When a contactor's coil is energized, how much resistance should be measured between terminal LI and T1?

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Multiple Choice

When a contactor's coil is energized, how much resistance should be measured between terminal LI and T1?

When the coil is energized, the contact controlled by that coil closes. That creates a conductive path directly between the two terminals it connects, so the resistance looks like a very small short rather than a large value. In other words, LI and T1 become essentially the same node through the closed contact, so the measured resistance is near zero ohms. If the coil weren’t energized, that path would be open and the resistance would appear infinite. The coil’s own winding does have resistance, but across LI and T1 you’re testing the closed contact’s path, which is why the reading is effectively zero.

When the coil is energized, the contact controlled by that coil closes. That creates a conductive path directly between the two terminals it connects, so the resistance looks like a very small short rather than a large value. In other words, LI and T1 become essentially the same node through the closed contact, so the measured resistance is near zero ohms. If the coil weren’t energized, that path would be open and the resistance would appear infinite. The coil’s own winding does have resistance, but across LI and T1 you’re testing the closed contact’s path, which is why the reading is effectively zero.

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