Rating Definition and 144 Threads

I have a fuel pump consisting of a solenoid coil. I have tested the fuel pump at 12V supply. The pump actuates at 20% duty cycle(200Hz frequency) and draws a current of 1.7A. When I increase the supply voltage to 24V it actuates at 7% duty cycle(200Hz Frequency), drawing a current of 0.6A. How...

A certain mechanical appliance or device is given a rating that says, a certain operation or a certain movement can be performed some specified thousand times. What does the rating really mean? Was that movement or operation performed until the piece failed? Does it mean some advanced test...

I am trying to determine the likelihood of a driver winning a race based on an associated rating as well as the team he drives for. The probability that Driver A beats Driver B = .8504 The probability that Team A beats Team B = .7576 How do I combine these two probabilities, where the outcome...

Hi, From suppliers of bearings, some of them specify the maximum bearing (surface) pressure or the maximum load rating (static or dynamic). What's the difference between this two? And which is most commonly used during selecting and calculating bearings in a mechanical design? Thanks in advance,

Hello everyone. I need to calculate solar energy output (E) from a solar farm. The calculations are based on values from total module surface area in m² (A), panel efficiency (r), solar irradiance (GB) and losses (L) due to dust, cold temperature and ageing, which is estimated to be 0.75. Since...

Masonry and Concrete Firewalls have existed since ancient civilization. Now with Rovers moving in Mars and LHC probing new particles. Is it not possible to design Firewalls not made of masonry and concrete 8" thick which are so heavy? Soon we will stay in hotels near the International Space...

A player has (wins+0.5draws)/(wins+draws+losses)=(200+0.5*0)/(200+0+0) and another has (1200+0.5*0)/(1200+0+1000). This rating shows correctly that the first player is much stronger than the second. Whereas the Elo, Glicko and Truskill rates (roughly about) the first with 800+200*8-0*8=2400 and...

If we have 'N' advanced computers (where N-> infinity) each with exactly the same rating to begin with and make them play with each other for an infinite number of games, what would the shape of the probability density function of the ratings eventually look like?

I work in a Maldivian Utility Company. Our engineering team is pretty weak so I don't have anybody in the company to ask even though this is the state electric company. A supplier quoted us 2 CT meters . Rating for one is given as 1A(6A) and other as 5A(20A) which I believe is 1A basic current...

Let's say that we have XYZ TV channel, which offers wide variety of programs; from cartoons for children to telenovelas to live sport coverage and news. However, the rating agency for TV programs and films (like ESRB for games) rated all such program on teen (suitable for age 13 and up). The...

Trying to calculate the enthalpy of combustion for gasolines with different octane ratings, 95 and 91 gasoline in particular. The thing is, they are mixtures and not compounds. To calculate the enthalpy of combustion, I am trying to find the molecular formula for each of the gasolines, in order...

Non-isolated boost converter Input Voltage: DC8.5V to 50V Output Voltage: DC10V to 60V Max. Ouput Current: 12A Frequency: 150KHz

A coal fired steam plant takes in feed water at a temperature of 70°C and produces 15 tonnes of steam per hour at a pressure of 60 bar and temperature 400°C. The fuel consumption rate is 1.5 tonnes per hour and the calorific value of the fuel is 40MJkgˉ¹. Determine the power rating of the boiler...

Hello Everyone, I'm here in a country which has a 220v single phase. My wife's $700 Microwave/Convection oven just arrived from the US. The rating of this appliance is: 110v, 1750 watts, 15 amperes. I've talked to suppliers here and was told to buy an AVR with a rating(wattage) 5 times more of...

Please below attached which is best oil in my 4 stroke gen set Honda EU 10i, weather temperature attached in my area. I all so have two oil grades > 4T 10w-30 and Coastal Synthetic Blend 5W-30, please advice which will help the life of the gen set

Does anybody know what the 1/10 meaning is in the current rating description for a fuse holder? 1/10-30A 600V For No. of Fuses For Fuse Current, A Voltage Wire Connection Type For DIN Rail Size, mm Features 1 1/10-30 600V DC/600V AC Screw Terminals 35 Covered Terminals...

