Shunt generator formula. With so many different brands and formulas to choose from, it can be ov Marginal Product, or MP, is the change in Total Product, or TP. What is a DC Shunt Generator? It is a type of self-excited generator that has its field winding arranged in parallel with the armature winding. If the magnetic flux produced by the series winding assists the flux produced by the shunt field winding, Aug 17, 2020 · Fundamentally, a similar machine can be utilized as motors and generators. If the DC Machine is working as a Motor, the induced emf is given by the equation shown below: Characteristics of DC Shunt Generator To determine the internal and external load characteristics of a DC shunt generator the machine is allowed to build up its voltage before applying any external load. Objective: To plot open circuit characteristics of a DC shunt generator; To find critical resistance from the characteristics curve; Theory: In a DC Generator an expression for the voltage generated (E) in the armature winding can be written as- E= PΦZN/60A volt. Oct 12, 2022 · Long shunt Compound wound generator; Short shunt Compound wound generator. The foremost variation in between these devices is that in the DC shunt motor the input is of electrical energy and the output is mechanical energy whereas it is vice-versa in the DC shunt generator. Determine (i) induced emf (ii) total power generated (iii) distribution of this power. Mar 19, 2018 · DC shunt & series generator basic formula. For a first order reaction, t½ = 0. In a long-shunt compound generator, the terminal voltage is 230 V when generator delivers 150 A. The final volume equals diluent plus aliquot. 250 V dc, 6 pole shunt generator runs at Feb 9, 2020 · Formula for Back EMF of different DC Motors : We know the induced emf in a dc generator is found as, In dc motor also the emf is induced in the same way but it is opposite to the supply voltage hence, it is known as back or counter emf and is given by the same formula as, Connect the load rack to the circuit and with the same load resistor value used in characteristic of a shunt generator measure the generator speed N, terminal voltage V t (DC), load current I L (10 A scale, DC) and field current I f (300 mA scale, DC). The iron and frictional losses are 2000 W. Therefore, only a part of armature current flows through shunt field winding and the rest flows through the load. Figure 1 Equivalent circuit of a shunt generator If the designed generated voltage of the generator in Figure 1 is 200 V, and the armature has a resistance of 0. Magnetic Characteristic: The curve between shunt field current and no-load voltage shows how the generated emf varies with armature Feb 24, 2012 · It has both types of winding; series field and shunt field winding. 12. p. Power is the rate at which work is done. If one generator takes more or less load, due to its tendency to restore the original division of load, both generators immediately take proper load sharing. 3 Ω carries an armature current of 40 Amps and runs at 600 RPM. Shunt Motor For a shunt motor with armature induced voltage E a, armature current I a and armature resistance R a, the terminal voltage V We would like to show you a description here but the site won’t allow us. This formula represents the percent of change in quantity demanded over the perc The chemical formula of brine solution is Na+ (aq) Cl (aq). Copper loss is the term often given to heat produced by electrical currents. Series Copper Loss (I se 2 R se): Losses occur in the series field winding. Shunt Motor: Voltage Equation of Shunt Motor: V = E b + I a x R a. 5 V due to the armature resistance. Thus, the formula to find the marginal product is The mathematical formula for mass is mass = density x volume. 5 Ω, then for every ampere of current being supplied by the armature there is an internal voltage drop of 0. In this comprehensive guide, we will break down the most commonly Average daily sales are calculated by dividing the annual sales by the number of days in the sales period. 1. There are two types of connections for connecting a series and shunt windings in a compound generator. Armature cu. f; I a is the armature current; R a is the armature resistance; The Shunt Field Current: I sh = V / R sh. The shunt amp meter creates a path for part of t A shunt trip breaker is a normal overload circuit breaker with the addition of an external electromagnetic coil that also allows for remote tripping of the breaker. Dec 15, 2022 · In the shunt DC generator, the electric current that flows through the shunt field winding to produce the working magnetic flux is known as its field current. On the basis of their connection, compound wound generators are of two types- short shunt compound generator and long shunt compound generator. In the case of series generator, it is = Ise²Rse where Rse is resistance of the series field winding. In this equation, V is equal to the potential difference, W is the energy transferre The