Questions tagged [efficiency]

A measure of the overall effectiveness of a system. For example, in power conversion, it would be the ratio of output power to input power.

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34 views

Simple RC circuit connected to Transformer

I am trying to understand about RC circuits and am having confusion understanding power out of the secondary on an ignition coil with a simple RC circuit as load. The output of the secondary coil is ...
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How would superconducting circuits save a lot of power in a small electric car?

From the bottom of the New Scientist article called , 'The superconductor breakthrough that could mean an energy revolution.': Something like 10 per cent of electrical power is lost in long-distance, ...
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Efficiently drive multiple LEDs in parallel with individual PWM control

I'm looking for a solution for driving multiple (around 30) LEDs in parallel. Requirements: Drive 30 identical LEDs with 2.1V, 20mA each. High efficiency (mobile application with limited power) ...
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Power efficiency with Boost vs Buck-Boost using same regulator

I'm doing a few tests and figuring out what will be the best option for what will eventually be part of a battery powered circuit. I have both a boost and buck-boost converter, both using the XLSEMI ...
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39 views

BLDC motor and drive power loss calculation for dynamic application

what I have done so far: calculated torque and speed of the motor (robot arm swinging mass) used equivalent circuit for DC motor as model for BLDC: U_terminal=L* di/dt +(I_o+ I_load)* R_ph-ph +k_emf *...
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What is the difference between Rectification Efficiency and Transformer Utilization Factor?

As I was studying half-wave rectifiers and why they are less efficient than center-tapped and bridge type full wave rectifiers, I came across these two terms that both try and describe how well the ...
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54 views

Losses in solar electric system?

In a typical, simple solar power collector system (solar panels > battery > electric motor), what losses can be expected for a rated wattage of the panels to the charging of the battery? If a ...
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31 views

Copper loss of a synchronous motor at a particular load

Imagine I'm driving a 50KW synchronous motor of full load current of 10A as a generator using a motor. Assume the driving motor losses to be negligible. Am I right about the following statements? When ...
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92 views

Is energy consumption of the 3kw kettle lower than 2kw kettle? [closed]

On the market there are 2kw 1.7 liter kettles and also 3kw 1.7 liter kettles. I understand that bringing the same quantity of water to the same temperature require same amount of energy, but from the ...
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1answer
66 views

What's the difference between a thousand 0.2W LED's and two-hundred 1W LED's?

1000 x 0.2W = 200W 200 x 1.0W = 200W What's the difference in the light output over a given area, in terms of PAR, PPFD, PPF? I grow plants indoors under LED panels. People in this industry say to use ...
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What does this plot represent for 3 phase induction motor?

I got a 3 phase induction motor with the following plot (please see below). On Y axis: Pm + Pfe represent the mechanical and iron losses, Pm being the mechanical losses, and PFe the iron losses. On X ...
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Why does converter's efficiency degrade with higher V_IN?

Please consider the following efficiency graphs of the exemplary MP2384 buck sync converter: What I am trying to understand is why is the efficiency at light loads worse for the cases in which the ...
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121 views

What is the phenomena behind this DC generator plot?

There is a DC generator to be calibrated with its plot below. On the X-axis there is the ratio between the power of the generator/ nominal power of the generator. On the Y-axis there is the efficiency ...
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Advantages of consequent buck converters

Lets assume we have a 12V source (i.e. an external PSU). We need to go down to 1V8 to supply some load. Leaving the costs behind and using only synchronous buck converters, what are the advantages and ...
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Modeling the discharge efficency of grid connected energy storage systems

Short form A battery has a charge and discharge efficiency of \$95\$%. The initial SoC is \$3 \text{ MWh}\$. It charges for an hour with \$1 \text{ MW}\$, then discharges for an hour with \$1 \text{ ...
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Powering arduino nano efficiently with 18650 batteries

I need to implement a UPS for my arduino nano project (using VIN) in case there's a power outage. I tried a single 18650 (NCR18650B), a battery charge module and a step-up voltage regulator but the ...
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How to determine the efficiency value of the inverter we design?

