Garmin G1000 Nxi System Maintenance Manual page 128

2. Touch negative lead of power supply to each of the test points listed while performing
Step 3. At each required point, configure the power supply to produce 1 amp before
measuring voltage. (Use an ammeter to ensure current is within minimum of 1 amp
±100 milliamp at each point). Do not allow the reference current to exceed 1.5 amps for
safety.
3. With the current set to 1A, the voltage reading will be the value of the bonding
resistance. Set the voltmeter to measure millivolts and null the reading. Measure the
voltage from airframe ground (step 1) to each required test points and record the
voltage. (Perform Step 2 at each required point and ensure that minimum of 1 amp
±100 milliamp is present when measuring the voltage.)
TIP: When a 1A current is used all the millivolt readings are the same as mΩ, and
required no further calculation of bond resistance. If 1 amp reference current cannot
be maintained and is higher divide the measured voltage by current to get the
resistance value. Alternatively, calculate the percentage increase in current and then
reduce the measured voltage reading by the same percentage. Example: If the
measured current is 1.2 amps, (20% high from the desired 1 amp current) and the
measured voltage is 3.0 mV, then the value recorded will be 3 mV reduced by 20%
which is 2.5 mV which is the same as 2.5 mΩ.
Phase 3 Electrical Bonding Procedure
Using one of the two measurement methods in Section 4.5.2 record the bonding measurement
for the following equipment. Some equipment in the list is optional and may not be installed.
Ensure that the PFD1 unit, PFD2 unit, MFD unit, and GMC 710 test points, no more than 30 mΩ
is present. Ensure that at other unit test points, no more than 5 mΩ is present.
• Top metal case of PFD 1: __________ mΩ
• PFD1 Cooling fan metal base: __________ mΩ
• Top metal case of PFD 2: __________ mΩ
• PFD2 Cooling fan metal base: __________ mΩ
• Top metal case of MFD: __________ mΩ
• MFD Cooling fan metal base: __________ mΩ
• Top metal case of GMA 1347D #1: __________ mΩ
• Top metal case of GMA 1347D #2: __________ mΩ
• Top metal case of GMC 710: __________ mΩ
• GEA 71 #1 body: __________ mΩ
• GEA 71 #2 body: __________ mΩ
• GDC 7400 #1 body (if installed): __________ mΩ
• GDC 7400 #2 body (if installed): __________ mΩ
• OAT 1 Probe base nut (inside fuselage): __________ mΩ
• OAT 2 Probe base nut (inside fuselage): __________ mΩ
• GDL 69A body: __________ mΩ
• Engine Signal Conditioner #1 near mounting holes of case: __________ mΩ
G1000 NXi System Maintenance Manual
King Air 300 Series
190-00716-N1
Pilot Compartment
Page 115
Revision 1