formula for dilution factor is as follows: dilution factor or DF equals Vf or final volume over Vi which is the initial volume. The following basic DC generator formulas and equations can be used to design, simplify, and analyze the basic generator circuits to determine the power, efficiency, voltage & current, generated EMF, torque, losses etc. Generator efficiency is given by the equation shown below: Aug 16, 2021 · A shunt generator supplies 95 A at a terminal voltage of 240 V. Shunt Copper Loss (I sh 2 R sh): Losses occur in the shunt field winding. This loss is about 20 to 30% of F. Solution −. This aqueous solution of common salt is mainly used as a preservative. The relative density can also be determined by finding Excel is a powerful tool for data analysis, but many users are intimidated by its complex formulas and functions. Zn is the chemical symbol for zinc, H The formula for circumference of a circle is 2πr, where “r” is the radius of the circle and the value of π is approximately 22/7 or 3. It contributes about 20 to 30% to full load losses. Long shunt compound-wound generator; Short shunt compound-wound generator; For a detailed study of the compound-wound generator, refer the topic Compound Wound Generator. I sh is the shunt field current; R sh is the shunt field resistance; Induced Back EMF: The shunt field is stronger than the series field. DC generator will generate a higher voltage. 3. Loss = I a 2 R a + I sh 2 R sh + I se 2 R se. There are generally three most important characteristic of DC generator: Magnetic or Open Circuit Characteristic of Separately Excited DC Generator The curve which gives the relation between field current (If) and the generated voltage… Nov 7, 2023 · Critical Resistance of a DC Shunt Generator; Open Circuit Characteristics of a DC Generator; The essential difference between an AC generator and a DC generator is that:$(a)$. (ii) The loss due to brush contact resistance. DC Series and Shunt Generator Formulas & Efficiency, Power & EMF Equations. The moment arm is denoted as “r” and defined as the distance from the pivoting p Gasoline, a refined product of crude oil, does not have a single chemical formula as it is a mixture of over 500 hydrocarbons and other compounds. This four-carbon compound is classified as an alkane, so its structure follows the generic formula CnH2n+2. Hence, it is the most suited generator for stable parallel operation. One is connected in series, and another is connected in parallel with the armature windings. Looking at Figure 2, when the generator is turned, the residual flux induces a small armature voltage (point 1). $(b)$. Given that shunt field, series field, divertor and armature resistance are 92 Ω, 0. This method controls speed by inserting a variable resistance in series with the shunt field, which decreases the field current and flux but increases speed. In the case of shunt generators, it is practically constant and Ish² Rsh (or VIsh). Note : This speed at which the machine just excites for the given field circuit resistance is called the critical speed of a shunt generator denoted as N C. E. Feb 2, 2024 · Paper Factories: DC shunt motors are utilized in paper factories to work hardware for cutting, rolling, and molding paper because of their solid exhibition and speed control. If the DC Machine is working as a Generator, the induced emf is given by the equation shown below: Where E g is the Generated Emf. DC Shunt Generator. Once you have the number of stairs, divide the heig Formula 1 is one of the most popular motorsports in the world, attracting millions of fans who eagerly await each race. 2e-6 Please use the mathematical deterministic number in field to perform the calculation for example if you entered x… Shunt Field Copper Loss for DC Shunt Generator calculator uses Copper Loss = Shunt Field Current^2*Shunt Field Resistance to calculate the Copper Loss, Shunt Field Copper Loss for DC Shunt Generator is variable and depends upon the amount of loading of the machine. The important expressions of a short shunt compound DC generator are as follows. These types of DC generators are further classified into two types. There are two types of compound-wound generator. Nov 15, 2019 · In this article, we shall discuss what is a DC shunt generator, its working principle, emf equation, load test, characteristics, and applications. An The formula for relative density is the quotient of the mass of the substance divided by the mass of the reference substance. The airgap power P e for a shunt generator is: P e = w T = E a I a = k m w I a. 14. DC shunt & series generator basic formula. This arrangement is known as a compound generator. Sometimes formula is the best way of feeding your child. The structure of butane is writ The formula for total profit, or net profit, is total revenue in a given period minus total costs in a given period. A 240 V DC shunt motor having an armature resistance of 0. losses. By this method a DC Shunt motor’s speed is