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because of starting current of induction motor is very high and it damages the insulation of motor
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What is a disadvantages DOL or direct online starter?
it can not be use for heavy duty motors as well as it requires a high starting current.
Do 1 phase electric motors need starters?
it depends on the load and size of the motor if the motor has to drive heavy loads from initial state it require more torque, for this we use star-delta starters where load on motor in permissible then we use a DOL starters DOL starters are direct supply feeders to the motor so there is no rule to use a starter. we can use anything to swith the motor. for protection we need a overload relay and you ask for a 1ph motor, i.e maximum 3hp motors are available for less than 2 hp motor you can use a 6amp switch used in household or a 6amp mcb (includes overload). for 3hp a 16 amp switch or a 10amp mcb is more than enough
What the purpose of starting resistor used in dc motor?
describe how to use starting resistors to star a DC motor
Do you need a starter for a 3 phase 5 horse motor?
YES. USE THE NORMAL DIRECT-ON-LINE OR ACROSS-THE-LINE STARTER.
Why use link in star contactor?
The link in the star contactor is used to form the star point of three of the motor leads. On most star wound motors the star point is inside the motor windings. On a motor that can be used for star delta starting it is a six wire motor. The star point winding depends on the contactor to tie the coil ends together externally in the control panel of the star delta starter.
Can DOL starter use for 50kw motor?
The answer is yes. I had seen 110kW pump start on DOL starter
What is a disadvantages DOL or direct online starter?
it can not be use for heavy duty motors as well as it requires a high starting current.
What is Direct online Starters?
A direct on line starter, often abbreviated DOL starter, is a widely-used starting method of electric motors. The term is used in electrical engineering and associated with electric motors. There are many types of motor starters, the simplest of which is the DOL starter. A motor starter is an electrical/electronic circuit composed of electro-mechanical and electronic devices which are employed to start and stop an electric motor. Regardless of the motor type (AC or DC), the types of starters differ depending on the method of starting the motor. A DOL starter connects the motor terminals directly to the power supply. Hence, the motor is subjected to the full voltage of the power supply. Consequently, high starting current flows through the motor. This type of starting is suitable for small motors below 5 hp (3.75 kW). Reduced-voltage starters are employed with motors above 5 hp. Although DOL motor starters are available for motors less than 150 kW on 400 V and for motors less than 1 MW on 6.6 kV. Supply reliability and reserve power generation dictates the use of reduced voltage or not. A very well-known motor starter is the DOL Starter of a 3-Phase Squirrel-Cage Motor. This starter is sometimes used to start water pumps, compressors, fans and conveyor belts. With a 400V, 50 Hz, 3-phase supply, the power circuit connects the motor to 400V. Consequently, the starting current may reach 3-8 times the normal current. The control circuit is typically run at 24V with the aid of a 400V/24V transformer
How does a dol starter work?
A Direct-On-Line (DOL) starter is an electronic 3-phase motor-control system which offers soft starts in DELTA configuration. DOL starters are now replacing the use of manual or semi-automatic "star-delta" starters.In this way of starting a 3-phase motor, full line voltages are applied to the motor through relays and contactors. The DOL is nowadays the most common type of 3-phase motor starter used.It has a "closing circuit" and an "opening circuit". The closing circuit is for applying the service lines to the motor and the opening - or "tripping" - circuit protects the motor by cutting-off (or "tripping") power to the motor from the service lines if there is any overload condition, a single phasing fault, etc.For more information please see the answers to the Related Questions shown below.
Why using on motor star delta starter?
because at the starting the induction motor drawn a heavy current thats why we use starter to increase the starting resistance of the induction motor!
Can a voltmeter be used to measure voltage in and out of a starter motor?
Voltage flow into a starter motor, never out of it. Use the voltmeter to measure the voltage at the starter motor before starting to crank and then whilst it is cranking. (Before cranking, the voltage appears across the starter motor relay only.)
What is the advantage of a Star Delta Motor Starter?
The inrush current to the starting motor is lower due to the the motor coils being in series across the line creating a higher impeadence. When the starter connects to delta connection the motor is already turning and it does not have to go through the locked rotor phase. This system is being phased out now with the use of electronic soft starts and by-pass contactors.To start a motor direct on line (DOL) in delta requires approximately 6 to 8 times the full load current of the motor and delivers full torque. Delta places 415v across each of the windings on the motor. A Star-Delta starter starts the motor in Star which places 240v across each winding on the motor. This results in a lower starting current and also a lower starting torque.
Can you use star delta starter and soft starter in to same motor?
Probably. More importantly, why would you want to? The Star/Delta starting method is used to minimize motor starting current, just like a soft starter. Use one or the other. There's no good reason to use both, it will just make things more complicated.
How a direct online starter programmed in plc?
DOL starter is a direct online starter... so its PLC programme is as follows: Use a series connecion of 1 NO and 1 NC switch and a motor.. And make a parallel connection of d NO switch with another NO switch.. Addressing: 1 2 3 ------------|\|----------(output) | | | 3 | |----|
Do 1 phase electric motors need starters?
it depends on the load and size of the motor if the motor has to drive heavy loads from initial state it require more torque, for this we use star-delta starters where load on motor in permissible then we use a DOL starters DOL starters are direct supply feeders to the motor so there is no rule to use a starter. we can use anything to swith the motor. for protection we need a overload relay and you ask for a 1ph motor, i.e maximum 3hp motors are available for less than 2 hp motor you can use a 6amp switch used in household or a 6amp mcb (includes overload). for 3hp a 16 amp switch or a 10amp mcb is more than enough
What is the function of liquid in liquid resistance starter?
Combination of water and caustic soda for improving the resistance in starter, that's called Liquid Resistancestarter.If any slip ring Induction motor, at the time of startinggiven the external resistance required to rotor side, why because starting current and starting torque is very high.So we are using resistance starter depend on motor capacity , at that place using Liquid resistance starter.Liquid resistance starter (LRS) ,IN which externalresistance is liquid media which is use for the startingmethod of slip ring motor. For starting of slip ring motor external resistance arerequired so that we use liquid (addition of some causticsoda)as resistance so that is called as LRS.
What does a car need to start?
A charged battery (usually 12 volts) is needed to turn over the starter motor when the ignition key is turned momentarily. The spinning starter motor will start the vehicle's engine. On older vehicles a starting handle could have been used, but modern cars don't use starting handles.
