THIS IS A BRAND NEW IN THE BOX SQUARE D DEFINITE PURPOSE MAGNETIC STARTER W/ OVERLOAD/HEATER. A magnetic starter is an electromagnetically operated switch which provides a safe method for starting an electric motor with a large load. Magnetic starters also provide under-voltage and overload protection and an automatic cutoff in the event of a power failure. HP: 10 Model # 8911DPSG52V09 WHAT IS A MAGNETIC STARTER & WHAT PURPOSE DOES IT SERVE?? A motor starter is for the purpose of protecting a motor that has no thermal overload protection in the motor itself. The starter consists of two devices, a contactor that completes the circuit to the motor and an overload relay that monitors the current the motor is drawing . The thermal type magnetic starter uses a device installed on the overload relay called a "heater" this is a bi-metal element that each leg of the motor goes through and comes in different ratings based on the full load amperage of the motor. While the motor is running the current flows through the heater, if the current draw of the motor exceeds the rating of the heater, the heater element heats up and causes the relay to "trip" which interrupts the contactor coil circuit and de-energizes the contactor. |