Harsh Power Control

To start a three-phase induction motor or a phase pump traditionally, a Dol panel (Direct online) is used. A full line voltage is applied to the motor terminals by that?DOL?panel starter. Simple, classic, and cost-effective: the?DOL panel. As a result, its easier to use and control Because DOL starters are classics, troubleshooting them is a cinch. The is the most basic kind of induction motor starter. A circuit breaker, contactor, and an overload relay are all included in the Direct on-Line Motor Starter?(DOL). Under fault circumstances, the thermal overload relay might open the electromagnetic contactor.

In most cases, the contractor is operated by two buttons: a start button and a stop button, and hold in contact is connected to an auxiliary contact on the contactor. In other words, when the motor is running, the contactor is electrically locked shut.

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Description

Dimensions and characteristics of the DOL panel

Direct on-line Starter Principles

When the contactor is first turned on, the windings get the entire line voltage. For a brief while, the motor will draw a high inrush current due to the magnetic field in the iron, but after that, the motors Locked Rotor Current will restrict the current. When the motor reaches Locked Rotor Torque, the acceleration begins. To see a considerable reduction in power, youll need to crank up the motors speed to roughly 85-75% of the motors synchronous speed. Motor design and terminal voltage determine the beginning current curve, which is completely independent of the motor load The time it takes for the motor to accelerate to full speed and hence the duration of the high beginning current will be affected by the motor load, but not the size of the starting current. At all speeds throughout the start-up cycle, if the motors torque exceeds the load torque, the motor will attain maximum speed. At any point in the start cycle, if the motors torque output is less than the loads torque, the motor will cease accelerating. If a DOL starters starting torque is inadequate, a new motor with a greater starting torque must be installed. The acceleration torque is the motor torque minus the load torque, and it changes as the motor accelerates according to the motor speed torque curve and the load speed torque curve. The accelerating torque and the load inertia affect the start time.
DOL Panel
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