# Search results

1. ### Cons of Stopping shaft connected to gearbox

First of all, a gearbox only changes the speed. So to determine if you need one you have to look at the shaft rotation speed in relation to the generator nominal speed. Problem is what are you going to do with the electricity produced. It is intermittent so you may want to store it in a...

You have two equations and two unknowns; L , A. Should be basic algebra. R = rho * L / A L = 500 * "circumference of one turn" <---- given by geometry of your coil/core
3. ### ANSYS Maxwell Impedance Matrix

If you are unsure of how to interpret the results for three conductors. Remove one current/voltage source and simulate the system as a two circuit system, e.g. current in circuit 1 and 2. This will give you the case as in the documentation, with L11, L12, R11,R12, … ,R21. Then apply current to...
4. ### DOL Motor Starter can support 160KW, 1000KVA Pump?

It mainly depends on the grid it is connected to. The problem faced with starting is the voltage drop in the cables/grid becomes to large due to the large starting current. Thus a reduced terminal voltage will reduce the output torque of the motor, and it may not be enough to overcome the load...
5. ### Cons of Stopping shaft connected to gearbox

I dont understand what you mean, so you have to elaborate some more. What is the prime mover of the shaft? What is it connected to? Why do you need a gear box? Do you need to break the shaft every 1 minute? Do you want to generate electricity from the rotating/kinetic energy stored in the shaft?
6. ### Very silly question regarding DC motor

I would try it out. Set the voltage limit "low" at first, measure the current and maybe the temperature of the motor (simple PT100 element or similar, its also very fun an interesting to just experience it). Measure the current with a ammeter or oscilloscope (if available. Current rise/peak may...
7. ### Very silly question regarding DC motor

From my experience, it is neither the voltage or current that breaks the machine, it is long exposure to high temperatures. That is, the insulation degrades due to the high temperatures. Current are of course the central factor in the temperature distribution in the machine, but thanks to the...
8. ### Servo Mechanism to initiate movement of an electric motor trolley

Choice of motor also depends on your power source (i.e. battery, fuel cell, generator), load torque (you have said 400 Nm, based on what?), power ( what speed do you want?, air drag coefficient etc.) and speed/gear ratio. A DC motor might be the simplest motor to control, so it would be a good...
9. ### Servo Mechanism to initiate movement of an electric motor trolley

Are you looking for advice on selecting a motor (drive system), or the control part of the system, i.e. the sensing of motion/force in a direction?
10. ### Faraday's law

Look up "Lenz law"; "An induced electromotive force (emf) always gives rise to a current whose magnetic field opposes the original change in magnetic flux."
11. ### Motor circuit excessive heat

You mentioned that you changed the gear ratio. This would change the load torque on the motor, from low to high. And since it does not run/spin the load torque is higher than the torque produced by the motor. http://en.wikipedia.org/wiki/Gear_ratio Torque is proportional to current and it...
12. ### Induction coils and contact materials

2500 degrees Celcius are some serious temperature! What is the application if I may ask? Shielding can be done in two ways. Either by conducting the magnetic flux trough a high permeability conductor ( that is, the flux is confined to inside of the material) or using a high electrical...
13. ### Generator selection help

Well, torque is not drawn from anything. But the generator creates a "counter torque" acting in the opposite direction than the torque created by your motor. A equal torque and opposing torque will prevent a acceleration (Newtons laws, right?). As efficient as possible is one of the biggest...
14. ### Can we use earth as neutral?

