# What is Ac motor: Definition and 48 Discussions

An AC motor is an electric motor driven by an alternating current (AC). The AC motor commonly consists of two basic parts, an outside stator having coils supplied with alternating current to produce a rotating magnetic field, and an inside rotor attached to the output shaft producing a second rotating magnetic field. The rotor magnetic field may be produced by permanent magnets, reluctance saliency, or DC or AC electrical windings.
Less common, AC linear motors operate on similar principles as rotating motors but have their stationary and moving parts arranged in a straight line configuration, producing linear motion instead of rotation.

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1. ### Understanding AC Motor Basics: Why a 120V Motor Can't be 3-Phase

I have just started my electrician career and I am studying electric motors. why an 120v ac motor can not be 3 phase ? .
2. ### AC motor rotary capacitor soft start

I was wondering about , have there been or are there any systems that would use a large capacitance rotary capacitor/s as a mechanism for soft start of larger AC motors and also they would serve as power factor correction devices? The idea is basically simple, say one has a 3 phase motor and we...
3. ### What causes an AC motor to pull locked rotor amps?

When an alternating current motor first turns on, what causes an alternating current motor to pull locked rotor amps for approximately one second after first turning on as opposed to just pulling the same amount of amps the entire time? What causes the amperage on an AC motor to drop after...
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### Controlling the speed of an AC motor?

For my IB Physics Extended Essay, I have just changed my topic from momentum to this and I have really little time of doing it... (Due in Oct) :cry::cry::cry::cry::cry::cry: My research question would be The effect of angular velocity of circular motion of a moving sound source on the sound...
5. ### Model AC Servomotor with Dynamic Load Torque

Hi, i want to model an AC Servomotor where i assume that a dynamic load is attached to the shaft of AC Servomotor. the paper that i have attached to this post has ac servomotor model running without load that's why in equation 5 TL(s) (the load torque)=0 . Now i want to include TL(s) in the...
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### Why is my new 1ph AC motor overheating?

Hello all, I'm about at my wits end with this project, so maybe someone with a little more knowledge can help me out? I recently bought a 30" Patterson air cannon fan that came with a Dayton 1hp 3ph ac motor. The whole unit needed to be reconditioned, and the motor needed to be replaced. After...
7. ### Make a Monophase AC Motor Run: 3 Speeds Fan w/ Digital Logic

Hey, everyone, I got this motor from my fan, I am trying to run it but there are a few more wires that I was expecting. Can someone please give me some light? What are all those wires and how to make ir run. PS: 3 speeds fan w/ digital logic on the top (taken off)
8. ### How to control an ac motor with sinusoidal torque output

Hello, guys. In field oriented control of ac machines, the electromagnetic torque is proportional to the q-axis current. We can control instantaneous torque by control the q-axis current. If the torque we want is a constant value,with PI controller, no problem, no steady error. But if we want to...
9. ### What materials do I need to wire a VFD?

Hi everyone, I am part of a senior design group that is building a dynonameter to test shocks. We are ordering parts tomorrow morning and so I want to make sure that I am not missing anything. I do not have any experience with VFD's or three phase motors but I am doing my best to research and...
10. ### I want to replace an AC motor with a DC motor

Ac motor is 1.12 amp 3000 rpm 60 Hz 1/30 Hp sealed ball bearing. I want to use a 12 V dc motor. Any help would be greatly appreciated. Thank you.
11. ### Is 1MW 6kV 1600 RPM Motor Really Worth Only 40 Euros?

Hi... Need help understanding 1MW, 6kV, 1600 RPM,Cage Rotor Asynchronous Motor, 3 Phase, 4 Poles. I have the basic understanding of all ratings but have received very low price for this motor but when i searched on the internet it looked huge and had very high price as compared to what i have...
12. ### Where can I find a controller for a 3 Phase AC motor?

I'm working on a project with a team in building a motor. My task is to find a controller for the motor, but I haven't had much luck. Here are the specs for it : Permanent magnet synchronous motor, 3 phase 8 pole 2 layer winding 100 kw power 400V The motor is AC. If somebody can even point me...
13. ### Device that changes the direction of single phase ac motor?

hi alll...we know that by changing the polarity of phase and neutral , direction of ac motor can be changed. but is there any automated device that does this job? ...
14. ### Powering 10HP 460VAC 3Phase AC Motor: Transformer?

Does anyone of a transformer that can step up 120vac to 460vac? Or do I need to use two transformers and step it up twice? It is powering a 10hp 460vac 3phase ac motor. Thanks.
15. ### Reversing Taifu QB70 single phase AC motor

Hello Guys, I got a Taifu QB70 water pump. But no more in use, I wish to use this motor in a gate opener project of mine. However I cannot figure out how to make the motor rotate in a reverse direction. What I tried ? 1. I reversed the position of the capacitor thinking it would...
16. ### DC brushless motor vs. AC motor

I noticed that common technology such as brushless DC motors use AC to drive them. What exactly makes DC brushless motors different from AC motors if they both ultimately take in AC? Why even refer to DC brushless motors as DC motors if they're not even driven by DC? I understand the source is a...
17. ### Reason and remedy for AC motor overheating?

