When measuring the resistance of a contactor coil, a reading of zero ohms indicates?

A reading of zero ohms when measuring the resistance of a contactor coil indicates a shorted coil. This is because a properly functioning coil should exhibit some resistance, typically measured in ohms, which allows for a certain amount of current to flow when voltage is applied.

If the resistance measures zero ohms, it means that there is a direct electrical connection with no resistance, indicative of a short circuit. In this scenario, the winding of the coil is likely compromised, allowing current to bypass the coil's intended path. This condition can lead to improper operation of the contactor or potentially damage the circuit, as the coil may draw excessive current.

A functioning coil normally shows a resistance value that is above zero, reflecting its operational characteristics and ensuring it can effectively create the magnetic field required to operate. Therefore, a reading of zero ohms is a clear sign of failure in the coil's insulation or windings, confirming the coil is shorted.