Sizing Definition and 136 Threads

Hello, this is my first post and I've been out of school for a few years and now working a job in my field at a distribution utility, but I'm just really rusty or green on a lot of things now that I'm being challenged. Seems like the simplest questions elude me! Anywho, I've been tasked with...

Good day, I have been working on load testing for generator sizing of various premises and I used a power and energy logger to do the load testing. The results came out good, now that I got max apparent power in kVA and the max true power in kW. My question is how should I calculate the...

I am looking for the rule of thumb when selecting a wire gage for ground wires on electrical circuits. Currently we use 18 GA for all of circuitry regardless of the amperage of the circuit-from less than 1A to over 30A we use 18 GA. We have never had an issue but I am wondering why 18 GA was...

Two problem to solve. 1) I have 4 propellers built with different airfoils. I have the graphs of coefficient of thrust and efficiency in function of advance ratio. There is a mathematical method to select which one is the best or the only way is just look at graphs 2)I know the maximum thrust...

Homework Statement Suggest one way of sizing the transistors of the logic circuit such that its worst case tpHL equals the tpHL of an inverter with a sizing of (W/L)min. Homework Equations I think the only equation is the (W/L) itself. The Attempt at a Solution I have actually done the front...

Hello, I am trying to design a double jacketed tank for brewing beer. Heating rate rewuired 0.5-1 C/min. Inside capacity of 300-400 liter liquid at ~1.05 d + grain, tank capacity of 600 liter. I can not find a proper calculation for a minimum jacket surface area required for this aplication. I...

Hi Guys, I am aware how to calculate flow rate Q (c x dt), but when sizing a direct gas fired water heater there is no dt but of course need allow for temp rise, but what parts of information can be known and unknown and how would i even start to put a formula together? Ultimately i would like...

I need to make a steel beam ( or aluminum) of square tube ( box beam) 10 feet long with a balance point 2 feet from one end. The short end will have 60 lbs on it and the long end will have 30 lbs. how thick of a wall will the square tube need to be to hold the static load?

Hi all. Please pardon the amateurish question! My hobby is constructing camera traps which I use to photograph wildlife, using small "point-and-shoot" compact cameras. Currently I am working on a project that involves removing the flash unit from the camera proper and installing it...

I recently shifted to South Korea to pursue higher studies and stay with my sister and niece . My niece is working on a high school project on air pollution and indoor air quality studies . Starting with a write up on air pollution and then indoor air quality and effects on health and the...

I am trying to complete a project and have to properly size some steel tubing. The project is a belay bar for a slackline we have in the yard. I have 2 poles that are set in the ground 21' apart and a slackline runs between them. We want to run a steel tube beam, permanently attached to the...

I'm working on a senior design project. Currently I'm having some issues with sizing a motor for a large robot; everywhere I look I get different advice. I have a motor that I think will work but would appreciate some input. The specs are for our robot are as follows: mass = 350 lb = 158.8 kg...

Homework Statement A 400-liter CSTR and a 100-liter PFR are available to process 1.0 liter of feed per second. The feed contains 41% A, 41% B, and 18% inerts. The irreversible gas-phase reaction A + B → C is to be carried out at 10 atm and 227 °C. The rate of reaction in mol/liter min is...

I am troubleshooting a 1967 GE synchronous motor used to run a reciprocating compressor. It is a 1000 HP machine. I am trying to figure out the size and purpose of the capacitor connected to the DC field. Is it there to absorb voltage fluctuations? The capacitor has burnt up and can't be...

I am trying to size a needle valve to make sure that it can allow the required flow rate at the fully open position (0.025 m^3/s). For a given Cv you should be able to calculate the maximum flow rate through the needle valve provided that you know the temperature of the gas and the pressure drop...

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've just got into my electrical engineering course and I need some help with a question of mine here. During a site visit, we were shown a main LT panel which has switchgears, ammeters and different kinds of relays and the distribution network from that panel. In the main LT panel...

I have a problem at work and unfortunately it has been too long since I have been in a class room for me to reason this one out, never did like fulid mechanics much :). We have filter that is pressurized to approximately 55 psi. Once ever 12min or so this filter purges a volume of ~2L that...

Hello, Is it true that when using transformers and three-phase drives/VFDs for induction motors, the transformer's power needs to be much higher (e.g. +40%) than the drive's in order to avoid increased harmonics (or even other problems)? If you know any official standard, paper or...

Good afternoon, I am trying to size a reduction orifice for a desired pressure drop. I do not need the drop to be specific, since this is just for valve protection and not for metering. D1 (Pipe) = 2.5" P1 = 125 PSI P2 Required = 75-85 PSI Q = 1020 gal/hr Fluid = Water, 90 Deg F...

In general, by what considerations guide the decision to size a capactior to smooth voltage signals? For example, if I were to use a 3.3V regulator in a circuit design, what size cap should be set in place to ensure a smooth regulated voltage? My attempt at answering my own question would bet...

I found this sizing chart for ventilation ducts. Notice the gray area for what I suppose is the accepted pressure loss area. What I wonder is why it changes as the sizes pass Ø800. From here on the upper pressure loss limit goes down to 0,7 Pa/m. Is this because of velocity issues or something else?

Hello all, I an trying to size a motor to drive two mechanisms but am having some real trouble getting my head around the required torque. First let me explain what we have. Basically there are two mechanisms where I have plotted the speed and torque requirements on this graph as you...

Hello everyone, Thanks in advance for any wisdom you can offer regarding this matter, I just joined physicsforums.com and am now wondering why I haven't been a member all along... My crudentials: I'm an electrician that went part way through college for electrical engineering, however Its...

This might be a silly question for some but I was wondering how do I size a DC motor to move a weight and counter weight? Suggestions for a better design are also welcome. I want to build an enclosure with an automatic door (simple limit switches and an arduino to flip the motor on and off)...

