Quick Answer: Why We Use DOL Starter?

How does a motor starter work?

Motor starters consist of two devices—a contactor that completes the circuit to the motor and an overload relay that monitors the current the motor is drawing.

When a condition occurs that causes the motor to exceed the maximum load, the device opens the motor starter control circuit and the motor is turned off..

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.

How does DOL starter reduce starting current?

Direct-on-Line (DOL) Starter This heavy current reduces as the motor accelerates to its rated speed. If induction motor is connected directly to the supply, the starting current will not damage the motor unless it is started and stopped repeatedly over a short span of time.

What is meant by DOL starter?

A direct on line (DOL) or across the line starter applies the full line voltage to the motor terminals. This is the simplest type of motor starter. A DOL motor starter also contains protection devices, and in some cases, condition monitoring.

What are the types of starter?

Based on the above techniques, the most common types of starters are listed below.Stator resistance starter.Auto transformer starter.Star-delta starter.Direct on-line starter.Soft Starter.

How do I choose a DOL starter?

As per above chart:Type of Contactor = AC7b.Size of Main Contactor = 100%X Full Load Current (Line).Size of Main Contactor = 100%x6 = 6 Amp.Making/Breaking Capacity of Contactor = Value above Chart x Full Load Current (Line).Making/Breaking Capacity of Contactor = 8×6 = 52 Amp.

How many types of starters are there?

twoThe two main types of starters are Manual Starters and AC Magnetic Motor Starters, commonly known as Motor Starters. The manual starter is operated manually.

What is VFD starter?

Benefits of choosing a soft starter A variable frequency drive (VFD) is a motor control device that protects and controls the speed of an AC induction motor. A VFD can control the speed of the motor during the start and stop cycle, as well as throughout the run cycle.

What is Star Delta Connection?

Star and Delta Connections are the two types of connections in a 3 – phase circuits. A Star Connection is a 4 – wire system and a Delta Connection is a 3 – wire system. … In a three – phase system, we have a minimum of three conductors or wires carrying AC voltages.

When should I use DOL starter?

Direct On Line Motor Starter (DOL) is suitable for:A direct on line starter can be used if the high inrush current of the motor does not cause excessive voltage drop in the supply circuit. … DOL starting is sometimes used to start small water pumps, compressors, fans and conveyor belts.

Why we use star delta starter rather than DOL starter?

But they also reduce the starting torque to about 33%. This method can only be used with induction motors that are delta connected to the supply voltage. If the changeover from star to delta takes place at too low a speed, this can cause a current surge which rises almost as high as the corresponding DOL value.

What are the advantages of DOL starter?

Advantages of DOL Starter The advantages of a DOL starter include: Simple and most economical starter. More comfortable to design, operate and control. Provides nearly full starting torque at starting.

What is the difference between DOL and star delta starter?

DOL means the motor is connected Directly ON Line using one contactor with no starting circuit to lower the high starting current. Typically the Delta part of Star-Delta. Star-Delta uses two contactors, one to start at a lower voltage in Star and one to run at a higher voltage in Delta configuration.