Hi All I am asking this question as a mechanical engineer, so please bare this in mind if you have the time to post a reply... I have a basic DIY type cement mixer that has given up today. It is a AC 230V model with the most basic of drive setups (pulley and drive belt attached to the...
18. ### 2 vs 4 vs 6 pole AC motor HP

Often I'm reading on other sites that if a 2 pole 3600RPm (synchronous speed) motor were connected so that the ratio would lower the speed to the same as a 4 pole (2X) and so on with 6 pole (3x) the output HP will remain the same. However the larger the number of poles the larger the motor and...
19. ### How to build a simple AC motor with Styrofoam

Hello everyone, For my physics class, I want to build an AC motor with styrofoam, magnets, screws and magnet wire. So far, I have built a cylinder of about 2.5" of radius and 1" in height with eight magnets (strengh 6/10) around it. Each magnet is glued on the side of the cylinder...
20. ### Found a small AC motor and am scared to touch it

I found this motor at a thrift shop and got it for free. I wired it up and found that it pulls a surprising .45 Amps. It also generates an amazingly effective magnetic field around it. I am scared to touch it with both hands. It seems to have a small transformer... Probably makes some mean...
21. ### Help Wiring a 30 HP Toshiba AC Motor - Ian Needs Assistance

I hope someone can help me. I have an old 30 HP motor that I need to get working...if possible. It is a 12 wire Toshiba, dual voltage. 230V 460V. To wire for the low voltage the nameplate says: connect wires 4,8,10 and 2 to supply 1. Wires 9,5,11 and 3 to supply 2 and Wires 6,7,12 and 1...
22. ### Why Use Both Voltage and Phase Control with PWM for AC Motor Speed Regulation?

I want to controll ac motor using pwm.sir told me for that you required volage controller and phase controller.if voltage is controlled by pwm so why i want to use this phase and voltage controller?
23. ### AC motor vs. DC motor efficiency

I am currently using a 600HP DC motor for an extruder application and I am exploring the idea of switching to a 600HP AC motor. What kind of energy savings/efficiency can I expect if any?
24. ### Why is a DC Motor Self-Starting vs. an AC Motor?

Can someone explain me why dc motor is self starting differ of ac who is not self starting motor?
25. ### Low voltage relay and AC motor questions. Heeeelp. Please

Hi, I have a central vacuum system that has blown it's circuit board up. Basically a hoover with a low voltage switching system to fire the motors up. Finding a new board will be difficult so I'm going to rebuild the control system. I can solder, can rewire a house, but the finer points of...
26. ### Automotive Designing a brushless AC motor for Formula Student

I am on a Formula Student team and we have decided to design our own brushless AC motor. Our main issue is how we will cool the motor, since we want to keep weight down while also increasing power output. We will be making the rotor from forged Titanium (Ti6Al4V) and the housing from forged...
27. ### Help w/ Single Phase AC Motor wiring? (not HW)

Hey all. I have an old garage door opener motor. Its a 1/3 HP, 1000 RPM, 115 volt, 3.6 amp, AC Motor (Am I correct in thinking its single phase?). I'm attempting to motorize a grain mill that I have in the kitchen. (the faster I can grind the wheat the faster my wife can make homemade bread...
28. ### AC Motor Suggestions for a new product

Hello community. I am currently working on a product that requires relatively high torque and rpm, around 3 N/m torque and between 150-300 rpm to be specific. My knowledge about motor is very limited and i am running out of time. I understand that i won't find the exact spec and probably will...
29. ### AC Motor Reversing: Is It Possible?

Say I have an AC motor with 100 ft*lbs torque, and I run it against a load of 200 ft*lbs torque so that the motor spins in the opposite direction of the power it is providing. Is this possible, and if so can this condition be sustained over a period of time without damaging the motor?
30. ### How to test AC motor resistance test

How to test AC motor resistance test an continuity test for 3 phase
31. ### Reversing Direction & Overheating Solutions for Single Phase AC Motor

I have an AC Gearmotor W/Fan, Base Mnt, 100 rpm, 7 in-lbs Torque, 115 VAC - I need to achieve 2 purposes with it: 1. Need to able to reverse directions - can I do it with a DPDT? 2. It is overheating - how can I solve it -- heatsinks or fans? Any recommended ones -- I have never done that...
32. ### How are BLAC motors wound and what makes them different from BLDC motors?