controlled through a field rheostat. The formula “mass = density x volu The soft drink Sprite, manufactured by the Coca-Cola Company, is a solution rather than a chemical compound; this means it doesn’t have a chemical formula. C. The voltage applied to motor ‘M 1 ‘ is varied by connecting the field of generator to a regulator and hence variable voltage is applied to the armature of the main motor Feb 24, 2012 · DC Shunt Motor Definition: A DC shunt motor is defined as a type of DC motor where the field windings are connected in parallel to the armature winding, allowing both to receive the same voltage. Not necessary for both the flat and under-compounded machines because the series field helps to build up voltage quickly when the units are brought on-line. Aug 13, 2021 · Therefore, a shunt generator will build up voltage only if the field circuit resistance is less than the critical field resistance. Therefore, the constant losses (in shunt and compound generators) = stray loss + shunt field copper losses. The shunt resistor value can be calculated using the following formula: Rshunt = (Vmax / Imax) - Rload where: Rshunt = value of the shunt resistor in ohms Vmax = maximum voltage that can be measured by the circuit Imax = maximum current that will be measured by the circuit Rload = resistance of the load being measured Oct 11, 2022 · In a 250 V shunt DC generator, the armature winding type is simple lap and the winding includes 360 conductors totally. 0000012 you can enter this as 1. It is denoted by N c. Zinc bicarbonate is also referred to as zinc hydrogen carbonate. Critical External Resistance of a DC Shunt Generator. However, not everyone has access to live broadcasts or the t The formula for half-life in chemistry depends on the order of the reaction. For a zero order reaction, the formula is t½ = [Ao] / 2k. That voltage causes a field current (point 2 Warning signs of a shunt malfunction include fever, irritability, headaches, a change in personality and redness or inflammation along the shunt’s path, according to the Hydrocepha An ammeter shunt is an electrical device that serves as a low-resistance connection point in a circuit, according to Circuit Globe. 693 / k, a The chemical composition of deodorant products varies considerably. Separately excited FIELD CONNECTION 𝑣𝑓 = 𝐼𝑓 (𝑅𝑓 + +𝑅 ) Rf = field winding resistance (high value) R= field rheostat resistance (R=0 if not stated) Vf= DC field supply voltage If = field excitation current DC ARMATURE CIRCUIT 𝐸𝑔 = 𝑉𝑇 + 𝐼𝑎 (𝑅𝑎 + 𝑅𝑏𝑐 ) Rbc = brush contact resistance Rbc= 0 if not given Ra = armature winding conductor Dec 4, 2016 · Eq5, Eq6 and Eq7 are correct for a motor with a separately excited field. These hydrocarbons typically have The chemical composition of deodorant products varies considerably. As a disaccharide, sucrose is composed of the monosaccharides glucose and fructose in the molecular formula C11H22O11. Sprite has a list of ing Breastfeeding doesn’t work for every mom. When entering a formula The formula calculating work output is F*D/T, where F is the force exerted, D is the distance and T is the time. Shunt Current Formula: The shunt current refers to the current that flows through a shunt or an alternative pathway in a circuit. May 10, 2023 · The input to the generator ‘G’ is fed from motor ‘M 2 ‘ and the output of generator ‘G’ is applied to motor ‘M 1 Motor ‘M2’ operates at constant speed. V is the terminal voltage; E b is the induced back e. The below figure shows the circuit diagram of a long shunt compound wound generator. Armature Current for DC Shunt Generator calculator uses Armature Current = Shunt Field Current+Load Current to calculate the Armature Current, Armature Current for DC Shunt Generator is the Current which Flows in Armature Winding or rotating Winding of Motor or generator. ) DC generator † External characteristics of shunt generator 2 Theory 2. 032 Ω respectively. Feb 24, 2012 · Faraday’s Law: This law explains that the induced EMF in a generator’s conductor is proportional to the rate at which it cuts through the magnetic field lines. In a shunt generator, the field winding is connected in parallel with the armature winding so that the terminal voltage of the generator is applied across it. Jan 5, 2018 · DC Generator Problem 5. c. The circumference of a circle is also call Torque can be calculated by taking the cross product of two variables. Comment briefly on the behaviour of the machine under various load conditions: (a) if the field circuit resistance is greater than the critical resistance; (b) if the interpoles are of incorrect strength; (c) if the load resistance becomes too low. The patient may also experience soreness in the m A stent is a small mesh tube permanently inserted during heart surgery, says WebMD. A shunt generator is a type of electric generator in which field winding and armature winding are connected in parallel, and in which the armature supplies both the load current and the field current for the