What does the Seal-in Voltage relate to in a contactor coil?

The concept of Seal-in Voltage is critical when discussing the operation of a contactor coil. It refers specifically to the minimum voltage needed to maintain the engagement of the coil's armature after it has been activated. When the coil is powered up to a certain level, it generates a magnetic field strong enough to close the contactor and connect the circuit. Once the contacts close, the voltage required to keep the armature engaged can be lower than the initial energizing voltage, and this is known as the Seal-in Voltage.

Understanding Seal-in Voltage is vital for ensuring that the contactor remains engaged without requiring the full voltage originally applied. If the voltage drops below this threshold while the circuit is in operation, the coil may disengage, leading to loss of connectivity and possibly causing the machinery or circuitry to stop functioning. Thus, the Seal-in Voltage plays an essential role in the efficiency and reliability of electrical systems that utilize contactors.