Electric Machines - Science topic

Hello everyone, I was wondering about the convection phenomenon in the airgap of a permanent magnet machine. I found in the literature that we need to look for the Taylor number and then Nusselt number based on the flow type (speed) to find the thermal resistance in the airgap. But what about the boundary condition temperatures on the inner stator surface and outer rotor surface? Are they necessary to determine the temperature in the air gap using the LPTM model?

I am interested for designing machines with permanent magnets.

Where and what elements generally use reactive power? Is reactive power generated along with true power in generating stations? If so how are they differentiated? How come capacitors used as compensators that generates reactive power using active power?

Flash over occured in  HT Motor Feeder Driving a Centrifugal Pump which having leakage in its Non Return Valve. Thats Why over current was drawn by motor. The Motor has been fed through 6.6 KV Vaccum Contactor Feeder. In case of over current the fuse has to blow instead the power fuses were broken into pieces because on flash over. How to prevent this situation.

I have simulated the 0.37KW capacitor start induction motor in ansys maxwell RM Xprt. Its efficiency is 45% (percent), results attached. These are no load results. I have few questions

How to perform the on- load analysis of motor using RM Xprt or 2D analysis?

How to optimize the winding design, wire size and no of turns etc.?

How to select the starting capacitor for this motor?

How to select the rotor shape, its dimensions and torque optimization?

How to increase the overall efficiency to fulfil the IE1 and IE2 standard?

Simulation results shows that stator losses are 129watt, thats hufe losses in 373 watt motor, How can I reduce it ?

How to select the switching time of auxilery winding ?

Any paper, books, tutorials or presentation or videos that can help me in this regards. Please share

Your kind support and recommendation will be highly appreciated.

Thank you

I am trying to check The dynamic behavior of the induction motor speed with 50% raise of (Lr) relative to the identied model parameters. I am using  Asynchronous Machine Simulink block. I want to change the rotor inductance without change the stator inductance in Asynchronous Machine Simulink block. 

It is clear that we have forward and backward rotor currents. My question is: Which component has higher amplitude assuming that the rotor is rotating; the forward component (having frequency of sf) or the backward one (having frequency of (2-s)f). Analysis of the equivalent circuit tells me that the backward component should be higher. This is in correspondence with the fact that as the rotor mmf demagnetizes the stator mmf, then the total backward mmf will be lower than the forward one. In contrast to my justification, there is an oscillogram of the actual rotor current showing a high amplitude forward component carrying a backward low amplitude component superimposed on it. For instance, you can look at the generalized theory of electrical machines book by Professor Bimbhara. What is the reason?

To my knowledge, electric machines (motors and generators), apart from their electronics, are made of at least two or more of these materials:

This list is non-exhaustive, I may have some not coming to my mind right now and I do not know every process and possibilities offered by academics and industrials and this is why I am asking this question. How can a low ecological footprint, joining also the field of low-technology (lowtech), electric machine be made?

I come with a BLDC background (electric motors with stator (steel sheets, copper coils wound close or onto it), rotor (ferrite and rare-earth magnets), steel shaft, roller bearings, and aluminum frame), but I am open to other types such as SRM, wound-rotors, etc. For each of the necessary elements (rotor, stator, bearings), I am wondering what would be the best performance yet lowest ecological footprint material available.

As a starter, I was thinking about a SRM or a BLDC with as little iron as possible in the rotor, with as little too in the stator, with carbon coils (is this even possible to manufacture?), all running on plain bearings/bushings made of a low impact plastic.

All ideas are welcome, my aim is not to fill a patent, but to open a discussion about possibilities to reduce human impact of a polluting industry.

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About the impact:

Found on interesting paper published by MIT and NEMA. Pages 34-35 , the usage of a 25HP motor accounts for 99.8% of the impact (CO2 produced).

Also report from ABB:

Thus, is the question I am asking really relevant? In a vast majority of usage, highest effiency motors would be the way to really decrease the impact on environment, and low footprint materials/manufacturing with lower performance/effiency could only be useful for power generation (but then comes the problem of infrastructure required)?

In application for spring charging mechanism with universal motor how motor torque is specified for variable mechanical torque requirement?

if a generator loses its residual magnetism how it is started

What is the difference between normal linear motor simulation and a tubular linear motor simulation in 2-D? Although a normal linear motor and a tubular linear motor are obviously different but in 2-D simulation of both motors, what will we have to do different from normal linear motor simulation? 

Does anyone have a link to Ansys Maxwell tubular linear machine simulation tutorial? I tried i could not find any.

To verify if the system satisfies the observability property. Several techniques and tools have been developed to study whether a nonlinear system is observable or not. Generally, the observability property study of a nonlinear system are depended values when the expression of determinant (D) are canceled for limited points but not for all operation modes such as in the case of complex expression of determinant.

How to set the parameters of Doubly Fed Induction Machine for a 32 MW Machine for Variable Speed Pumped Storage Systems in PSIM

Is any process of magnet insertion into a bldc motor... 