The "quality" of your voltage depends on how the transformer is grounded. In a floating neutral point or delta connected secondary a phase-ground connection would not give the same function as a phase-phase connection. But it would still be a potential difference between one phase and ground...
15. ### Generator selection help

Just to clarify. Are you designing a internal combustion engine, the one you refers to as the motor, or are you designing a electrical motor? Anyway, what "type of electricity" do you want? AC or DC? 50 or 60 Hz? What "grid/network" are you going to supply? According to conservation of energy...
16. ### Maxwell 3d linear motor

I guess he means Ansys/Ansoft Maxwell 3D, a FEM software. As for help, not every problem has its own tutorial. ( This is called engineering ) But analyzing a linear machine is similar to a rotating machine. Use the knowledge about FEM modeling from the rotating machine, read up on how a linear...
17. ### Operating principle of a Six Phase induction motor

Try using the same approach as with the 3-phase machine. The approach should still be valid. Doing the math may be simpler than trying to think about how it works. Also note that in a 6 phase system each phase is separated by, not 120 degrees, but ? Draw a diagram with the axis of each phase...
18. ### Operating principle of a Six Phase induction motor

Are you familiar with how the 3-phase motor creates a rotating field? Where a pulsating wave is composed into a forward and backwards traveling wave? And how the sum of these waves creates a forward rotating wave? Draw a vector diagram for the coil layout, take one instance of time and draw...
19. ### Pelton turbine model when hydroelectric station works on grid

I didn´t, just a guess based on own experiences. Ok, it makes sense. But the extent depends on how large the grid is and what load sinks there are. Have you done some research and found a proper value? Ok, I have misunderstood your system. I was talking about the whole system. I think you...
20. ### Effects on a cable at sea level compared to 35,000 feet

To the OP, have you done some research? E.g: http://ieeexplore.ieee.org/xpl/articleDetails.jsp?tp=&arnumber=6440678&queryText%3Dcables+airplane
21. ### Pelton turbine model when hydroelectric station works on grid

Sorry for the late answer, but during the vacation I forgot this thread. I re-read your first post, and you mentioned a "dump load". Can you clarify what you mean by that? I have yet to encounter such a "object" in a normal power system. But it may be possible to incorporate such a object...
22. ### Electromagnet heat source and efficiency

In a electromagnet one can basically divide the power losses into two categories, winding losses and core losses. Winding losses are caused by the current flowing in the coil/winding of the electromagnet. These losses are equal to : P=I^2 R, where I is the current, and R is the resistance of...
23. ### Hydroelectric powerstation with Asynchronous or synchronous generator

The below is related to a squirrel-cage IM in island mode: If you draw the torque-speed curve for motor and generator operation, you will notice how the slip changes according to loading (active power). This gives a direct correlation between the electrical frequency and the rotor speed. As...
24. ### Pelton turbine model when hydroelectric station works on grid

I will try to share some of my experiences when it comes to matlab/simulink, as I have scratched my head to many times trying to get it to work, and I hope you don't have to. First you need to have a opinion and goal on what your model is to describe. What is the output variables you are...
25. ### Worldwide Solar Grid Hypothetical

Solar power includes several other solutions than photovoltaic cells. Some convert solar power into thermal energy, allowing electricity generation after the sun has gone down, reducing the need for a interconnected grid as you propose. Read up on the wiki...
26. ### Symmetrical Components

Have you tried your self? check out wikipedia Or the famous article by Fortescue As a push in the right direction, how many balanced systems (sequences) do you need?
27. ### Why an electric motor is used in hybrid cars

OmCheeto: I would love to see more of your 'inventions', you haven't thought about opening your own thread posting pictures and descriptions of your projects? 'Industry secrets' can be withheld from the public, but general experiences and conclusions would be interesting to hear. I keep getting...
28. ### PMGs on Alternators

Not quite sure what type of excitation you are talking about. But by using permanent magnets directly or indirectly to supply the rotor field winding, the excitation current which again controls reactive and to some degree active power are independent of the terminal voltage. This is an...
29. ### Maxwell 3D (ANSOFT)

It again depends on what effects you want to model, but most times its not necessary to draw each turn.(most times are when eddy currents like proximity effect, skin effect etc. are neglected in the coil/winding) So I would agree with you regarding defining the conductor as stranded, and use a...
30. ### Maxwell 3D (ANSOFT)

If I state that: A solid circular or rectangular conductor would be a good approximation to a litz wire, IF you specify that eddy-currents are NOT induced in the conductor. Would you agree? And can you give a reasoning behind the statement? As for the cross section, it depends on the effects...