Hello, Can someone please tell me what the mean rating temperature in the tables provided in ASHRAE fundamentals, ASHRAE standard 90.1&90.2 for chilled water insulation indicates.

Hello; I import karting tires from Taiwan , while reviewing a sample tire sent for inspection for our order, I noticed a change in spec. of Duro rating . We spec. them at 65-75D ,this sample came in at 60-65D ..here is the factory response= Hi Gus, The tire factory explained that the tire...

Hello How to know the rating of this transformer

I have a elctromechanical contactor (contactor is an electrically operated switch - It is larger version of relay) which has following specification, Inductive full load current - 30A Resistive full load current - 40A Why is rated inductive current less than rated resistive current?

I read online that insulation rating of the conductor depends on the voltage rating and not on the current. Can some one explain me how current doesn't contribute to insulation rating? Am i missing something? Kindly explain me

Homework Statement Hello, the question is number 35 in this picture here: http://uploads.im/uEWAf.jpg It states, ''A suitable fuse rating for the mains supply has current rating - (A)10A (B)15A (C)30A (D)60AHomework Equations V = IR P = IV P = I^2 R P = V^2/R The Attempt at a Solution I...

We know that belt drives are limited in their max possible power rating and most high power/torque applications(trucks) use gear drives. I wanted to know the main factor that limits the power/torque rating of belts. Is it Frictional slip or Belt material? If the frictional slip could be...

Homework Statement I read in my notes that "The physical size of a synchronous generator of a particular rating is larger than one of a lower rating" Why is this so ? The Attempt at a Solution Is it because a larger one would be able to supply more power and therefore the rating would be higher ?

building a DC supply with a load voltage of 3.3V and load current of 3.3mA. all the books and schematics I'm seeing is that they're putting the fuse in the primary of the transformer, why? if i were to fuse the primary as well how do i get the rating of the fuse that i'll need? its said in my...

Hey everyone, this is semi-related to electrical engineering and a quick search didn't appear to turn anything up regarding this question specifically so I figured this is an appropriate place to ask this. I've bought this laser diode rated for 1.9 - 2.2 volts for a project I'm working on. I've...

In some aerospace applications you need high voltages in the range of kilovolts. This is commonly supplied by transformers. However, transformers because of their iron cores are heavy. But in aerospace being lightweight is a key requirement. In the thread "Question about power capacity of...

Hi, as I know the burst C rating usually refers to the max current allowed for 10 seconds. if I need higher current for 1 second, I can do it? The heat is the problem here?

Hello, I was wondering if there is any way of increasing a transistor or thyristor maximum voltage ratting in DC? Thanks. Edit: Just to be more precise, I am referring to the off state. I know you can the on state via a resistor.

Is there anywhere we can rate each (scientific) journals? Publication ethics is for both sides. Not only authors should follow some ethics, but editors should also follow. There are some journal editors not following praction ethics.

Homework Statement A single-phase, 2 kVA, 100/200 V transformer is reconnected as an auto-transformer such that its kVA rating is maximum. What is the new rating in kVA? Homework Equations Rating is KV times the current. The Attempt at a Solution For single winding transformer: O/P voltage...

Hello, I'm a bit confused on the term current rating in an ac generator. Is it the one in that I can get in the formula: kW= V*I*PF*sqrt(3) ? or the one in kW= V*I*sqrt(3)? The problem is the data that I have is V, PF, kVA only. I can compute the kW using those data but I'm abit confused on...

What HP of DC Motor is required to run a 2.5 KW DC Shunt Generator?

