What is DOL starter PDF?

Description. 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.

What is a DOL motor starter?

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 DOL starter with diagram?

A DOL starter (also known as a direct on line starter or across the line starter) is a method of starting a 3 phase induction motor. In a DOL Starter, an induction motor is connected directly across its 3-phase supply, and the DOL starter applies the full line voltage to the motor terminals.

What is DOL circuit?

The Direct On Line Motor Starter (DOL) consist a MCCB or Circuit Breaker, Contactor and an overload relay for protection. Typically, the contactor will be controlled by separate start and stop buttons, and an auxiliary contact on the contactor is used, across the start button, as a hold in contact.

What is difference between VFD and DOL starter?

As a basic starting method, a DOL starter applies full voltage, current, and torque immediately to the motor after the start command. A VFD converts the AC line voltage to DC voltage, and then inverts it back to a simulated AC voltage for the motor.

Can we use DOL starter for 10 hp motor?

This kind of starter is required to start more than 10 HP motor. Main use of this starter is to reduce the starting current. Due to this reduced voltage starting current is limited. …

Is DOL Star or Delta?

In case of star delta starter the starting current is reduced. It gives the starting current which is about 30% of the starting current provided by DOL. This is also a big advantage of star delta starter….

DOL Starter	Star Delta Starter
Motor starts on its full starting torque	Starts motor on third of its starting torque

Why is DOL starter used up 5 hp?

For a large rating motor, ranging from 5 HP to 25 HP, oil immersed DOL starters are used which provides insulation against sparking on contact points and hence increases the life of starter. DOL starter consists of MCCB, contactor, and overload relay.

Why DOL starter is used up to 5 HP?

Dol is used for up to 5 HP motor. DOL starter connects the motor directly to supply without a reduction in supply voltage and apply full line voltage to 3 phase motor. this is the main disadvantage of dol starter. Small HP motor can be started simply plugging into the power supply.

Which starter is used for 7.5 HP motor?

Three Phase 7.5 HP Motor Starter

Starter Type	Semi Automatic Star Delta Starter
Coil Voltage	220 V
Current Rating	30 A
Phase	Three Phase

What is the Dol starter of induction motor?

Direct online starter DOL diagram DOL starter of three phase induction motors control and power circuit consist MCB or fuse unit which connected in series with the supply. Power contactor, thermal Overload relay for protection and stop and start push button.

What is Dol starter (direct online starter)?

In this article, we will discuss DOL starter (Direct Online Starter) – Working Principle and Construction, DOL Starter Diagram, control diagram, power circuit, and wiring, Single & 3 Phase starter Direct On-Line is the simplest and cheapest method used for starting three-phase motor.

What are the demerits of a Dol starter?

The demerits of dol starter is that gives the highest possible current to motor. Which is 6 to 7 time of rated current of the motor. Besides then DOL starter draws the starting current there also exists a current peak that can rise up to 14 times the rated current since the motor is not energized from the first moment when starting.

Can a DOL motor starter be used as a reverse starter?

DOL Motor Starter can be used, if high starting current cannot cause an excessive voltage drop in the motor circuit. D O L starter use for starting the small motor, compressor, small water pumps, industrial conveyor belts. Fans, air curtains, exhaust fan, blower, etc. A reversing starter can connect the motor for rotation in either direction.