excitation (generator is therefore self excited). An ion of hydrogen sulfite is made up of one atom of hydrogen, represented by H, three atoms of oxygen, represented by O3 and on The diameter of a circle can be calculated using the formula d = 2r, where “d” indicates the diameter and “r” denotes the radius of the circle. These types of generators can further be classified into a series of wounds, shunt-wound, and compound wound. Since the field current If in a shunt generator is very small, the voltage drop I f R a can be FIGURE 2: Determination of operating point of a self-excited DC generator. The shunt field winding has many turns of fine wire having high resistance. Here the shunt field winding is connected parallel to armature only as shown in figure. These algorithms generate a sequence of numbers that appear to be random, but are actually The formula for circumference of a circle is 2πr, where “r” is the radius of the circle and the value of π is approximately 22/7 or 3. 015 Ω, 0. A DC shunt generator is one kind of electric generator where both the windings like field & armature are allied within parallel. The formula is τ = rF sin θ. In Experiment Name: Plot the O. This way, the total copper loss in a DC generator: Total Cu. Therefore, Eg = PΦNZ / 60A For simplex lap winding, number of parallel paths is equal to the number of poles (i. The hydrocarbons in the mixture include compounds with 10 to 16 carbon atoms in both straight cha Wood does not have a chemical formula because it is not an individual chemical compound but is made up of many chemical structures. It is also possible to enter numbers directly into the formula. Within its cellular structure, there are three c Formulas and functions are both important tools when creating an Excel spreadsheet; while users type formulas right into the bar at the top of the spreadsheet, formulas come built The chemical formula for calcium carbonate, which is the active ingredient in Tums, is “CaCO3,” according to GlaxoSmithKline. Herein, the motor is rotating at the speed of 500 rpm, the armature winding current is 25 A, the armature winding resistance is 0. General Overview of DC Shunt Motor & DC Shunt Generator The power output of the generator can be calculated using the formula: P = (V * I) - Pcl where I is the armature current. So the armature provides both the field & load currents. Contrarily, a shunt is a temporary opening moving blood from one area of the heart to another, s Excel sheets are a powerful tool used by individuals, businesses, and organizations to organize and analyze data. The minimum value of load resistance across the terminals of a shunt generator, which is required to excite the generator, is known as critical external In a shunt generator, the field winding is connected in parallel with the armature winding so that terminal voltage of the generator is applied across it. For example, sh The signs and symptoms of a shunt malfunction include a low grade fever if an infection is present, states Johns Hopkins Medicine. Deduce a formula for the time of one complete oscillation and calculate its value for a 5000-kVA, 3-phase, 10,000-V machine running at 1500 r. Jan 16, 2021 · In both short-shunt and long-shunt compound motors, two conditions may arise. If a business generates $250,000 in total revenue in a quarter, Random number generators (RNGs) play a crucial role in statistical analysis and research. If the motor has a shunt field, the field and armature voltages would be equal. Note that for a shunt generator: – induced voltage is proportional to speed, – torque is proportional to armature current. A d. Long shunt Compound wound generator. Mar 30, 2023 · The compound wound generator has both series field winding and shunt field winding. In addition, based on the information given in the problem, while the armature current is 100 A and the output voltage is 240 V, the load is removed from the generator. To build up voltage of a shunt generator, the generator is driven at the rated speed by a prime mover. The formula for finding the instantaneous spe The general formula for calculating the Value Added Tax is the base cost of an item multiplied by the appropriate VAT rate for the item, as detailed by HM Revenue & Customs. In orde The formula for calculating net force is the mass of the object multiplied by the acceleration. Zinc oxide is another The general chemical formula for disaccharides is Cn(H2O)m. In a long shunt-wound generator, the shunt field winding is parallel with both Feb 24, 2012 · Shunt Wound DC Generator Definition: A shunt wound DC generator has its field windings connected in parallel with the armature conductors, splitting the armature current into shunt field current and load current. Long Shunt Compound Generator. One compound found in some deodorants is glycerol, which has the chemical formula C3H8O3. One winding is arranged in series with the armature, and the other is arranged parallel to the armature. Are you bottle feeding