I designed an inverter with a maximum input voltage of 20 volts. I want to make a specification of the efficiency of the inverter that I made using the formula efficiency = (output power / input power)...
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How could one “inverter control” convector heater be more electrically efficient than another?

I'll have to explain it step by step so that you have no chance to misunderstand what I'm asking about. First, what a convector heater is. It's a plasma TV shaped box usually made of sheet steel. ...
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Why do we use RMS current as the input current for calculating efficiency of half-wave rectifier?

Vi = Vmsin(ωt) Im = Vm⁄R = maximum amplitude of dc current Irms = Im⁄2 Iavg = Im⁄π η = Pdc⁄Pi = efficiency Pi = (Iavg)2R Pdc = (Irms)2R Since the negative portion of the wave is not involved : Why ...
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71 views

Three phase AC power measurement

I am trying to measure the output power for BLDC controller, in order to calculate the efficiency of the controller. I came to know that two watt-meter method is one of the method used to calculate ...
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87 views

Low efficiency buck converter

I've seen the circuit below on YouTube. But it has low efficiency and the p-chnnel MOSFET gets hotter as the output & input voltage difference increases (it goes above 100c with heatsink). I don't ...
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78 views

What is the practical difference between Peltiers of different rated current, e.g., TEC1-12706 vs TEC1-12703?

I'm no expert, but from playing with Peltier modules I understand that, for a constant temperature difference between the two sides, they behave almost as a resistive load, with an almost linear ...
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39 views

DC Motor Efficiency at a given operating point

I'm trying to select a motor for a design application that cares mostly about efficiency. Given a required torque and RPM output from the motor, I feel like it should be possible to calculate the ...
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For superconducting inductors, does the “magnetic current” flowing in the ferrite of an inductor suffer from “magnetic resistance”?

In this answer to "Inductor made out of super conductors", the experiences recounted included "ramping up the inductor" or "charging it up". Absolutely fascinating is ...
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What are the draw back of having multiple smps stages in series?

Application output - 100V 10mA Input - single cell lipo 3.7V 5000mAh overall efficiency > 85% required. I tested Texas instruments power bench. Texas instruments power bench cannot generate ...
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Ignition coil circuit efficiency

I have a circuit which pulses an ignition coil and requires a 6W input. Under load it has an efficiency of around 85% and an output power of approx 5W rms (60kV peak at 1mA). Under very high ...
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How Estimate Capacity for a Battery If the Temperature is Changing Constantly

It is the first time I am trying to estimate a battery capacity to can use some devices autonomously. I found this equation: ...
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Battery Ah specs vs actual Wh when charging and discharging

It is ubiquotously stated that Wh = Ah x V. While this is true (at least regarding the units) I have some doubts about the practical aspects of it. Using an example: Let's take a fully discharged (0%...
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213 views

How to estimate a linear power supply efficiency in LTspice?

I have a little transformer that I would like to turn into a 5V power supply. Before building it I decided to model the device in LTspice: The inductance of the primary and secondary windings were ...
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DC shunt motor electrical

A 5KW, 220V DC Shunt Motor draws 2A at rated voltage when running light. If the armature and field resistances are 1Ω and 165Ω respectively, determine its efficiency when running as a motor drawing an ...
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In a non-magnet, excited-coil generator, what percentage of the generator's total output is used to excite the coil?

I am building a DC permanent-magnet generator with the magnets in the rotor. The stator coils are my unique winding. The overall efficiency of the generator is measured with a digital torque meter ...
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28 views

Boost converter for powering SD card

I want to use a switching boost converter that has 3.3V output in order to power an SD card. Also, the input voltage is a CR2477 battery, with voltage ranging from 2 to 3 volts. I have seen that an SD ...
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35 views

Selecting the right PMDC motor and battery

I'm looking at generating electrical energy from a mechanical input being used to rotate the shaft of a Permanent magnet DC motor. However, i'm a bit stuck with selecting the right motor and battery ...
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53 views

Is microcontroller power consumption directly related to its operation time?

