Electro 8
ELECTRO-TECHNOLOGY
(EEE111)
EXPERIMENT 8
DIRECT-ON-LINE (D.O.L) STARTER
OBJECTIVES
1. To understand the function of contactor, push button, switches and overload protective devices used in direct-on-line starter. 2. To understand the wiring diagram, the inspection and the testing method of the D.O.L starter 3. To understand the steps and safety to power up the signal-phase motor by the D.O.L starter
LIST OF REQUIREMENTS
EQUIPMENT
1. Insulation tester
COMPONENTS 1 Wire connectors 2 Push button switch (2 units) 3 Push-off 4 Single phase motor 5 Contactors 6 Thermal overload relay
THEORY
INTRODUCTION TO D.O.L STARTER
D.O.L starter is a widely-used starting method of electric motor. there are many type of motor starter, the simplest of which is the DOL starter.
The D.O.L starter comprises a switch and an overload protection relay. The switch may be manually operated load break switch or circuit breaker, but more commonly it would be an electromagnetic contactor which can be opened by the thermal overload relay under fault conditions.
Typically, the contactor will be controlled by separate start and stop button. An auxiliary contact on the contactor is used across the start button, as hold in contact. i.e the contactor is electrically latched closed while the motor is operating.
PROCEDURE 1 Draw the wiring diagram for the D.O.L starter figure 8.2 based on schematic diagram of figure 0.1 2 Carry out the wiring for D.O.L starter as done in figure 8.2. 3 Carry out the insulation, continuity and polarity test for D.O.L starter system, and complete table 0.1 4 Energize the D.O.L starter with a single-phase 240V,50Hz supply for the circuit functionality.
THIS MUST BE DONE BY THE SUPERVISOR/TECHNICIAN IN CHARGE
RESULT Insulation test | Phase & neutral | Phase & CPC | Neutral & CPC | | 20A | 144.7MΩ | 109.7MΩ | 105.7MΩ | | 6A | 140.9MΩ | 180.0MΩ | | Continuity test | Phase
(EEE111)
EXPERIMENT 8
DIRECT-ON-LINE (D.O.L) STARTER
OBJECTIVES
1. To understand the function of contactor, push button, switches and overload protective devices used in direct-on-line starter. 2. To understand the wiring diagram, the inspection and the testing method of the D.O.L starter 3. To understand the steps and safety to power up the signal-phase motor by the D.O.L starter
LIST OF REQUIREMENTS
EQUIPMENT
1. Insulation tester
COMPONENTS 1 Wire connectors 2 Push button switch (2 units) 3 Push-off 4 Single phase motor 5 Contactors 6 Thermal overload relay
THEORY
INTRODUCTION TO D.O.L STARTER
D.O.L starter is a widely-used starting method of electric motor. there are many type of motor starter, the simplest of which is the DOL starter.
The D.O.L starter comprises a switch and an overload protection relay. The switch may be manually operated load break switch or circuit breaker, but more commonly it would be an electromagnetic contactor which can be opened by the thermal overload relay under fault conditions.
Typically, the contactor will be controlled by separate start and stop button. An auxiliary contact on the contactor is used across the start button, as hold in contact. i.e the contactor is electrically latched closed while the motor is operating.
PROCEDURE 1 Draw the wiring diagram for the D.O.L starter figure 8.2 based on schematic diagram of figure 0.1 2 Carry out the wiring for D.O.L starter as done in figure 8.2. 3 Carry out the insulation, continuity and polarity test for D.O.L starter system, and complete table 0.1 4 Energize the D.O.L starter with a single-phase 240V,50Hz supply for the circuit functionality.
THIS MUST BE DONE BY THE SUPERVISOR/TECHNICIAN IN CHARGE
RESULT Insulation test | Phase & neutral | Phase & CPC | Neutral & CPC | | 20A | 144.7MΩ | 109.7MΩ | 105.7MΩ | | 6A | 140.9MΩ | 180.0MΩ | | Continuity test | Phase