Otsekäivitus

Otsekäivitus, a Finnish term, translates to "direct start" or "direct initiation." It commonly refers to a method of starting an electric motor without any additional starting components like resistors, soft starters, or variable frequency drives. In this configuration, the motor is connected directly to the full supply voltage of the electrical grid.

This method is the simplest and often the least expensive way to start a motor. However, it comes with significant drawbacks. When a motor is started directly, it draws a very high inrush current, typically six to eight times its normal running current. This surge can cause voltage dips in the power supply network, potentially affecting other connected equipment. The high current also places considerable stress on the motor windings and the power system components.

Due to the high starting torque and current, otsekäivitus is generally suitable only for smaller motors or those where the high starting current and its associated issues are acceptable. For larger motors or in applications where controlled acceleration, reduced mechanical stress, or minimized voltage disturbances are required, other starting methods are preferred. These alternative methods, such as star-delta starting, soft starting, or using variable frequency drives, provide a more gradual and controlled start-up process.