Why we use star delta starter for above 5 hp motor?
Main use of this starter is to reduce the starting current. Due to starting star connection reduces the voltage by 1/ root 3 times. Due to this reduced voltage starting current is limited.
Why we use DOL starter?
The applications of DOL starters are primarily motors where a high inrush current does not cause excessive voltage drop in the supply circuit (or where this high voltage drop is acceptable). Direct on line starters are commonly used to start small water pumps, conveyor belts, fans, and compressors.
What is the difference between DOL and star delta starter?
In the DOL starter, it is possible to start a motor with a simple circuit. This can be further explained that in a Star-Delta starter, the motor is started as a star connection and when the motor starts running the connection is changed to the delta. With star connection, the motor takes times less voltage.
What is torque of a motor?
Torque is defined as rotational force at a distance from the rotational axis. It is measured by units such as lb-in (pounds inch) in imperial or Nm (newton metre) in metric. Torque is just as important, if not more important, than the horsepower of a motor.
What is RDOL starter?
Reverse Direct OnLine starter (RDOL starter) consists of two contactors connecting the power supply to the Motor. The two contactors are complementary to each other and can be used to reverse the direction of the motor. An RDOL reversing starter can connect to the motor for rotation in either direction.
Why do we use star delta instead of DOL?
During a DOL start, the starting torque is very high and is usually higher than required for most applications. The starting torque of a star delta starter is reduced to about 30% of the torque available at a DOL start. Star delta method only works when the application is lightly loaded during the start.
