Power factor Definition and 126 Threads

Please have a look at the following links: http://www.eaton.com/ecm/groups/public/@pub/@electrical/documents/content/sa02607001e.pdf (Table 3) http://www.electrical-installation.org/enwiki/Power_factor_correction_of_induction_motors FigL24) - For power factor correction, why would the...

Hi, I did a lot of googling and tried to search every forum I could, but I didn't quite found what I was looking for. Sorry if this has been asked before, english isn't my first language so there's a chance that I used wrong words to search for this question. Also I'm not sure if you use...

Homework Statement A small industry operates from 220 volts supplied by a utility. The small industry represents a load to the utility that represents 22,000 watts and a power factor of 0.8.Determine the value of a capacitor placed at main voltage panel to correct the circuit to unity power...

What is the secondary current in a single-phase distribution transformer that is attached to a 480v line when the transformer is supplying 120v to a 16kW reactive load with a power factor angle of 40°. So I have kVA = 16kW/cos 40 = 20.89kVA Is = 1000 * 20.89kVA / 120v = 174A. I don't...

When you connect a capacitor across an inductive load, reactive power (Q) flows back and forth between capacitor and inductor, so (ideally) the generator doesn't need to supply Q to the load. My question is, why doesn't the capacitor supply Q to the generator as well? If only a capacitor were...

I'm trying to calculate the power factor of a three phase synchronous generator torque angle = arctan^-1 (impedance) (sin torque angle/ current x voltage) 90 - torque angle - sin = XYZ power factor is cosine XYZ Is this the correct calculation to use?

I need someone to clarify for me how an increase in torque angle in an ac generator increases the power factor. Does the torque from the rotor force the current in phase with the voltage on the stator.

If you have a purely resistive load, which is connected to the generator via elements such as (transformer, transmission line etc), will the load power factor still be unity or 1.0 (In theory)? Or do the previous components such as transmission line etc affect the load power factor? Many Thanks...

By definition,Ia=(S/3V)* I want to know if there is power factor, say cosϕ=0.8 Should Ia=(S/(3V*0.8)) or just Ia =(S/3V)*? Because in the reference book, it sometimes consider the power factor but sometimes don't, I am quite confused with it.

The problem statement Using the nomogram of FIGURE 10, calculate the size of capacitor bank to give a final power factor of 0.95 for a single phase, 230 V, 50 Hz lighting installation which has a load current of 17.5 A and operates at 0.8 pf. The nonogram gives a value k = 0.44...

Homework Statement A load operates at a voltage of Vx = 125V-rms and absorbs P = 55W andQ = 26VAR of power. Use this information to calculate the apparent power (S) and the power factor (pf) for the load. Homework Equations S = sqrt [ P^2 + Q^2] pf = P / S The Attempt at a...

Homework Statement power factor leading or lagging v(t)=3.5cos(600t-120) i(t)=2.3sin(600t+45) Homework Equations pf=cos(Vθ-Iθ) The Attempt at a Solution pf=cos(-75) =.25881905 I get confused, How do we figure out whether it leads or lags.

Homework Statement Hi guys, I am having trouble with my homework, it states to generalise the circumstances required to avoid a poor power factor (assumed to be less then 0.8) of a circuit, this generalisation must then be proved. Any help would be greatly appreciated. Homework Equations...

Homework Statement Hi, I'm an electrical engineering degree student from Perlis University, Malaysia (UniMAP) and I'm currently doing a Final Year Project. The title is Active Power Factor Correction. I'm evaluating a Boost APFC Board from STMicroelectronics model EVL6562A-TM-80W. The problem...

PLEASE HELP ME, GOOD ENGINEER :D Problem Scenario As an electrical engineer in Rawang Power Electrical Consultant Company, your boss assigned your group to design a power factor circuit to improve the low power factor in one terrace house in Taman Maju Jaya, Rawang. The terrace house...

PLEASE HELP ME, GOOD ENGINEER :D Problem Scenario As an electrical engineer in Rawang Power Electrical Consultant Company, your boss assigned your group to design a power factor circuit to improve the low power factor in one terrace house in Taman Maju Jaya, Rawang. The terrace house...