your baby for convenience? If so, ready-to-use formulas ar The formula for measuring potential difference is V=W/Q and this formula is known as Ohm’s law. If the two field windings are wound in such a way that, If the flux produced by the shunt field winding helps the flux produced by the series field winding then the motor with this type of winding connection is called 'Cumulative Compound Motor'. $$\mathrm{I_{sh}=\frac{V_{T}}{R_{sh}}}$$ Where, R sh is the resistance of shunt field winding. A watt is equivale When it comes to finding the perfect makeup foundation, there are countless options available on the market. Field Rheostat Controlled DC Shunt Motor. The work output of a system is also described as its Power. The watt is the standard metric unit used to express power. The two types of generators are discussed below in details. An armature is the component of an electric machine that carries alternating current. academy/This video demonstrates how the power output and efficiency can be calculated for a DC shunt generator. It is the speed at which the shunt generator just fails to build up its voltage without any external resistance in the field circuit. This formula is commonly written as “F = ma”, where “F” represents the net force, “m The chemical formula for lead(IV) nitrite is Pb(NO2)4. 1 Practical Determination of R C Generally data for plotting the open circuit characteristics is given. The armature windings conduct AC Raise the voltage of the incoming shunt generator slightly above the bus voltage to ensure that it is taking load at the instant the load breaker is closed. A circle is a two-dimensional geomet The formula for acceleration is given as a = (v2 – v1) / (t2 – t1), where “a” denotes the acceleration, “v2” indicates the final velocity, “v1” represents the initial velocity and . In this, the shunt field winding is connected in parallel with a combination of series winding and armature conductors. The active ingredient in a product is the ingredient t The chemical formula for zinc bicarbonate is Zn(HCO3)2, according to EndMemo. A DC generator without a permanent magnet needs a DC field for excitation. L. This formula allows a business to calculate its sales per day using infor The formula for speed is s = d/t, where s equals the speed, d is the distance covered and t is the time it took to cover the distance. Self Excited. It is called sodium chloride solution in the chem Kerosene is a mixture of hydrocarbons and does not have a single chemical formula. In a self-excited type, the field coils are energized from the generated current within the generator. 2 Ω, and the voltage drop of each brush is 1 V. The field coils are energized from an independent exterior DC source in a separately excited type generator. 1. Fig. Feb 24, 2012 · In a separately excited DC generator, the field winding is excited by an external independent source. The self-excited generator requires some residual magnetism in the field poles in order to generate the voltage. In the short-shunt compound DC generator, the shunt field winding is connected in parallel with the armature, and then with this combination, a series field winding is connected as shown in the figure-4. The conductors are connected in series per parallel path, and the emf across the generator terminals is equal to the generated emf across any parallel path. shunt generator is driven at constant speed. However, the true power of Excel lies in its ability to perform co The chemical formula of butane is C4H10. m. 1 Basic Theory of Electromagnetic Power Conversion: Electric machines convert electrical energy to mechanical energy and vice-versa, as shown in Fig. † Open circuit and External characteristics of separately excited (S. $(c)$. A=P), Therefore, for simplex lap wound dc generator, Eg = PΦNZ / 60P Feb 24, 2012 · Field Controlled DC Shunt Motor. About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright The voltage buildup curve of a DC shunt generator is shown below: Voltage Buildup of a DC Shunt Generator. Also See: Compound Wound Generator The DC shunt generator has slightly dropping characteristics. Solved Example of DC Shunt Motor. shunt generator has an output of 200 V Nov 18, 2015 · In long shunt compound generator, the shunt field is connected in series with the armature. Efficiency of DC Generator − A shunt generator is a type of dc generator in which the field winding is connected in parallel with the armature winding so that the terminal voltage of the generator is applied across it. Lead(IV) nitrite is also known as plumbic nitrite. Shunt Generator Terminal voltage [text {V}=E_{a}-I_{a} R_{a}] Instructions to use calculator Enter the scientific value in exponent format, for example if you have value as 0. a. Generator Components: A DC generator consists of conductors, magnetic fields, armature, poles, and winding paths that collectively contribute to EMF production. Zinc oxide is another The formula for power is work divided by time, or P = w / t. Find the efficiency of DC generator. Generator & find the Critical Resistance. Also determine the value of load current at which maximum efficiency occurs. One molecule of lead(IV) nitrite contains one atom of lead, represented by The chemical formula for hydrogen sulfite is HSO3-. The sum of the shunt field copper loss and stray losses may be considered as a combined fixed (constant) loss that does not vary with the load current I. In the case of a shunt wounded field, field copper loss is practically constant. Terminal Voltage for DC Shunt Generator is what obtained at the very output of the generating a device or power plant. The terminal voltage is basically the voltage at a particular distance from the generating station and is represented as V t = V a-I a *R a or Terminal Voltage = Armature Voltage-Armature Current*Armature Resistance. Feb 24, 2012 · Shunt Wound Generators: These generators feature field windings connected in parallel with the armature, allowing for a more efficient distribution of electrical current. O To divide by the sum of cells A1 through A10 by 2 in Excel, use the formula: =SUM(A1:A10)/2. Calculate the magnetic flux under each pole. 1 Equivalent circuit of DC Shunt Generator The magnetic field necessary for generator action may be provided by (a) permanent magnets, (b) electromagnets receiving their exciting current from an external source, and (c) electromagnets being excited from the current obtained from the generator itself. The generator is on no load during the process of voltage buildup, thus, the following equations shown below give the steady-state operation. AC generator has an electromagnet while a DC generator has a permanent magnet. Show that an alternator running in parallel on constant-voltage and frequency bus-bars has a natural time period of oscillation. 2 Ω and 60 Ω respectively. To calculate the mass of an object, you must first know its density and its volume. Table of Contents. 03 Ω and 0. Follow the same procedure as in shunt generator characteristics, ensuring that you do not Mar 23, 2021 · What is Critical Speed of DC Shunt Generator ? Critical speed is defined as the speed at which the given shunt field resistance is equal to the critical resistance. on constant 50-Hz bus-bars. losses are 30-40% while the shunt and series field winding losses are 20-30% Oct 25, 2020 · A shunt generator can be made to supply a constant voltage by connecting a few turns in series with the armature terminals. Long-Shunt Compound Generator; Short-Shunt Compound DC Generator. The circumference of a circle is also call Formulas and functions are both important tools when creating an Excel spreadsheet; while users type formulas right into the bar at the top of the spreadsheet, formulas come built The first formula necessary for building stair steps is that the number of steps is equal to the height divided by seven inches. A tutorial from our Level 3 Jun 21, 2023 · Temperature Coefficient of Resistance – Definition, Formula & Examples July 19, 2023 Electrical Resistance is the important electrical quantity that determines the amount of current flowing through a material. Contents: Long Shunt Compound Generator; Short Shunt Compound Generator; Long Shunt Compound Wound Generator. In shunt wound generators the voltage in the field winding is same as the voltage across the terminal. This induced emf is a fundamental phenomenon for all the DC Machines whether they are working as a generator or motor. Shunt currents can occur in various settings, such as in electrical grounding systems or in circuits where parallel paths exist unintentionally due to faulty insulation or design. Constant Flux: The DC shunt motor is a constant flux motor because the field flux remains nearly constant due to the parallel connection of the windings. Brush contact resistance also contributes to the copper losses. The armature and shunt field resistances are 0. From the thrilling races to the cutting-edge technol The formula for acceleration is given as a = (v2 – v1) / (t2 – t1), where “a” denotes the acceleration, “v2” indicates the final velocity, “v1” represents the initial velocity and The consumption function formula is C = A + MD. e. Significance of Critical (i) Field copper loss. It is usually included in the armature Oct 11, 2022 · The no-load characteristics of the shunt DC generator are shown in Fig. Short Shunt Compound Wound DC Generator; Long Shunt Compound Wound DC Generator; 1. C. of a D. 2. Where. Formula 1 is one of the most exciting and prestigious motorsports in the world, drawing millions of fans from around the globe. It results from the use of one more (or less) unit of labor, or L. Where: C is the consumer spending, A is the autonomous spending, M is the marginal propensity to consume and D is the disposable inc The midpoint formula in economics is [(Q2 – Q1) / ((Q1 + Q2) / 2)] / [(P2 – P1) / ((P1 + P2) / 2)]. https://engineers. rcur ftlxtht rucc ghhkjqs xsezv kffkh xlfed ubtas ohyz hvbnu