Hello, I've recently read a couple of things about brushless motors that have spurred quite a few questions. Googling has solved some of them, but I'm hoping that you can help with the rest :smile: Apparently there are two types of permanent magnet brushless motors - DC and AC. This is...
33. ### Fan AC Motor adaptive use - problem

We have adapted a 60W A/C Fan Motor, 1500 RPM to run two spindles one at 6000 RPM and the other at 500 RPM using pulley & belt. On continuous use the motor heats up excessively and a few fail. Load is winding of threads from a Cone to a bobbin. I need a few suggestion i) Can rewinding...
34. ### Determining power requirements for an AC Motor

I am trying to determine the power requirements for an AC Motor for a Plunger type wave maker. Attached is the layout of the plunger and tank. The formulas that I think might be involved in solving this problem are below: P.E = mgh W= F x d Power= W/time Pressure= F/ area What I...
35. ### Need Suggestions to Control the Position of an AC Motor Using an Inverter

Hi, I'm new in this forum. Nice to meet you all. I'm currently working on a project that uses AC motor. The goal is to make a position control system for the motor. Currently I'm using the Altivar 16 Square D inverter to control the speed of the motor. It uses a logic voltage to control the...
36. ### Single-phase AC motor - winding distribution

Motor: Delco - 1/4 HP - 5.3A - 1735 RPM - single-phase AC; 32 slots - 4 poles - I have run into conflicting terminology, so I apologize for any confusion - Each of the four poles in this motor's stator core contains three coils with two empty slots at the center for a total of eight slots...
37. ### Electromagentic brake for AC motor

Hi, I want to create a electromagentic brake for AC motor. could you let me know how can I calculate wire lengh and what is the gauge of wire. if you have any calculating table please let me know. Regards, Naveen
38. ### AC motor load torque calculation

Hello! Not sure whether it's a right place to post. My question is from a field of electric drives. I can't figure out how to choose an induction motor for a certain load. Load is a simple cylindric flywheel fitted directly on a rotor. Flywheel has a known mass and dimensions. I know...
39. ### Single phase ac motor on dc supply?

ive got a single phase ac motor that runs on 110V and i'd like to run it on a 12v dc source. basically its a transfer pump for a school bus that runs on vegetable oil, and we currently have to find an outlet to plug the pump into every time we go behind restaurants to fill up our tank. id like...
40. ### Troubleshooting Broken AC Motor House Fan: Tips and Tricks

Hi, my brother asked me to troubleshoot his electrical house fan. He tripped over it and then stepped on the fan blade which then caused one of the fan blade rivets to break off. A closer inspection revealed that the rivet did break off, however, the bracket that is attached to the electrical...
41. ### AC Motor from Washing Machine: 11 Wires & Sparks

AC motor from washing machine, has 11 wires from it. Aside from Earth I have no idea what they are however I have observed: If the white+blue OR the red+orange wires are bought into contact then the shaft becomes hard to turn AND I can get a few small sparks by spinning the shaft and quickly...
42. ### Engineering Alternator Problems (3 phase and single phase AC Motor)

Homework Statement 1. A 4MVA, 13.3kV, 60Hz, 3 phase, delta-connected alternator has an effective resistance of 5.2 ohm/phase and a combined armature reactance of 54 ohm/phase. Determine the full-load generated voltage per phase, a. At unity pf, b. at 0.8 pf lagging, and at 0.866 leading pf...
43. ### AC Motor 2900 RPM: Connecting Coils

I have got a fractional h.p. single phase ac electric motor. It was running at 2900 rpm and burned out. The stator has 8 slots and two windings. The first winding has got 4 coils which are inserted from slot no. 1 to 3 , 3 to 5 , 5 to 7,and7 to 1, the second winding also has 4 coils which are...
44. ### Building an electric using a 3 phase 40 hp AC motor

hi im a mechanical engineering student, and we are building an electric using a 3 phase 40 hp AC motor, which is oil cooled. The motor must be submerged in oil that is then circulated... the motor will produce up to 8000W-10000W of heat. does anyone know if it would be possible to use the...
45. ### AC Motor Capacitors: Wiring, Diagrams & Troubleshooting

I picked up a good and cheap AC motor that came with its own capacitors <not wired in though> The capacitors are these http://www.weisd.com/store2/NTEMRC370V7R5.html and this is the diagram on the motor http://foxhole.kicks-ass.net/diagram.jpg" Now I tried putting this together but with no...
46. ### Dayton AC Motor Speed Control: Risks & Solutions

We have one of these Dayton single phase AC motors: http://www.grainger.com/Grainger/wwg/itemDetailsRender.shtml?xi=xi&ItemId=1611576952 And I am wanting to control the speed of the motor. I didn't take very many power classes but from what I remember the motor speed is dependent on the input...
47. ### AC Motor - 120v to 220v static conversion problem

I'm currently working on a senior project that consists of a frequency controlled AC motor that statically converts 120vac out of the wall to 220vac three phase required for the motor. It is a 1/3 HP, 208vac, 2.4A, 1.35SF, 1720 RPM motor. The frequency driver says it is capable for 2.6A 208vac...
48. ### Increasing the speed of an ac motor

Hey. I was doing a question and it asked what would be the graph of an AC motor if the speed was doubled. (the previous period was 10 ms). I think that the frequency would be doubled but would anything happen to the amplitude?