lance of the steady stream. So the strum coil is turned on in sequence with the voltage, and the voltage winding is parallel with the voltage.

With the connection of electrodynamic wattmeters, it was necessary to check whether the stench is polar in the pygmy lancet, and in the snake lancet struma. In order to ensure more correctly (on the scale) the insertion of the arrows I will attach to zero, the cob of windings on the panel will be marked with a dot or a star. Zatyskachi, marked with such a rank, are called generators, the shards themselves are connected to the energy supply.

The unbreakable coil of the wattmeter can be switched on according to the voltage ratings only with voltage streams of 10 - 20 A. If the voltage rating is greater, then the stream coil of the wattmeter is turned on through the voltage transformer.

To overcome the tightness of the lance of the snake struma with a low coefficient of tightness, a special low-cosine wattmeter should be used. On these scales it is indicated, for which the values ​​of cos and stink are transferred.

If cos fі I і \u003d 5 A, you can show more ventilation with strum I \u003d 5 A і cos fі \u003d 1 і with strum I \u003d 6.25 Aіcos fi \u003d 1 (so I \u003d I n / cos fі). The other type of wattmeter will have a change.

Inclusion of a wattmeter in the lancet of a strum, with a strum, the tension is greater than the allowable

If the strum voltage is greater than the permissible strum of the wattmeter, then the strum coil of the wattmeter is switched on through the strum transformer (Fig. 1, a).

Rice. Fig. 1. Schemes for connecting a wattmeter to a lance of a strum with a majestic strum (a) and a high-voltage gauge (b).

When choosing a transformer, the struma must be followed by the same, so that the nominal first strum of the transformer I 1 and add to the vimiruvanny strum in the measure, or more for the new one.

For example, if the value of the stream in the voltage reach is 20 A, you can take a stream transformer, the insurance for the first nominal stream is 20 A with a nominal transformation coefficient for the stream K н1 \u003d I 1 i / I 2 i \u003d 20/5 \u003d 4.

If the voltage in the vimiruvalny lance is less than the allowable wattmeter, then the coil of the voltage is turned on without intermediary to the tension voltage. The cob of the coil of tension behind the additional jumper / is connected to the cob of the strum coil. Also, the jumper 2 is installed obov'yazkovo (the cob of the cob is connected to the thread). Kіnets kotushki naprugi p_klyuchayut to іnshoy zatyskach merezhі.

To determine the real tightness of the twisted lance, it is necessary to multiply the wattmeter reading by the nominal transformation coefficient of the struma transformer: P \u003d Pw x K n 1 \u003d Pw x 4

If the strum at the railing can be changed to 20 A, then turn the strum transformer with the primary nominal strum 50 A, with chyom K n 1 = 50/5 = 10.

In this case, to determine the intensity of the pressure, the indication of the wattmeter should be multiplied by 10.

Vynachayut for the formula P = UI cos fі, de U - priymach voltage, B, I - strum priymach, A, φ - phase zsuv mizh prirugoyu and strum.

It can be seen from the formula that the tightness of the lance of the zminny struma can be determined by an indirect path, by including three accessories: an ammeter, a voltmeter i. However, in this way it is not possible to rely on the great accuracy of the reduction, so the error in the reduction of the tightness is not only due to the sum of the defects of all three devices, but also to the method of measurement, viklikana by the method of turning on the voltmeter and ammeter. That is why this method can be zastosovuvat only at a glance, if the accuracy of vimiriv is not required.

If the active tension needs to be accurately measured, then it is best to stop the wattmeters of the electrodynamic system or electronic wattmeters. With rough vibrations, there may be more victorious ferrodynamic wattmeters.

If the voltage in the lance is less than between the wattmeter's lanyard for the voltage, the strum is less than the allowable strum of the wattmeter, then the scheme for including the wattmeter in the lance of the wattmeter is similar. So the strum coil is switched on sequentially with the voltage, and the voltage winding is parallel to the voltage.

With the connection of electrodynamic wattmeters, it was necessary to check whether the stench is polar in the fast-bearing lancet, and in the serpentine lancet strum. In order to ensure more correctly (on the scale) the insertion of the arrows I will attach to zero, the cob of windings on the panel will be marked with a dot or a star. Zatyskachi, marked with such a rank, are called generators, the shards themselves are connected to the energy supply.

The unbreakable coil of the wattmeter can be switched on sequentially with voltage only at voltage streams of 10 - 20 A. If the stream of voltage is greater, then the stream coil of the wattmeter is turned on through a vimiryuvalny stream transformer.

To reduce the tightness of the lance of the snake strum with a low coefficient of tightness, special low-cosine wattmeters should be used. On the scales it is indicated, for which the values ​​of cos and stink are recognized.

If cos fі I і \u003d 5 A, you can show more ventilation with strum I \u003d 5 A і cos fі \u003d 1 і with strum I \u003d 6.25 Aіcos fi \u003d 1 (so I \u003d I n / cos fі). For another person, the wattmeter will be overwhelmed.

Inclusion of a wattmeter in the lancet of a strum, with a strum, the tension is greater than the allowable

If the strum voltage is greater than the permissible strum of the wattmeter, then the strum coil of the wattmeter is switched on through the strum transformer (Fig. 1, a).

Rice. 1. Schemes of including a wattmeter in the lancet of a zminny strum great strum(a) the one at the high-voltage wire (b).

When choosing a transformer, the struma must be followed by the same, so that the nominal first strum of the transformer I 1 and add to the vimiruvanny strum in the measure, or more for the new one.

For example, if the value of the stream in the voltage reach is 20 A, then you can take a stream transformer, the insurance for the first nominal stream is 20 A with a nominal stream transformation coefficient K n1 \u003d I 1 i / I 2 i \u003d 20/5 \u003d 4.

If the voltage is less than that allowed by the wattmeter, then the coil of the voltage is turned on without intermediary to the tension voltage. The cob of the coil of tension behind the additional jumper / is connected to the cob of the strum coil. Also, the jumper 2 is installed obov'yazkovo (the cob of the cob is connected to the thread). Kіnets kotushki naprugi p_klyuchayut to іnshoy zatyskach merezhі.

For the purpose of denoting the functional tension in a vimiruvanny lancet, it is necessary to multiply the wattmeter reading by the nominal transformation coefficient of the struma transformer: P \u003d Pw x K n 1 \u003d Pw x 4

If the strum at the edge can be changed to 20 A, then turn the strum transformer with the primary rated strum 50 A, with K n 1 \u003d 50/5 \u003d 10.

In which case, to determine the pressure value, the wattmeter indication must be multiplied by 10.