I want to know definition of electromagnetic conjugate for electric machine (preferably motor)

I have a working model of a healthy 3-phase induction machine based on Krause's model, but need help to model stator and rotor faults to analyse the current spectrum. Any help would be very much appreciated. Thank you. 

i looking for the answer

The sample machine has been fabricated with 110N-m ....

Prime mover and PM machines

why distribution transformers are rated exactly at 25 KVA and 63 KVA and 100 KVA?

Hello everybody. I need experimental data of an induction machine operating under different failure conditions such as inter turn short circuit, broken rotor bars, bearing faults and eccentricities. So, anybody have an idea of the place where I can find these data. Thank you all for your interest.

I am not particularly sure about the switching speed of these three components. (Please note: that this question is with regard to an ongoing project on the design of Universal Solenoid drives, the details of which are in my profile. Thank you.)

If there are 5 rollers which are required to be run by the help of a chain connected to an induction motor. Then how can we calculate the exact KW capacity of motor? How to decide that which rating is suitable for this task?

I need to  parameters of Stator and rotor (=such as resistance and inductance of rotor and stator) for a Induction motor 2.7MW, 3kV.

How can we get the load cost vector? The elements of this vector represent the independent load values or costs of the corresponding bus. The unit of the cost is $/kW or $/MW

Optimizing an electric water pump from a performance point of view, particularly by centering the maximum performance of the electric motor at the hydraulic working point

Thank you very much.

Current transformer size is 1600KVA, Most of the time distribution transformer 11/433 V is loaded about 10%. Adequate data is not available to determine no load and on load losses. Will the underloading lead to significant losses? What should be the ideal rating of the transformer?

Motor specification:

Type: BLDC

Power: 500W

Voltage: 48V

No of motors: 2

I just start to study about synchronous reluctance motor and want to simulate it and control its speed in Matlb .

What is the best synchronous reluctance motor state equation which can use in drive simulations?

(Reluctance Synchronous machine)

I am trying to use 9 V DC relay board to power 24 V DC pmeumatic valves (normally open, from FESTO) and I do not see any change in pressure while the valves are supposedly ON-OFF. I tested the system with a 20ml syringe to check the pressure. I do not have knowledge in electric, thus I wonder if it is impossible to use such a system, if, the power from my relay board is not enough to actuate the valves? Or, if the way I check it is not really manually sensible? (the valves go up to 0-6 bar) 

i am designing the bldc motor , so what parameters consider while designing it.

in my research i will use this technique to distinguish between saturation harmonic and mixed eccentricity faults for squirrel cage induction motor, so can you explain me in detail for this technique.

Thanks

A.Chaouch

Hello, I am trying to estimate the stator resistance of an induction motor (online) by using back emf  of stator quantities  and the rotor quantities respectively and a PI compensator. The problem that i am facing is that  as the operating conditions ( as increase / decrease  in speed  or  increase / decrease in load torque ) the value of resistance varies from (0 to 15 ohms)? Can i get any suggestions how to estimate the stator resistance?

Thanks in advance

dear sirs,

I am just starting working on 2 HP induction motor.I will use simulink, but I have missing data like inertia . can anyone help me in this point.

In symmetrical three phase fault analysis, we represent the equivalent circuits with sub-transient, transient and steady state d-axis reactance. Why don't we use q-axis reactance to model the generators under fault in these cases?

I am trying to model a lookup table using the table attached. How should i go about it?

We transform source current (Is) of Single Phase Active Front End Rectifier into Id and Iq. What should be the nature of Id and Iq? Is it possible for Id and Iq to be negative?

I have following data about my symmetrical mechanical load. I want to choose a suitable electrical machine to rotate this load at 6000rpm. How can I determine the minimum and maximum logical acceleration in conventional motors (There is no data in the motors' datasheets in this area)? How can I find the starting torque for each machine by means of their datasheets and nameplates?

Moment of inertia: 0.02kg*m^2

Operating speed: 2000-6000rpm

We are building an electrospinning system and we have tested the fiber produced and we found that we have reached nano-scale. Now, we want to optimize this system by installing a drum with motor to obtain best distribution of the fiber and we can not connect the negative charge to the rotating drum.  

Hi,

I am working on AC magnetic susceptometer to detect response from magnetic nanoparticle solution. I am using counter wound and series connected coil setup as the pickup coil to get the voltage response from the nanoparticle in a response to applied AC magnetic field by another coil.

Though I can change the vertical position of pickup coil assembly inside the excitation coil I am getting some feed through from the pickup coil even after tuning. I am calling it a tuning point because I can get rid of inductive background by changing vertical position of the pickup coil setup. Can any one suggest me how can I compensate the voltage feedthrough in the pickup coil?   

When I connect PMSG with VFT in MATLAB, it is showing an error and please tell me what device is used to interconnect both.

