What is DOL starter with diagram?
In the DOL method of starting a squirrel cage induction motor, the motor is connected to the full supply voltage through a starter. The direct-on line starter consists of a coil operated contactor C which is controlled by start (normally open) push button and stop (normally closed) push button.
What is DOL starter PDF?
The Direct on Line motor starter (DOL) is designed to switch a single or three phase induction motor at rated voltage. It comprises an enclosure in steel or plastic, a contactor, start contact, link wires and stop / start buttons. The Thermal overload is supplied as a separate item.
How do you control a DOL starter?
The DOL Starter is started by simply pressing the Start Push button and stopped by pressing Stop push button. This method has easy way of controlling the device. If the push button is pressed, the contactor gets energised and gets closed.
What is the function of control circuit in Dol 3 phase motor?
There are two types of circuits in the DOL starter diagram given above; The control circuit and the power circuit. The Control Circuit: It is powered by only 2 phases of the power supply and it is responsible for starting and stopping the power supplied to the motor.
What is DOL control panel?
Direct On Line start is probably the simplest and traditional type of start and it is to connect the motor directly to the power supply performing therefore a full-voltage start-up. It is often abbreviated with the acronym DOL.
How does a DOL work?
Direct on line (DOL) motor starting is when a motor is started at full load, with full line voltage applied to motor terminals. As this causes the motor to draw a large amount of current, it is only suitable for motor powers up to 4Kw, with a maximum motor size of 10Kw connected this way.
What is the type of control circuit?
Control circuits can be simple two-wire on/off devices that energize a motor starter , or they can be more involved three-wire circuits with multiple pushbutton locations and motors that start in sequence.
What is DOL mode?
Principle of Direct On Line Starter (DOL) The motor will draw a very high inrush current for a very short time, the magnetic field in the iron, and then the current will be limited to the Locked Rotor Current of the motor. The motor will develop Locked Rotor Torque and begin to accelerate towards full speed.
What is a starter panel?
Starters are devices that control the use of electrical power to equipment. As the name implies, starters “start” motors. They can also stop, reverse, accelerate and protect them. Starters are made from two building blocks: contactors and overloads.
What is a starter circuit?
The motor starter has two circuits: the power circuit and the control circuit. The power circuit runs from the line to the motor. Electricity passes through the contacts of a starter, the overload relay and out to the motor. The power (main) contacts carry the motor current.
What are the advantages of Dol starter?
Simple and most economical starter.
What is the range of using Dol starter?
– Dol starter is useful where high starting inrush current does not cause damage to an induction motor. – Dol starter is very useful in motors where 3-phase induction motor is low power rating up to 5 HP. – Application of dol starter is in motors where high starting current does not cause an excessive voltage drop in the supply circuit.
Can any motor start with Dol?
The motor starting technique used here is called full voltage or across the line starting technique where the voltage at motor startup is not reduced. Hence, such a starter cannot reduce the starting inrush current. Therefore, the motors used with DOL starters must be rated below 5 HP. However, they do provide protection against overcurrent.
What is the purpose of Dol starter?
– So that’s why we don’t use DOL starter for MOTOR having higher HP ratings. – It only protects the motor during overload, short circuit condition. – During abnormal conditions Thermal overload RELAY will operate and disconnects the MOTOR from the Supply.