CAV control box issues and Fuses....

[rmgill]

Originally Posted by Richard Farrant

Ryan,

If you go to the workshop manual it explains the tests to be carried out, one like Lynn says, is to motor it over, a good basic test. Could be a dirty commutator, or sticking/worn brushes, or presence of oil or grease. As for the fuse, don't think it is lead, should be a thin aluminium, easiest thing is to source some fuse wire of 50 amps rating.

I'm thinking that there's a problem with an open lead on the back side. Though, when we swap the fan belts out for a slightly smaller size, we'll motor the generator tomorrow.

I've tried cleaning the voltage and current bobbin contacts. They appear good however.

So some more data here and more correct....

Field at the CAV box shows .2-.5 volts or there abouts.

The P lead shows ~1.8 volts for the green "not charging" indicator lamp.

The D+ lead shows 2 volts.

The Voltage and Current Bobbins are both closed and do not stutter. The Field cutout bobbin is open and does not close on it's own.

If I engage the cutout bobbin, I get battery line voltage on the generator and of course it's acting as a motor, apparently.

If I engage the cutout bobbin while the engine is off, the generator of course can't spin and the bobbin locks closed and then it releases when the fuse blows.

I'll take the unit out tomorrow so I can examine it on a bench more clearly. It would seem that there's no voltage on the current/voltage bobbins.

Lynn, it very well could be running up past 20 volts I just didn't want to see if I could let the smoke out by letting the voltage climb. Needless to say the generator seems to function if it gets enough field current. I did try a lower voltage from the P connection and got a lower rate of voltage climb.

RE the fuse,
I've managed to make a stand-in fuse out of .005 thick brass of the same shape and size. That should carry a bit less current and act reasonably well. I'll find some aluminum of the right thickness and carry out some better tests.