I have to decide on a way to measure the efficiency of an algorithm running on a microcontroller/microprocessor. My thought is that I can use the runtime of the algorithm to complete a certain task ...
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100 views

Dual OP AMP setup circuit supposed to pull 2mA, but where is the other 4mA going?

This circuit uses half of the TI dual OPA2626 (not showing the other half of the OP AMP). This dual OP AMP supposed to use 2mA, but it's pulling around 6.8mA (measured at the Grnd pin and also at the ...
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Varying PMDC motor shaft rpm, how does it affect efficiency?

I am working on a project to harvest electrical power from a rowing machine by connecting a permanent magnet DC motor to the flywheel of the rower. However, my knowledge of electrical motors, and ...
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Does the size of switch-mode adapters affect their efficiency?

I know that a rule of thumb to judge the efficiency of a traditional iron core transformer is to look at its size: the larger it is, the higher the number of windings, the larger the core, the ticker ...
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Why is this device power usage so much power and with such variation?

I just got a wattage meter to try to get a sense of where my electricity usage is going. One of the surprises was my cheap drugstore humidifier, which seems to be drawing 640 watts. I have a huge ...
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Efficiency test for motor drives

Hey I have a BLDC square wave controller. How to check the efficiency of the controller alone (not including the BLDC motor). Any suggestions ? I have checked with DC load test machine, but what I ...
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What is limiting my BLDC Motor power Output?

I am using a BLDC 3 phase hub motor and recently installed a motor controller rated for 3000watt (I originally had a 1200Watt controller installed). The motor is rated for 500w nominal 800w peak but ...
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Why is there such a large difference in efficiency in these two boost converter configurations?

Here is the datasheet I realize that the converter has to "work harder" to boost a voltage from 2.8V-6V to 48V than it does from 8V-38V to 48V, but I'm curious why there's such a significant drop in ...
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125 views

How to active limit the current from a DC source

I have a source with variable power output during the time because it is shared with another devices and this source has not enough power to feed my load (a battery charger for a 1 cell 4.2V lipo) so ...
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605 views

Designing MOSFET bridge rectifiers for high voltages

I've been looking into MOSFET bridge rectifiers, also known as "zero IQ" rectifiers, as a replacement for traditional diode-based bridge rectifiers. Here's a simple example: The benefit, of course, ...
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51 views

How does efficiency of transformer change with respect to primary voltage?

Suppose we have a non-ideal transformer such that secondary load is fixed and we change the voltage applied to the primary side. How does efficiency change with respect to primary voltage? I know ...
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Why do LED headlamp bulbs need active cooling?

I decided to install LED headlamp bulbs in my car in the hope that I can avoid replacing bulbs every year. I was quite surprised to find that I can't fit replacement bulbs in my car due to the bulbs ...
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Computer power supplies usually have higher efficiency on 230V than on 115V. Why?

As seen here in the example, this particular power supply (and most others too) has higher efficiency when running on 230V. Given that computer power supplies are usually required to output a ...
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Efficiency of induced power

This is a very basic question which I can’t quite wrap my head around. Say you have a wire/coil in a magnetic field in such a way that if you apply a current in the wire it will move. So you charge up ...
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432 views

Boost converter efficiency

I simulated a boost converter on LTspice and have measured the steady-state output power to be 80.49 W and the average power drawn out of the input source during steady-state operation of the ...
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113 views

Are permanent-magnet motors equally (in)efficient as motors vs. as generators?

Given a permanent-magnet motor with an efficiency of 80% that converts 100W electrical input power into 80W mechanical output power, would the motor have the same efficiency if used as a generator? ...
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Coordination of mechanical and electrical power in electric drives

I want to ask a question to respected specialists in electric drives. It is known that the mechanical power of an electric motor is determined by a simple formula: \${P_{mech}}= M {\omega}\$; ...

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