In electrical engineering, electric machine is a general term for electric motors, electric generators and other electromagnetic machines. They are electromechanical energy converters: an electric motor converts electricity to mechanical power while an electric generator converts mechanical power to electricity. The moving parts in a machine can be rotating (rotating machines) or linear (linear machines). Besides motors and generators, a third category often included is transformers, which although they do not have any moving parts are also energy converters, changing the voltage level of an alternating current [Wikipedia, 1].

[1] Flanagan. Handbook of Transformer Design and Applications, Chap. 1 p1.

I am involved in a research project in which I have to specify a method to detect on-line turn-to-turn fault due to insulation failure in the stator winding of medium voltage induction motor. Anybody is having any idea, that are welcome. 

I am making a 19 x 19 mm magnet which will be use to attach on an accelerometer for vibration analysis on a three phase induction motor. Instead of by using strong glue, I was thinking of using screw as mean of joining between the permanent magnet and the sensor.

In the phasor diagram of practical transformer under no load, does I_w account for hysteresis only or for both eddy as well hysteresis loss ??

I am trying to simulate the dynamic behavior of the Doubly-Fed induction generator in Matlab. For that, I have developed my DFIG model in Matlab as a script. The solution of the system of the ODE converge, but I think the result is inaccurate. Could anyone help to find the problem in my model. Any suggestion of how to improve the model is highly appreciated. Thank you very much.

I need to charge a rotating mandrel collector up to at least +/- 10 kV. I am unsure of how to interface a high voltage power supply with the actual mandrel. Thanks for any help.

Rated voltage: DC12V

Rated power: 2 ~ 3W

Reduction ratio: 8300 / 200RPM

Motor no-load speed: 8300RPM

load speed:200RPM

Rated torque: 0.4G.CM

Motor size: 34x25mm/1.34 x 0.98"(L x Dia)

Total Size: 77x31x36mm/3.03 x 1.22 x 1.42"(L x W x T)

Weight:147g

Hi People. In need help from you. I want to measure the maximum load capacity of a cranck shaft forging press. I dont know which is the way to ensure that the measure value is real. 

Maybe some of you can give me a procedure or paper or some useful recommendations.

Thank you Sirs!

I have been having problems with a DC Motor. Unlike our other motors it is a Compound motor vs. a Shunt wound only. We are not connecting the Series leads at all in the motor connection box and connecting A1 to A1 and A2 to A2. F1 to F1 F2 to F3 and F4 to F4. The motor runs erratic and at higher amperage when loaded and eventually shuts down on overcurrent. We are using an ABB DC drive. We do not have this problem with our straight shunt wound motors. Tuning is conducted prior to operation and is successful.

i want to develop SCADA in laboratory can you please suggest me the best way to develop. It is for recording the data such as voltage, current, power factor etc from the electrical machines. which software would be easier to implement the system. 

Thanks in Advance

How I can determine the parameters of a DC motor experimentally using speed vs input voltage?

I am working on electrical machines which is dipped in fluid having density of 0.9 gm/cc, viscosity of 10 sq.mm/s, pH value of 5.5 and acid value of 0.03 mg KOH /g.I am searching for an insulating material which can automatically travel through this liquid media and stick at the hottest spot (having temperature 150 degree Celsius) on the machine.Can u suggest any material?

In other words, if rare earth PMs are usually used or conventional types?

Am trying to refine my Finite Element Analysis to take into account of the small gaps that must exist between the magnets and the rotor slots that host them, in order to be phisically able to insert the PMs in the slot.

These small gaps will provide for some marginal reduction of the magneto-motive-force produced by the magnets.

I want to capture this effect without being forced to have a very fine mesh in such gaps, so I'd like to model the PMs as completely filling the slot while properly modifying their properties (coercitivity and permeability) in MagNet, obviously achieving the same result of flux distribution in the machine as achieved with the real, "gapped" structure yet in a more computationally efficient way.

Has anyone developed a method to do this?

Thanks a lot,

Francesco

The no load flux linkage depends on field magnets in a permanent magnet motor. Does this no load flux linkage also depends on winding factor somehow?

As we all know, manufacturing machines whilst in operation produces unwanted noise and vibrations. These are the forms of energy that is usually lost. Is there any possible way as to using a piezoelectrical device to harness this energy? If this is possible, then the same energy can be used to supply partial electricity to the machine thus saving some energy and finally saving money.

I work on DFIG. Do anyone have the model of induction generator with considering the saturated effect of inductance???????

Normally we use Voltage Source Inverter ( Asymmetric bridge converter ) in controlling Switched Reluctance Motor, wouldn't it be better to supply current from Current Source Inverter directly to SRM. We know square shape unipolar current is given to SRM, so why use VSI, why not CSI?

Due to parallel winding in electrical machines, current gets induced into it and it circulate. How does it reduce vibration? 

Hello everyone, I want to distinguish BLDC and B through the external shape and the specific applications they use BLDC .

In practical synchronous machine, is the minimum armature appear at normal rated current i.e 1 p.u. excitation at no-load? 

What are the factors to decide the switching frequency in DTC?

What is the fifth-order aggregated single phase induction motor model  ?