I tried to get a hold of an engineer for the DUKE power company out here in North Carolina to ask for the reason to their transformers only having a .95 power factor. In THEORY it is possible to have a 1 for the PF, and my electricity class has asked me to figure out why Duke Power co...

Homework Statement In a 60 Hz series RL network, the source is supplying 400 W of real power. If R = 15.08 Ω and L = 40 mH, find a. The power factor. (Indicate if it is leading or lagging) b. The apparent power supplied. c. The reactive power supplied. Homework Equations None were...

R = 100Ω, L=0.5H, supply voltage vs(t) = 12sin(377t) in Figure 1a XL = wL =377(0.5) = 188.5Ω vrms = 8.485∠0 Z=213.38∠62.05 Ω I = 8.485∠0/ 213.38∠62.05 = 0.0398∠-62.05 A VR = 3.98∠-62.05 V VL = 7.502∠27.95 V PT = 0.0398[SUP]2[SUP](100) = 0.158W QT = QL = 0.299 VAR ST = 0.338∠62.05 VA Fp =...

Homework Statement See attachment. Homework Equations V(t) = Vmcos(\omegat + \theta) P(t) = VmImcos(\omegat + \phi)cos\omegat PR(t) = \frac{V^{2}(t)}{R} PF = \frac{P}{VeffIeff} S = VeffIeff Pavg = Ieff2(Re(Zeq) The Attempt at a Solution (a) Ieff = 5 A f = 50 Hz or \omega \approx 314 rad/s...

I found total impedance to be 14.23 ohms with an angle of 20.15. Found power factor to be .938 Pretty much stuck at a dead end trying part 2 and 3.

Homework Statement http://i1226.photobucket.com/albums/ee410/jean28x/8b1ad092d9dd25a8f10f1672c0073d97.jpg Vs = 480<0 rms. P1 105 W; pf1 0.7 lagging; P2 5 × 104 W; pf2 0.95 leading. Homework Equations S = sqrt(P^2 + Q^2), = Vrms* Irms(conjugate)The Attempt at a Solution I know how to...

I have a query about the power factor change in a power plant. There are 8 gas engines in parallel. When 1 engine runs with a set p.f of .8 the output at the delivery after transformer (11/132kv, step up Ynd1) is almost same. But when all generators are running with each having .80 p.f the p.f...

Homework Statement Consider this circuit. Calculate the complex power for the circuit, and correct the power factor to unity by connecting a parallel reactance to the load. Homework Equations The Attempt at a Solution My attempt: Can someone check? Thanks a lot!

Homework Statement An RLC circuit has a resistance of 105 ohms, an inductance of 85.0 mH, and a capacitance of 13.2 μF. What is the power factor for this circuit when it is connected to a 125-HZ ac generator? Homework Equations Well I'm not completely sure which equations to use, so here's some...

In AC circuits, it seems that there is no energy used for capacitors and inductors. I was wondering how is the energy used causing it to increase and decrease the power factor?. And also, why does the power provider have to supply power(apparent power) for something that is ultimately not...

Hi Guys- So, I'm new to the Power Quality world but have worked in the VFD world for some years. The term "KVARS or VARS" is new to me. Looking for a simple explanation and how they work in a system. Thanks!

I am new at this energy management stuff: My question is, we have a new Central chiller plant where I work that feeds 5 buildings for there A/C. The Power factor at this building is 99% when the chillers are running (outside temp above 50 degrees) but when the chillers are not running the...

Homework Statement A 50 KW load operates from a 60 Hz 10KV rms line with a power factor of 60% lagging. Determine the capacitance that must be placed in parallel with the load to achieve a 90% lagging power factor.The Attempt at a Solution for 60% p.f:- θ1 = Cos-1(0.6) = 53.13 degrees Q1 =...

In an assignment I was asked to improve the power factor of a certain circuit to 1. The supply is 240V peek-to-peek @ 60Hz. Rs = 58 ohm, Rl = 2 ohm and L = 8 mH. Below are my calculations but I can't seem to get the right answer. Indicating where I am going wrong would be a huge help :)...

Homework Statement I understand power factor is defined as (average power)/(apparent power) or cos(theta v - theta i) where theta v = load voltage and theta i = load current. Also the power factor angle is equal to the load impedance. I don't understand how the 2 definitions of power...