Dear EE'S! I need help -- sizing electromagnets Is it possibile to built different electromagnet's sizes, that can produce the same magnetic field and forces(e.g attraction/repulsion)? If so how can I do that? By following this law: B = unl By controlling the number of turns or the amount of...

Hey all I have what I assume to be a fairly vague question. I'm taking a programming class right now for MATLAB and the current project we are working on is a simple histogram display from reading an excel data file. The coding is extremely easy however, having never taken a statistics course...

480 V primary 120 V secondary. 9 temperature controllers and 2 power supplies coming off the 120VAC total Amps are ~10A This is 3-phase. How do I find the right size transformer?

What things do I need to consider when selecting a proper sized power supply? Basically this is control power, ouputs are pushbutton lights, alarm horn, and solenoid valves. Do I look at the peak inrush current? Average holding current?

Need help with motor sizing/torque calculation - Building a Ski Rope Tow. I am building a homemade ropetow in my backyard. I have done a lot of research and unfortunately I have been away from physics for about 15 years, so I am having trouble calculating my motor size and transmission...

Hello. I need to estimate height and diameter of a cooling tower. My water requirements are 50000 m3/h, for a cooling duty of about 730 000 000 kcal/h. For this capacity, I thought that an hyperbolic tower, natural draft, would be the best choice. Am I right? Water temperatures in-out would...

Does anyone know where i can get the calculations for sizing an inverted screw pump. Inverted being that there is no screw but the fins art attached to the inside of a pipe and the pipe is rotating. I am moving any where from 150 to 400 lbs of dry powder per minute, depending on the amount of...

I am attempting to size a wind turbine generator where the torque available is 8,000 Nm's. Can anyone save me doing the calculations? Regards AV8TUR.

I am new here and don't know if this is appropriate so let me know. I am not an engineer and no formal training other than a few Physics classes in college many years ago. I do however have a high mechanical aptitude and have always done some personalization of machines. Eg. I put a lawn mower...

I'm in need of an extension spring with some specific requirments: Material: Stainless Steel Diameter 0.75inch Rest Length: 5 1/2inch inside the hooks At 7 inches a forcle of 10lbs At 10 inches (full extension) a force of no more than 20lbs (As low as possible) Any idea on how to size...

Homework Statement A glass manufacturer operates 11 months of the year and produces 97,000 tons of glass per year that needs to be cooled to ambient temperatures. The melting point of glass is 1673K and ambient temperature is assumed to be 293K. The specific heat capacity of glass is 0.837...

Hiya I was hoping that somebody would be able to help me. I need to size a shaft coming from a turbocharger spinning at 150,000rpm the shaft needs to transmit 9Nm and 200mm in length, the shear stress of the material is 457MPa. I need to size the diameter of the shaft and know that it...

Hi there - this is my first post and I hope one of many to come! My query is a relatively simple one; I'm working with an engineering cleaning application where fluid will be fed into a cylindrical block and spun out into a surrounding container. The block is 3.5m long and ∅0.140m...

Hi all, I have a question. I have been asked to estimate the size (thickness/gauge) and specific material of two L-Brackets that will be used to mount a condensing unit on the side of a building. As I am at work and don't have any of my school/ME books at my disposal I am wondering if...

Hi! I'm looking for information on how one would size a wide-flange beam knowing the live/dead loads and the span required i can't seem to find any calculations for this sort of thing! beam is not composite with floor

Well i am currently working as a project engineer for utilities at my factory .This is my first installation of chilled water system.So would be requiring some help in sizing the Chilled water supply and return tanks.I am attaching the picture along so that the system is easily understandable.

Hello, I need to size a motor for the following conditions,and I have managed to completely confuse myself: Motor will turn a hollow cylinder Cylinder mass = 10000kg radius = 0.759m acceleration = 0.25m/sec/sec Cylinder speed = 19 rpm I've been calulating the torque by: T = (I *...

Sizing a pressurizer for a PWR plant!? Homework Statement So I can't find anything online to help me with this because there isn't very many resources for this. If anyone knows of a good resource that would be great or some pointers on how to get started on this. I am working a problem...

So I can't find anything online to help me with this because there isn't very many resources for this. If anyone knows of a good resource that would be great or some pointers on how to get started on this. I am working a problem trying to find the volume of a pressurizer... here is the...

For about a year and a half now, I've been writing down stuff I've learned into a bunch of LateX files, to make it easy to refresh my memory when I've forgotten something, and perhaps also to be able to show some of it to other people at some point. In order to make it look nice, I chose to use...

I plan on using a very large solenoid for a magnetic field experiment. I have estimated what I believe to be the inductance and resistance of the solenoid and, with the desired field to be produced, almost 20 amps will be required. After running a simple simulation, I am not sure how to...

Homework Statement I am struggled by a problem encountered in studying SMPS, on reading the book 'Switching Power Supply A-Z', for a passage talking about the effect of increase in load current of a DC-DC converter on the inductor size, from the ripple factor formula, r=(delta I)/I_L...

Hi to everyone, I have a problem with sizing pipe threaded elements. I am looking for guide rules that with a simple external meassurement I'll be able to determine the element size such as safety valves,threaded pipes,pressure gages,caps etc. To clarify my question, hereby an example, when...

Hey guys, I'm looking for some software capable of allowing the user to input a specific mission profile and ultimately calculating empty weight and fuel weights providing input such as your L/D, cruise altitude, AR, Swet, Sref, ect. I'd even be interested in more advanced programs with the...

Can someone please guide me (with an example if possible) on Cable Sizing Calculations. I want to learn the step by step procedure alongwith calculations that are performed during the preparation of Cable Sizing Documents. Thanks in advance!