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Disadvantage of AC Drive?
- Speed Control The main disadvantage of AC motors, when compared with DC motors, is that their speed is more difficult to control. AC motors can be equipped with variable frequency drives, which provide smooth turning moment, or torque, at low speeds and complete control over the speed of the motor up to its rated value. Variable frequency drives improve speed control, but do create losses with reduced power quality. Control Complexity The device used to control an AC motor, known as an AC drive, is typically more complex than that used to control a DC motor. An AC motor controller must convert AC mains electricity to DC, and convert DC back again to an adjustable frequency and voltage output to the AC motor. By contrast, a DC motor has a separate field, or excitation, and power circuits, requiring just a single power conversion from AC to DC -- so the circuitry of a DC motor controller is simpler. Power Torque Historically, another disadvantage of AC motors has been that they develop less power, or less torque, per frame size. Research conducted by Rockwell Automation compared typical, commercial AC and DC motors in industry standard National Electrical Manufacturers Association (NEMA) frame sizes, and found this to be the case. However, AC and DC motors employ different classes of insulation and have different service factors -- the overload capacity at which the motor can operate without damage -- so direct comparison is not always straightforward. Other Disadvantages AC motors are typically more expensive than DC motors for most horsepower ratings. If the rotor of an AC motor rotates faster than the speed command of the AC drive, the motor acts as a generator and pumps, or regenerates, energy into the drive. If the drive cannot absorb this energy, the drive will switch off, or trip, with a fault. AC drives capable of regeneration are more complex and more expensive than DC regenerative drives. AC motors may also produce more audible noise than DC motors.s
Hi, Please i need help on how to convert 12v dc @ 0.12A from an electric motor to 150v Ac @ 2A.?
- Not going to happen. Once you up the voltage your current capacity will go down. P=IxE so 12v X 0.12=1.44 watts but 150v X 2a = 300 watts. so your are short 298.56 watts of power. You need 25A of 12v power to get you 150v AC @ 2A. And that's with no loss in the system.s
How to distinguish AC and DC machines
- This also increases the manufacturing cost of DC motors to a certain extent. The alternator is concerned, it can realize direct energy feedback to the grid (but must ensure 4 conditions: the same voltage amplitude, phase and phase sequence of the same, the same frequency); but DC generator power needs to convert AC inverter (DC rectification process called, the direct current into alternating current the process that the inverter can be feedback to the power grid). So it also needs to increase the power of the inverter.s
How to make the AC motor stop rotating rapidly?
- Electromagnetic brake, load and DC braking or braking circuit of DC power consumptions
What are the speed regulating methods of AC motors? Detailed point
- (1) rotor circuit series resistance: used in AC winding asynchronous motors. The range of speed regulation is small, the resistance consumes power, and the motor efficiency is low. Used of cranes.(2) change the speed of power supply voltage, the speed range is small, the torque decreases greatly with the voltage drop, and the three-phase motor is usually not used. Used for single-phase motor speed regulation, such as fan.(3) cascade speed regulation, in essence, is the introduction of additional rotor electromotive force, change its size to speed. It is also only used in wound motors, but the efficiency is improved.(4) electromagnetic speed regulation. Used only for slip motors. By changing the exciting coil current, stepless smooth speed regulation, the mechanism is simple, but the control power is smaller. Not suitable for long term low speed operation.s
How to run a dc series motor in ac? Will it limit its characteristics?
- hi. AC automobiles are designed and outfitted in a different way than DC automobiles. AC automobiles earnings on the 60 hertz clock of a capability line (or 50Hz in different countries) - this suggests the capability line ameliorations stages 60 cases a 2nd - to rotate, whilst DC automobiles are designed with the voltage point utilized. you are able to administration them the two, yet with different skill. the simplest to regulate is the DC motor (replace the skill (the voltage) and it turns slower or quicker.s
how to wire a bridge rectifier to change a dc motor to ac volts?
- Bridge rectifiers cannot change DC to AC. They will only change ac to dc.s
How to calculate AC motor efficiency at no load?
- Naresh, With the motor on no load, none of the energy being consumed by the motor is being gainfully used, so the efficiency must be zero. You should also remember that with a motor on no load, the power factor is very low.s
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