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What are components of a DC motor starter that can be affected by a high starting current if it is not limited?
armature
What will be the starting current of a 335hp Sqcage motor on no load?
Across the line starting of a motor can be as high as 300% of the full load amps.
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 voltage drop for starting motor current and how to get the starting pf?
How do you calculate voltage drop for starting motor current
What is the need for starters?
for protection from initial currents and short circuit,overload currentsFurther ExplanationWhen a motor is stationary, the only opposition to current flow is the resistance of its windings. When the motor starts to turn, it generates a back emf. So, on starting, the current is high, and it reduces in value as the machine runs up to speed. With larger motors the starting current could overheat and damage the windings, so it is necessary to restrict the value of the starting current using a 'starter'.
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 is the starting current high in DC motor?
The starting current is high because when the motor is not rotating no back-emf is generated, leaving the starting current to be determined by the armature resistance, which should be low.
Why the starting torque of a dc series motor is high?
load is heavier so starting torque is requiredAnswerBecause the same current is passing through both the armature and field windings, the torque is proportional to the squareof the current. Since the starting current is alway high (no back emf), the torque will be very high indeed.
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.
What are the disadvantages of shunt for measuring high current?
When shunts are used in high current measurements, that actual current reading is "extrapolated"(multiplied by a factor then expressed) and variances in shunt tolerance may cause mistaken and less than accurate measurements.
What are components of a DC motor starter that can be affected by a high starting current if it is not limited?
armature
How much current will draw 75000W 400volt at the starting?
At a steady state (when up and running) Watts = Volts x Amps so you just need to solve the equation 75,000 / 400 = ? However, you add the caveat "starting". If your application involves a motor, for example, the starting current will be higher than the steady state current. One rule of thumb says the starting current may be as high as 6 times the running current. This higher current starts high and then decreases as the motor comes up to speed.
Why you use DOL starter in starting of motor?
because of starting current of induction motor is very high and it damages the insulation of motor
What will be the starting current of a 335hp Sqcage motor on no load?
Across the line starting of a motor can be as high as 300% of the full load amps.
What are the disadvantages of z source inverter?
1. more passive elements are required 2. input current ripple is high. Input current is not smooth 3. complex control algorithm
Why motor does not trips on instantaneous current during starting?
If the protection device is bimetalic type then it takes a few seconds to get heated up before tripping off. In case of other advanced type of protection devices, there could be a preset timer to allow a certain amount of high starting current. In both the cases, the avoidence of tripping during starting is by design, since it is known that the motor takes a high starting current.
What are the Advantages and disadvantages of current meter?
disadvantage of current meter
