22-02-2022, 09:11 PM
(This post was last modified: 22-02-2022, 09:15 PM by John Cornforth.)
Hi bob
I attach a diagram of the CF3 internals based on the best information I have. I suggest you check that the shunt coil is OK by using an ohmmeter with the wires to the cutout temporarily removed. The shunt coil is usually earthed by a short link from the E terminal to a nearby earth tag on the bulkhead.
The pull-in voltage is adjusted by very slightly bending a piece of bent metal that acts as a stop for the contact assembly in its open position
CF3 Cutout.jpg (Size: 39.13 KB / Downloads: 127)
Readings of 18 volts suggest that either the cutout isn't closing or you are using a modern electronic voltmeter which is being sent haywire by the voltage spikes present in all A7 systems. An old fashioned AVO or similar is a better bet.
I attach a diagram of the CF3 internals based on the best information I have. I suggest you check that the shunt coil is OK by using an ohmmeter with the wires to the cutout temporarily removed. The shunt coil is usually earthed by a short link from the E terminal to a nearby earth tag on the bulkhead.
The pull-in voltage is adjusted by very slightly bending a piece of bent metal that acts as a stop for the contact assembly in its open position
CF3 Cutout.jpg (Size: 39.13 KB / Downloads: 127)
Readings of 18 volts suggest that either the cutout isn't closing or you are using a modern electronic voltmeter which is being sent haywire by the voltage spikes present in all A7 systems. An old fashioned AVO or similar is a better bet.