Alternator Self Excitation Test (-5 & -5Ls Only) - Planet ES-10024B-1 Maintenance Manual

Aircraft Alternator
Maintenance Manual
5.4 Alternator Self Excitation Test (-5 & -5LS only)
A. Self-excitation ability is derived from residual magnetism in the rotor pole pieces, which provides the minimum
generated voltage necessary to power the ACU and begin producing power. (This provision only on the ES-
10024B-5 or -5LS alternator.)
B. In order to verify the minimum voltage necessary for self excitation, run the alternator at 5000 RPM with no
load (B+) or field connections. Use a digital multimeter (DMM) on the DC Volts scale, to measure the voltage
between B+ and case ground. The minimum voltage specified is 2.0 VDC.
C. If minimum self-excitation voltage is not above the specified voltage above, attempt to restore self-excitation
using the following procedure.
(1) A voltage regulated DC power supply with the current limit set to 3.5 amp, can be used to "polarize" the
rotor by briefly applying 28VDC (nominal).
(2) Connect the positive lead of the power supply to the F1 terminal.
(3) Connect the negative lead to F2 terminal or the alternator case if the F2 terminal is not present.
(4) Ensure the power supply adjustment is set to zero.
(5) Turn on the power supply and slowly increase the supply voltage adjustment to 28 VDC.
(6) Wait 5 to 10 seconds and slowly decrease the supply voltage adjustment to zero.
D. The minimum open circuit voltage at 5000 RPM should again be checked. Any unit that fails to polarize
per the steps above should be removed from service. Self-excitation applies to ES-10024B-5 or -5LS only.
(Do not put an ES-10024B-5 or -5LS into service which does not meet the minimum self-excitation voltage
criterion.)
ES1031
Rev. A: 11 Aug. 2021
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24-30-01
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