Hello guys I was going to ask a question regarding 5 star ratings its a hard one for me but it could be simple for you guys here it is, I've got 1115 ratings ( 5 star max 1 lowest ) * What I know so far is my total rating is 4.80 * 696 of these are 5 star ratings * some of the 1115 have not...

List of challenges: Integral Challenge: https://www.physicsforums.com/threads/micromass-big-integral-challenge.867904/ Counterexample Challenge: https://www.physicsforums.com/threads/micromass-big-counterexample-challenge.869194/ Counterexample Challenge 2...

How much PSI can solder take if used on 1/4" threads to connect a air tank and a valve. I think without the solder it will leak air because the threads aren't perfect and i am using a CO2 tank

Dear Forum Members, I imported an electrical equipment from the US which uses 110v, my country used 220v and as such i need to pirchase a step down transformer. The equipment is a piece of antique and doesn't come with much instructions. I could only get a circuit diagram and i am puzzled by...

what is meaning of this ? 132kV Transformer INCOMER CTs (900-600-300/1-1-1-1-1A) NUMBER OF CORES - 5 is it single CTs package or different CTs ?

I have recently purchased this servo motor ,which has rated stall torque of 33 kg cm at 6V. Statical current :16 mA Stall Current: 3+0.6 AOur technical query is,in order to obtain the maximum torque..what current do we need to be able to supply it Is 16 mc sufficient..or we need 3.5A?

If a motor is such-and-such Hp or kW, is that the Output power, or the Input power?

Hello friends, I am doing my collage project in which main concept is to produce electricity from speed backer and want to use this energy for street light. now my que is my total load will be max 0.7 KW and i have no more idea about generator selection so can you please suggest the generator...

I'm evaluating whether indirectly mounted Tapered Roller Bearings (http://goo.gl/FpOEri) are suitable to withstand a given radial and axial loads in both static and dynamic application. I've managed to find the required dynamic load rating C_90 (or C_10) with the help of the book "Mechanical...

For example A computer with a power rating of 400w is switched on for 5 hours for a period of one week. What is the amount of electrical energy used? I calculated using E=PxT 400w x (5hours x 7daysx 60mins x 60 seconds) =50400000j But the answer is 14kwh Why...

How are power distribution cables parallel-ed to split loads optimally? If the cables were exactly identical this would be easy but how is it achieved in general? e.g. Say there's a 11 kV to 420 V distribution transformer but the primary load is some distance away. Assume the load increases...

Homework Statement "A 5 kVa, 240:120 V transformer.." I am just wondering what the 5kVa refers to Homework EquationsThe Attempt at a Solution is it ##5 kVA = \sqrt{P_{total}^2+Q_{total}^2}## or is it ##5 kVA = I_1V_1 =I_2V_2##

Hello, my motherboard recently has stopped working, so I returned it to warrany, they fixed it, but after a few months the board broke again, but unfortunatly the warranty has ran out, so I'm attempting to fix it myself in the freetime :D So I have found a resistor on the motherboard, that looks...

My background is mechanical engineering so not great with the electrical side. I plan on buying a air-preheater (resistive wire heated) which has a power rating of 30kW, supplied by 3-phase. I need to determine whether my 3-phase supply (415V 32A) has a max current that can cope with this. My...

I came across a question: Four bulbs with different power rating, bulb A (240V, 40W), bulb B (110V, 36W), bulb C (12V, 60W) and bulb D (6V, 0.5W) are connected to relevant power sources. Which bulb is the brightest. At first, i thought the highest power will be the brightest. But the answer is...

Hello, I am new to any type of engineering and just have been working with Arduinos and other microcontroller lately for fun. I am creating a prototype for a project that requires me to use a 9V power supply with 1Amp to power the Arduino(note, the arduino only needs around 300mA to run). I...

Homework Statement [/B] The question "What is the minimum wattage rating the resistor should have?" comes after a previous problem I did to determine the maximum and minimum current when given a resistors tolerance. Here are all the values from that problem, some aren't really important but...