DOL STARTER CONTROL DIAGRAM
in this article we will study about dol starter control diagram. In case of small rating motors having less than 05HP motors. The starting current is not so very high and these motors can withstand starting current without any starters. Thus there is no need to reduce the applied voltage to control the starting current. Such motors use a type of starters which connects the stator winding directly to the supply without reduction in voltage. therefore the starter is known as DOL (DIRECT-ON-LINE) starters. This starter does not reduce applied voltage but protects from various ways like overloading, under voltage, single phasing etc. the figure shows the dol starter control diagram.
dol starter control diagram
- Magnetic contactors
- Over load relay protection
- No(normally open)
- Nc(normally closed)
Magnetic contactors:- magnetic contactors is an electrically controlled switch used for switching a power circuit similar to relay except with higher current rating. A contactor is controlled by a circuit which has much lower level than the switched circuit. Magnetic contactors consist of a coil which produces magnetic field. The contactors are consist of additional contacts i.e– NO (Normally Open) and NC(Normally Closed).
No(normally open) :- when start button is pressed the motor is on till the Push button is pressed (inching). Therefore NO contact is used in the contactors. NO(Normally Open) contact ensures that the motor remains in ON condition when push button is left.
NC(Normally Closed) :- when stop button is pressed NC (Normally Closed) contact in the contactor breaks the circuit and motor will stop. normally closed push buttons are make the contacts in its default state and breaks the circuit when it is pressed.
Over Load Relay :- over load relay plays an important role for the protection of the motor. over load relay protection is used for the protection of motor against over current, over voltage, over heating and under voltage. It comes with the range of Amperes.
DOL starter physical overview
DOL starter working :-
how dol starter control diagram works
when we press the start button to start the motor the relay gets the phase and circuit completed thus coil energizes and contactors produce magnetic field .the main contactor closes and motor gets the supply and the motor starts.When we press the stop button the circuit will interrupt and the motor stop.
Related articles of dol starter control diagram –
- star delta starter complete theory
- connection of the star delta motor
- single phase induction motor- basic, construction and working
- Three phase induction motor
This video will also help you to better understand the dol starter control diagram
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