🚀 go-pugleaf

Could someone tell me how an aircraft fuel capacitance system works. What
does the compensator do. I think that the compenstator  corrects or offsets
for changes in fuel temperature?

I work on Learjet 60 type aircraft which uses a DC fuel capacitance system.
The system consist of 4 probes in parallel per wing , one fuselage tank
probe and one electronic indicator . The system is powered by 28vdc, no ac
used.
Only one of the probes(left wing inboard) has the compensator probe.   The
back of the indicator has three bnc connectors. The left and right wing bnc
connect to four paralleled probes mentioned above. The fuselage only has one
probe.  The indicator displays fuel in pounds for the left and right wings,
fuselage  and sum total for all three tanks.

We have a tester that connects to each of the bnc connectors on the back of
the indicator . You must first disconnect  one of three bnc connectors and
connect the tester to check for left/ right wing and fuselage tank
capacitance. So in effect the indicator reads the change in capacitance as
fuel is added(refueled)  or consumed during flight.

Questions:
1. Does the indicator produce some sort of sign wave, because I thought only
AC worked with capacitance?
2. If you remove one of the four paralleled probes while checking for
capacitance will capacitance value show higher or lower?
3. The  tester has connection points called low Z and high Z. I know that Z
indicates  AC impedance which is kind of like resistance in a DC circuit.
Why is there a low and high Z??
4.  How does the compenstator   work?
5.  Do the 4 paralleled probes in each wing display an average?

My knowledge is very limited in how capacitance systems work. I did take a
simple AC/DC course a few years back.
In addition to posting, could you please email me at
Tommy.D.Wippert@worldnet.att.net