Q:The difference between DC motor and AC motor

AC motor is divided into two categories: asynchronous motor and synchronous motor. According to the number of stator phases, asynchronous motors are divided into single induction motors, two-phase asynchronous motors and three-phase asynchronous motors. The three-phase asynchronous motor is widely used in industry and agriculture production because of its advantages of simple structure, reliable operation and low cost.

Q:A single-phase 240V AC motor has an input current of 4.8A. It is known that the peak voltage waveform occurs 40degrees earlier than the peak of the current waveform. Find the power-factor and the input power. Cheers =)

As the first responder indicated, the power factor value has the same numerical value as the cosine of 40 degrees. This is 0.766 The KVA input is KVA = (E * I) / 1000 KVA = (240 * 4.8) / 1000 KVA = 1.152 The definition of power factor is the ratio of KW to KVA, therefore the formula for the power input (KW) is - KW / KVA = PF KW = KVA * PF KW = 1.152 * 0.766 KW = 0.882432 TexMav

Q:General Electric5k440GT47CL B 40G AMB 103 M3/4 HP 115V 1725 RPM 60 cycles10.0 A 37024400

Your best bet would be to get a voltmeter and use it before you wire it wrong and ruin the motor.

Q:Here is the question: Some motors must be able to switch directions, sometimes spinning clockwise and other times counter-clockwise. For example, the motor in a VCR must fast forward and rewind videotape. In these situations, explain which type of motor is the best choice. Could someone please help me understand? Everyone is saying it's DC, but I don't understand why.

A motor of either type has 2 wires. If an a.c. type motor, it matters not which way round you connect the a.c. supply to the motor: it will always spin the same way. A d.c. motor will reverse its direction of rotation if the wires are switched over.

Q:why ac synchronous superconducting motors are common, not induction superconducting motors?

Superconducting generators and motors are still under research and development.

Q:Soooo... my outside condensor fan has started making this LOUD squealing noise... its like the noise you hear sometimes when it starts up... but it doesn't stop, and gets louder and Louder..like grinding metal.. and it only happens in the winter time when it gets below 45 degrees (F) or so... it works perfectly fine in the summer... The fan spins good and come on fine.. its just the noise..... So what i'm trying to figure out is ... is it the Motor.... or the Fan blades... because the motor is spinning the blades just fine...and with my research i found that when bad fan blades get wet they make a squealing noise..so i thought maybe the same applys with the cold...... or is it the motor with some bad barrings or something... any help??...thanks

First of all, your AC condensor outside should only have the fan come on when the AC is on, not when the heat is on, so why would it be coming on when it is below 45F? Usually the fan is mounted on and directly driven by the motor. Fan blades do not usually make a squealing noise when wet. Most likely the bearings have ran dry and at the very least need lubed. That it's been allowed to run like this for a while (presumably), the bearing may have worn enough that the whole motor needs replaced. Many fans today are considered permanently lubed but that is nonsense, they just don't put a lube hole in to save money and make people buy a new motor sooner. They just need pulled out, the through-bolts removed, and disassembled like this until you have access to the bearings or the felt oil reservoir rings to add a few (several, depending on the motor size) drops of oil. Standard 20wt motor oil, or even 5W20, 5W30, 10W30, etc will do in a pinch. If you have a legitimate need to run the A/C in the winter at 45F which I questioned above, then go with one of the thinner oils like 5W20. The only time the blades should/would squeal is if the nut that secures it to the motor shaft is loose and so the blade assembly is wobbling around.

Q:ac motor tripping on single phase cause?

Motor overloaded, or very low voltage applied (such as using an extension cord with wiring that is too small).

Q:im trying to get two compressors to work of a single pressure switch?thanks a lot!

Assuming both these compressors are supplying the same reservoir, you can use a common pressure switch. But starting current will be well in excess of your 30A. contacts. A better way would be to have the pressure switch supply a heavier current rated contactor, and use the contactor to switch the motors.

Q:i should go with? I need to use them to wind rope that will hold a load of about 30 to 50 pounds. Are these sufficient?Secondly, how can I control the motors. I am new to AC motors and not quite sure how to control them. I would like to implement a micro controller and have it be autonomous. What will I need to do such a system? (preferably as cheaply as possible. )Thanks so much!

You need a gear motor of some sort, preferably a worm drive one, or one with a brake, You don't need the second one, it needs an external gearbox, and with one can probably lift a couple hundred pounds. I'd get one a bit bigger than the first one, which has a worm drive on it, or add a worm drive to that one. To control it, you would use a pair of relays with 10A 120V contacts, and coils appropriate to your control circuit, likely 12V. One relay would power the motor CW, the other CCW, by each applying power to the lead on either side of the run capacitor. For the bigger motor, you would use a 3 phase (preferable interlocking) contactor set. One set of contacts on each section would engage power to the motor, the other two would apply the correct polarity to the start circuit (in relation to the run windings) for the intended direction.

Q:Hello, I'm planning a project and I am going to need to control the rotational speed of an electric motor very accurately. Is there an easy way to do this? I was thinking about some sort of comparative op-amp but don't really understand.Also, I need the motor to be able to change speed very quickly, ie accelerate and decelerate to the required angular velocity. Is this quality the torque? Thanks

If it is an AC motor I would purchase a variable frequency drive from Grainger.