Induction motor Definition and 131 Threads

hi guys, am working on variable speed drive system. My aim is to make a low cost drive system for three phase induction motor. Current system employs three phase AC-DC and DC-AC converters, which has 12 switches in total. I have one idea...i found three phase inverter topology which has 4...

Say you wanted to run an induction motor from a battery without putting dirty harmonics into it. Would a really clean way to do it, to be by using a higher phase number inverter, then transformer, then into the motor? For instance, a 6 phase inverter, into a 6 phase to 3 phase transformer, then...

Homework Statement I studied that as the single phase motor speeds up the backward induced field currents are larger than the forward field currents. So , the corresponding opposing rotor mmf causes backward field to be greatly reduced whereas the smaller forward currents leads to enhancement...

In a 3 phase induction motor,when stator rmf rotates, it cuts the rotor bars and induces an emf in them. Is this emf sinusoidal? I mean shouldn't it be a square wave since the rotor "bars" are being cut by the flux, like in case of concentrated stator windings of a synchronous generator? If the...

Homework Statement Homework EquationsThe Attempt at a Solution Stator Line voltage 220 164 112 88 42 Stator Line Current 6.8 5.4 3.9 3.8 3.7 Stator power 470 360 278 244 232 By plotting a suitable graph from these results, determine the total of windage and friction...

in induction motor there is air gap between stator and rotor. the air gap needs to be as small as possible. but some air gap is needed for mechancial reasons. i understand that a big air gap would reduce power factor as you'd need more magnetizing current. but are there any advantages of big...

Single phase motor is not self starting, so it is started using some arrangement and the starting arrangement is disconnected(not always) once the motor is set in proper motion(about 70% of the maximum speed). But I didn't understand this graph. From the starting moment, motor accelerates and...

Just a curiosity about what happens to the flux, when you short circuit an induction machine. Say there is an initial flux and you're rotating the shaft of an IM and then you short circuit the stator, so no doubt you'll get large currents in the stator, but those large currents, will they cause...

I've studied a 2-pole IM with its winding diagram and understood how the two poles are formed. But I'm struggling to understand the same thing about a 4-pole motor. How does this winding arrangement result into 4 poles?

I am learning basic motor control and there is a formula list in my book. The last one is for torque calculation, can anyone point out to me where this one is from or how is it derived?

I know that decoupling the 3 phase currents we get the id and iq (in rotor frame) currents which control the flux and torque respectively. But where does the relation come from?

I am new to flux oriented control and i read that this method is to decouple the stator current, one component for flux producing and other for torque,so that so that we can control these two current components to control an AC motor like a DC one(right?) However when i try to dig into detail...

Capacitor-start induction motors use a capacitor in series with the start winding to create torque to start the motor. After the motor gets nearly up to full speed, a switch takes the capacitor out of the circuit. I understand the torque is caused by the phase shift created by having the...

It is observed that the stator current of IM increases on loading. In transformers, the increase in primary current due to loading is significant . Is it same in induction motor? Does the air gap affect it?

is there anyone who knows a company that can design single phase induction motor prototypes in the UK..Thanks for your help

Homework Statement I came across these two equations in a chapter on induction motors, and I was wondering if they both calculate the same thing? ##w_r=sw_s## ##w_r=w_s - \frac{p}{2}w## Homework Equations The Attempt at a Solution s is the slip, ##w_r## and ##w_s## are the rotor and...

I want to known the stator design of an indiction motor. How may turns required for each pole. For exmple if a single phase motors is designed to run at 230v ac, how may turns required in each pole. If the same motor is designed to be run in lower voltage (say 110v ac or 12v ac) what will be the...

Hi everyone... I have to design a single phase induction motor. I have some questions and it would be great if you could help me. The parameters I have for the design of the motor are: rated power, rated voltage, frequency, rated speed, power factor, efficiency, full load current and full load...

Hi everyone, I am facing some problems in performing clarke-park transform for an induction motor(4 pole stator, squirrel cage IM). The motor is run with three sine wave inputs, 120 degrees phase shifted with each other. I am measuring the rotor position from the encoder and using twice of...

It is said that crawling occurs mainly due to 7th harmonic component. Due to 7th harmonic the speed decreases by the ratio of 7. However speed is directly proportional to frequency. So speed should get multiplied by a factor of 7 instead. Should the change in frequency affect the number of poles...

Hi, If the voltage, full load current and full load output power (kW) of a 3 phase induction motor are known, and the efficiency is assumed to be 90% (is this realistic), am I correct in thinking that the full load power factor can be approximated (due to assumed and not actual efficiency) as...

Hi, Is there a difference in efficiency between a three phase motor and a single phase motor, in terms of power in against power out. If so, could you please explain why one is more efficient than the other. The reason I ask is because I'm researching the development of the induction motor for...

Hope I can get some help here. I have a 1-1/2 hp. 115/230 volt single phase induction motor I want to use as a small generator. currently it's wired for 115 volt I need help with the math to calculate the proper capacitor/s to use. Running no load amps as a motor draws 18 amps. Name plate...

I want to design a single phase induction motor (1/3 HP,50Hz,220V). I face a problem to design the main dimension of stator and Slot shape and Rotor skew angle . Would you give some idea for design ? or any related book and software ?

Hi, I'm really stuck on this assignment question and could do with a hand on the step by step process of how to get the answers. A three phase induction motor as 2 poles, a standstill voltage of 121 v/phase (Er), rotor resistance of 0.15Ω/phase (Rr) and a standstill rotor reactance of...