I have a heater coil (purely resistive) of resistance say R. If I hook this resistance to the mains, I get power of V_source_rms ^2 / R. I don't want that much power. So, I use some power electronics switching device, and hence reduce the effective V_load_rms to a lower value. So, my new...

how to find power factor of the load, the three voltmeter readings are V1=220v,V2=122v,V3=136v

What are the disadvantages of having low power factor?

I have been trying to understand how to calculate real power and power factor in an AC circuit when given only circuit voltage and real/true current as measured by a current transformer (CT). What I (think I) know: 1. Real power P = I^2 * R (but I don't know the circuit resistance) 2...

hi, iam wondering about the unity power factor .. for example if we have a motor that will cause the power factor to be lagging by 0.3 what will happen if we add capacitor to make the power factor 1 (unity) now we will not have any reactive power and we reduced the current to the minimum...

Dear all, I have one 22KW motor. I want to know how much Kvar i need to install for it. According to my information, i need to check no load current of motor (it is taking 10 ampere at no load), and than take 90% of no load current (90% of 10 ampere is 9 ampere), so install capacitor that...

Homework Statement Homework Equations If I want to figure out how much money we are losing because of poor power factor and the information I have is Power Factor 60% and total KWH I can take 60% of my total and then subtract that from my total then multiple the subtracted number by my...

Homework Statement See statement below. Homework Equations The Attempt at a Solution I've been reading through the notes for my course and in the section where we are determining the parameters for transformers. For the OCT they give, 240V, 1.066A, 136.6W From this they...

Hi all. In the following circuit, z is an inductive load (I mean inductance + resistance). Here is the table of cosφ measured by power factor meter in different voltages: Why it's increasing? Isn't cosφ independent of the voltage of the autotransformer?

1. A single phase half controlled bridge rectifier operated from a120V 60Hz ac supply. The load current with an average value of I is continuous and negligible ripple content. If the delay angle of thyristors is 60, calculate, i) The harmonic factor of the input current...

Homework Statement A balanced three phase Y-connected source has a line voltage of 208V and feeds two balanced Y-connected loads. The per-phase impedances of the two loads are 20+j70 and 50+j30 ohms respectively. Calculate the power supplied to each load by the source. What is the power factor...

A resistance 'R' ohm and inductance of 'L' henry are connected across 240V, 50Hz supply. Power distributed in the circuit is 300W, and the voltage across R is 100V. In order to improve the power factor to unity, the capacitor to be connected in series should have a value of __. a) 43.7 uF b)...

When I have the Vphase (254 V) S phase (6.2KVA) and I (24A) ? Help !

PF is P / S in general. If the transformer is running at 80.1% of full load, the PF should stay the same right since PF = 0.801P / 0.801S = P / S since if the transformer is running at 80.1% full load, the output S and output P would both be 80.1% right? So basically, no matter what load...

Hi everyone! This is my first post here, and I will start with a question: I used the wattmeter-voltmeter-ammeter method to measure both the original power factor of a compressor motor and its power factor after installing PFC caps. The values, respectively, were 0.78 and 0.91. I am 100%...

Homework Statement An industrial electrical load operates from a 50 Hz 10 kV (rms) line with a power factor of 60% lagging. Determine a range of values of a capacitance that may be placed in parallel with the load to achieve a 90 to 95% lagging power factor. Homework Equations Power factor =...

Homework Statement [PLAIN]http://img705.imageshack.us/img705/4462/40230468.jpg Homework Equations Power Factor = True Power / Apparent Power f = 1 / (2*pi*root(LC)) Z = root(R^2 + (Xl - Xc)^2) = R The Attempt at a Solution a)i) 1? Because it's purely resistive, but this...

Homework Statement 240V,50 Hz electrical appliance is rated at 2KW and has a lagging power factor of0.7. a)Determine the appliance's power factor when it is used on a 60Hz supply? b)Calculate the supply voltage required to maintain the appliance at its rated power when operated off a 60Hz...

Hello everyone, I would like to ask a little help from you guys. I am designing a Permanent Magnet Synchronous Generator (PMSG) for a Wind turbine application which is of direct drive (DD) type. Being a DD type PMSG the frequency of the output is very low and hence I had to employ converter...