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Why is the starting torque of a wound -rotor motor higher per ampere of starting current than that of a squirrel cage motor?
The starting torque of a wound-rotor motor is higher per ampere of starting current than that of a squirrel cage motor due to the ability to control the rotor resistance. In a wound-rotor motor, external resistance can be added to the rotor circuit, allowing for increased torque production during startup without drawing excessive current. In contrast, squirrel cage motors have a fixed rotor resistance, which limits their starting torque and results in a relatively lower torque per ampere of starting current. This design feature enables wound-rotor motors to provide better performance in high-torque applications.
How many types of 3-phase induction motors are there?
One way is to add a capacitor and some extra field windings. Starters are needed because the starting current in an motor may go as high as 6-7 times its rated current. Some of the methods used for starting motors are, Direct online starters, Auto transformers, Soft Starters, Variable Speed Drives, Intelligent Motor Controls.
Disadvantages of a squirrel cage motor?
Squirrel Cage Induction Motor Disadvantages:Some of disadvantages or demerits of squirrel cage induction motors are listed below:Main disadvantage of squirrel cage induction motor is that they have poor starting torque and high starting currents. Starting torque will be in the order of 1.5 to 2 times the full load torque and starting current is as high as 5 to 9 times the full load current. In slip ring induction motors, higher starting torque can be attained by providing an external resistance in the rotor circuits during starting of the slip-ring induction motor. This arrangement in slip-ring induction motors also reduces the high inrush currents during starting of induction motor.Squirrel cage induction motors are more sensitive to the supply voltage fluctuations. When the supply voltage is reduced, induction motor draws more current. During voltage surges, increase in voltage saturates themagnetic components of the squirrel cage induction motor.Speed control is not possible in squirrel cage induction motor. This is one of the major diadvantages of squirrel cage induction motors.The total energy loss during starting of squirrel cage motor is more compared to slip ring motors. This point is significant if the application involves frequent starting
What type of current is used in an electirc motor?
Well that depends on the type of motor. DC motors use direct current DC and induction motors use alternation current AC.
Does current flow in all AC motors alternate direction?
Yes, in alternating current (AC) motors, the current flows in alternating directions. This is due to the nature of AC power, where the voltage periodically reverses direction, causing the current to do the same. This alternating current creates a rotating magnetic field that drives the motor's rotor. In contrast, direct current (DC) motors have current that flows in a single direction.
What are the reasons for connecting resistance in the rotor circuit when starting wound rotor induction motors?
To limit the starting current in slip ring induction motors.
How many percent will be the starting current for motor?
Motor starting current is typically 5-7 times the rated current of the motor. (For three phase induction motors)
Where theSlip ring induction motors are used?
The slip ring induction motors are usually used in the application requiring the low starting current or the high starting torque.
What are dc drives main functions?
DC drives are direct current motors. They are lower in cost and easier to control as compared to AC drives, which are also known as alternating current motors.
What is a disadvantages DOL or direct online starter?
it can not be use for heavy duty motors as well as it requires a high starting current.
Why resistance in series won't control speed in dc shunt motors?
because current is same in series resister
Why is the starting torque of a wound -rotor motor higher per ampere of starting current than that of a squirrel cage motor?
The starting torque of a wound-rotor motor is higher per ampere of starting current than that of a squirrel cage motor due to the ability to control the rotor resistance. In a wound-rotor motor, external resistance can be added to the rotor circuit, allowing for increased torque production during startup without drawing excessive current. In contrast, squirrel cage motors have a fixed rotor resistance, which limits their starting torque and results in a relatively lower torque per ampere of starting current. This design feature enables wound-rotor motors to provide better performance in high-torque applications.
Which motor has high starting tourque?
Series motors have the highest starting torque. The torque is proportional to the square of the current, and the starting current is so high it has to be limited by a resistor called a rheostat. Series motos are used mainly on trams and trolley buses.
How many types of 3-phase induction motors are there?
One way is to add a capacitor and some extra field windings. Starters are needed because the starting current in an motor may go as high as 6-7 times its rated current. Some of the methods used for starting motors are, Direct online starters, Auto transformers, Soft Starters, Variable Speed Drives, Intelligent Motor Controls.
Disadvantages of a squirrel cage motor?
Squirrel Cage Induction Motor Disadvantages:Some of disadvantages or demerits of squirrel cage induction motors are listed below:Main disadvantage of squirrel cage induction motor is that they have poor starting torque and high starting currents. Starting torque will be in the order of 1.5 to 2 times the full load torque and starting current is as high as 5 to 9 times the full load current. In slip ring induction motors, higher starting torque can be attained by providing an external resistance in the rotor circuits during starting of the slip-ring induction motor. This arrangement in slip-ring induction motors also reduces the high inrush currents during starting of induction motor.Squirrel cage induction motors are more sensitive to the supply voltage fluctuations. When the supply voltage is reduced, induction motor draws more current. During voltage surges, increase in voltage saturates themagnetic components of the squirrel cage induction motor.Speed control is not possible in squirrel cage induction motor. This is one of the major diadvantages of squirrel cage induction motors.The total energy loss during starting of squirrel cage motor is more compared to slip ring motors. This point is significant if the application involves frequent starting
How do you calculate starting current of 380 volts 3phase 50 hertz AC motor?
Dear Sir,I want to know that how much draw starting current of 380 volts 3 phase 50 hertz AC motors as per rating values?
What are the Applications of induction motors?
Introductionl It is becoming very popular the utilization of squirrel cageinduction motors with variable frequency drives (VFD's) in theindustry.l The advance of power electronics technology and the cost of theVFD's are making this utilization possible.l The many advantages of this type of application are:ÙSpeed variation.ÙHeavy load inertia starting.ÙHigh starting torque requirements.ÙLow starting current requirements.ÙHigh efficiency at low speed.ÙHigh power factor.l The induction motor with VFD's replaces with advantage todaythe DC motors, and wound rotor motors.