Hello! This is my second post about sequence reactances. This time- its in induction motor. To my understanding ( once again ) - In any network (symmetrical or unsymmetrical) , there would be 3 components- positive sequence component, negative sequence component and zero sequence...

Homework Statement A three phase cage rotor induction motor running at full load draws a stator current of 60A at a power factor of 0.8 lagging from a 415v, 50Hz Supply. Under the conditions the stator loss is 3.6kW, the rotor loss is 1.3kw and percentage slip is 4.5%. If the shaft power...

Hello all My question is: Induction motor with nominal load rotates with nominal speed. How the slip will be changed if we decrease input voltage in 10%? I think that if we decrease the voltage, than the current will be decreased also. Than, the moment will be decreased and mechanical...

Homework Statement I can not understand this question: "Describe the characteristics of a three-phase induction motor?" Does it mean speed,torque,etc? Thanks Homework Equations The Attempt at a Solution

Hi. Having measured an induction motor on no load and obtained a torque figure, I have noticed that when load is increased, the torque continues to decrease. How it this possible as I am observing a reduction in rotor speed and increase in rotor currents and current drawn from supply?

Hi, Does anyone know or could help me understand the reasoning for the amount of slip within an induction motor decreasing with frequency under the same load conditions? I.e. For no external load, the slip is higher at 50Hz than at 20Hz etc? Thanks

Hi, I am currently simulating a 3 phase induction motor system. One of the tests that I have run is to keep the motor parameters (reactance, resistance etc.) constant, and then change the frequency of the supply (50, 40, 30 Hz etc.) before measuring input parameters (current and power drawn...

Hi, When a load is applied to the rotor of an induction motor, the rotor speed decreases and as a result, the induced currents in the rotor and the torque produced increases due to the relative speed difference between the rotor and the rotating field within the stator. My question is...

Hello Everybody, Can anyone explain, what is thee difference between 'electrical spped' and 'mechanical speed' of rotor in an induction motor? what do they signify? Many literatures say that electrical speed is no of pole pairs times mechanical speed, if somebody can explain... Thanks

Hello I'm doing a question in induction motor now. formula for Induced torque is Pgap / Ws. i have found the Pgap, but in order to find Ws, i need frequency to find ns.. so my question is, how to find frequency with only given 10hp and four pole

I'm planning on building a simple induction motor for my class project and am hoping someone might have some advice about powering the motor. I feel a little ridiculous asking but I had almost no understanding of electricity prior to the beginning of my Physics 212 class and the textbook doesn't...

Hi all I am trying to understand the concept of 3 phase wound rotor induction motor. I understand why when you feed in 3 phase current to the stators that are separate spatially 120 degree will get you a rotating magnetic field. However, I am having much trouble in understanding the...

Hello. I have to do an experiment on this topic, but there are many things I don't know. First of all, can you tell me what do the symbols V~ and A~ mean?

Hi Sir, I have seen in many IEEE magazines that, a six phase induction motor is having two 3 phase windings spatially separated by an angle of 30 degrees electrical. I have attached the 6 phase induction motor diagram. But I am not able to understand how the motor operates i.e. how the rotor...

3 PHASE INDUCTION MOTOR A 15 hp/230V, three phase induction motor has a full load current of 42A per terminal. 15HP= 11kW find: a) Full load kVA input b) If the full load power factor is lagging 0.85, what is the kW input. My question: How do I know whether its connected Wye or Delta?a) kVA=...

I am doing project on open loop v/f control of three phase induction motor. How to decide the frequency and amplitude of triangular wave(carrier wave) for sinusoidal PWM ?

Hello, I'm trying to find out how much energy an induction motor pulls over a 24 hour period when connected to a resistive load. The only data I have are the specifcations of the motor, so I can estimate how much energy it will draw based on what capacity it might be running at. Really...

Under no load, does an induction motor run exactly at its synchronous speed (i.e. relative field speed) or at a speed that is close to the synchronous speed but slightly less? Thanks for your time.

an 8 pole 3 phase alternator is coupled to a prime mover running at 750 rpm.it supplies an induction motor which has a full load of 960rpm find the number of poles of the motor and the slip i think the induction motor would work as a generator we can find slip by usin s=(ns-nm)/ns where...

I have been tought several times that if an asynchronous induction motor is overloaded, so that the rotor speed goes below where the maximum torque point is, the motor will become unstable, and simply stall, even if you unload it. Why does it do that? fx. here...

Hi all, I would like to install Capacitor Bank into my control panel board which contains of few 10HP induction motors. Currently I'm just able to measure the Ampere for every induction motor by using current meter. How to calculate the reactive power for 10HP 3phase 4pole induction motor by...

I want to learn about Induction Motors in detail (down to construction and design). But I currently want to emphasize on single phase induction motors and their design. I will be involved in motors repair works, so given a blank iron core of a motor, I want to be able to select wire sizes and...

Hello this is my first post, please let me know if I'm breaking any rules, I'm still a bit hazy on them. I am in the process of making a permanent magnet induction generator from and old washing machine induction motor. The motor is rated 1725 rmp, 115 volts 6.3 amps at 1/3 horsepower. It is...

I want to get a larger flow rate out of a common 3 speed induction motor desk fan. Without forking out for an off the shelf VFD, I thought perhaps I could build a frequency doubler using a bridge rectifier. Following the circuit from left to right, I'm thinking that I'll feed the 240V...

Dear friends, 3 phase ind motor is overheated and also tripped during operation. The heat over the induction motor is extremely hot. What will be the reason? Is it due to coil damage inside of motor.? Kindly reply, thank you!