Quickly Trouble Shoot An Intermittent Solenoid Valve Coil

When Troubleshooting an Intermittent Solenoid Valve Coil sometimes the following problem occurs, and when it does it can shut a manufacturing production line down for hours. Whenever I test a solenoid valve with the Magprobe and the LED light does not come on it’s an electrical problem. So I measure the voltage applied to the coil to see if it’s present. Next, I turn the power off and make a continuity measurement of the coil to see if it’s OK. But how is this possible if the coils resistance checked okay and the voltage was present? You should have current flow through the coil and you don’t. Why is that?

Because:

The LED should light up when voltage is applied to the solenoid valves coil because current flowing through the coil is what generates a magnetic field. The magnetic field in turn energizes the MagProbe and the light comes on.
Now you know the coils windings must be opening when the voltage is applied. This Intermittent problem was caused by a tiny opening in the coils winding that occurred when voltage was applied. When current flowed through this tiny spot on the coil it caused heat and resulted in expansion of the tiny contact which caused it to Open and Interrupt the current in the coil. When this happens a magnetic field Will Not be Produced and the Magprobe LED will not light. No Schematic is needed to make this test.

When the voltage is removed, the coil cools down and results in wire movement causing the tiny separation to reconnect. Once it reconnects you can now measure continuity with the Ohm Meter.
Intermittent Problem Solved.

Call Bob Bartol at (208) 866-7895 Email inventorbobis@gmail.com

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