what is an across the line starter

• Across-the-line or Full Voltage Non-Reversing (FVNR) is the most commonly used general purpose starter. ...
• The Reversing Starter or Full Voltage Reversing (FVR) reverses a motor by reversing any two leads to the motor. ...
• The Multispeed Starter is designed to be operated at constant frequency and voltage. ...

More items...

Full Answer

What is an across the line motor starter?

What is an across the line 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. Click to see full answer.

What is a direct on line starter?

A DOL starter (or Direct On Line starter or across the line starter) is a method of starting of a 3 phase induction motor. In 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. Despite this direct connection, no harm is done to the motor.

What is a starter and how does it work?

A Starter is a device that controls the use of electrical power to equipment, usually a motor. As the name implies, starters "start" motors. They can also stop them, reverse them, and protect them.

What is the proper way to reference a full voltage starter?

What is the proper way to reference a full voltage (across the line) starter, in terms of abbreviation, ACL or ATL? Although, from the electrical standpoint, this type of device is called FVNR (full voltage non-reversing) sometimes we call them "across-the-line".

What does across the line starter mean?

What are the two types of starters?

What is an across the line contactor?

What are the three types of starter?

What is an electrical starter?

What do starters do?

What is an across the line controller?

Are contactor contacts wired like a load or a switch?

How does a wye delta starter work?

What are the four types of starters?

What is 2point starter?

What is manual starter?

What is a direct on line starter?

Direct on line starters are commonly used to start small water pumps, conveyor belts, fans, and compressors. In the case of an asynchronous motor (such as the 3-phase squirrel-cage motor) the motor will draw a high starting current until it has run up to full speed.

What is the wiring diagram for a DOL starter?

The wiring diagram for a DOL stater is shown below. A direct online starter consists of two buttons, a GREEN button for starting and a RED for stopping purpose of the motor. The DOL starter comprises an MCCB or circuit breaker, contactor and an overload relay for protection. These two buttons, i.e. Green and Red or start and stop buttons control the contacts.

How many poles does a contactor have?

A contactor can be of 3 poles or 4-poles. Below given contactor is of 4-pole type. It contains three NO (normally open) contacts that connect the motor to supply lines, and the fourth contact is “hold on contact” (auxiliary contact) which energizes the contactor coil after the start button is released.

How does a DOL starter work?

The working principle of a DOL starter begins with the connection to the 3-phase main with the motor. The control circuit is connected to any two phases and energized from them only.

What is a DOL starter?

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. Despite this direct connection, no harm is done to ...

What are the disadvantages of a DOL starter?

The disadvantages of a DOL starter include: High starting current (5-8 times of full load current). DOL Starter causes a significant dip in voltage, hence suitable only for small motors. DOL Starter reduces the lifespan of the machine. Mechanically tough.

What is overload relay?

So overload relays are employed to limit the amount of current drawn. But that does not mean that protects the short circuit. Fuse or MCB used in the system protects the over current. Overload protection opens a circuit at relatively low currents that are a little higher than the rating of the motor.

What is a motor starter?

A motor starter is an electrical device that is used to start & stop a motor safely. Similar to a relay, the motor starter switches the power ON/OFF & unlike a relay, it also provides a low voltage & overcurrent protection.

What is a push button starter?

This type of starter operates manually and does not require any experience. A push-button is used to turn OFF & ON the motor connected with it. The mechanism behind the button includes a mechanical switch that breaks or makes the circuit to stop or start the motor.

What is a reduced voltage starter?

The most common type of starting technique is to reduce the voltage at the starting of the motor to reduce the inrush current that could damage the windings of the motor & also cause a huge dip in voltage. These starters are used for high rated motors.

Why is the voltage across a motor minimum?

Therefore the voltage across the motor is minimum (in safe level) due to the voltage drop across the resistor. The low stator voltage limits the starting inrush current that can damage the motor windings.

What is a stator resistance starter?

Stator resistance starter uses the RVS (reduced voltage starter) technique to start a motor. External resistance is added in series with each phase of a 3 phase induction motor’s stator. The resistor’s job is to reduce the line voltage (subsequently reducing the initial current) applied to the stator.

What is the function of the start and stop buttons on a motor?

The start and stop push buttons connected to the motor and starter can be used for ON and OFF operation of motors.

How does a slip ring motor work?

It works only on a slip ring induction motor that is why it is also known as a slip ring motor starter. External resistances are connected with the rotor in star combination through the slip ring. These resistors limit the rotor current & increase the torque. This, in turn, reduces the starting stator current.

Do you need a VFD for a soft starter?

Typically larger motors can be used if started otherwise. A soft starter may be all that's needed, no need for a VFD. Every utility is a bit different, and the answer for one won't apply for the next, you need to have the conversation with them.

Is POCO single phase?

Yes, this is a single phase service. I only mention "all the amps we want" because the POCO is willing to install a 100kva transformer which is a lot more power than 10HP. They mentioned a willingness to install whatever size transformer we desire.#N#I would like to have the conversation on motor starts but I have already talked with the lead engineer that designs the entrances and he is not amendable to alternative solutions. I see no way around this other than to bend the rule and see what happens, thus my reason for asking about inrush and such. I fear prodding them for more info on VFDs will only lead to them monitoring the system more closely.

Why use a direct on line starter?

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. The maximum size of a motor allowed on a direct on line starter may be limited by the supply utility for this reason.

What is a motor starter?

Motor starters. See also: Motor soft starter. A small motor can be started by simply connecting it to power. A larger motor requires a specialized switching unit called a motor starter or motor contactor.

What is auxiliary contact in starter?

Starters using magnetic contactors usually derive the power supply for the contactor coil from the same source as the motor supply. An auxiliary contact from the contactor is used to maintain the contactor coil energized after the start command for the motor has been released.

How does a soft starter work?

Reduced-voltage or soft starters connect the motor to the power supply through a voltage reduction device and increases the applied voltage gradually or in steps. Two or more contactors may be used to provide reduced voltage starting of a motor. By using an autotransformer or a series inductance, a lower voltage is present at the motor terminals, reducing starting torque and inrush current. Once the motor has come up to some fraction of its full-load speed, the starter switches to full voltage at the motor terminals. Since the autotransformer or series reactor only carries the heavy motor starting current for a few seconds, the devices can be much smaller compared to continuously rated equipment. The transition between reduced and full voltage may be based on elapsed time, or triggered when a current sensor shows the motor current has begun to reduce. An autotransformer starter was patented in 1908.

What type of starter is used for a large motor?

Very large motors running on medium voltage power supplies (thousands of volts) may use power circuit breakers as switching elements. 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.

What does the green button on a motor do?

It insists that the green button is pressed to start the motor. The green button switches on a solenoid which closes a contactor (i.e. switch) to primarily power the motor. It also powers the solenoid to keep the power turned on when the green button is released.

How long does a series reactor carry a heavy motor?

Since the autotransformer or series reactor only carries the heavy motor starting current for a few seconds, the devices can be much smaller compared to continuously rated equipment.