Testing Regulators - Piper SENECA II Service Manual

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+
l/2W
2,200 OHM
11-22. TESTING REGULATOR.
PIPER SENECA II SERVICE MANUAL
L PRESS - TO - TEST
I
NORMALLY OPEN
DC
I
AMMETER
Figure 11-11. Testing Regulator
CARBON
PILE
BATTERY
a. The procedure for testing the regulator whether on the airplane or on the test bench remains the
same. Connect the test meters and regulator wiring as shown in Figure 11-11.
b. All circuit connections should be clean and tight. This includes the test instrument connections
which must not come loose or open the charging circuit at any time while the system is operating.
c. The voltmeter will not indicate the true regulator setting until the regulator has been operating in
the charging system or on the test bench for at least five minutes, at a charge rate of from IO to 15
amperes.
d. With the connections made as shown in Figure l l-11, start the engine and adjust its speed to
approximately 920 to 1250
RPM
to obtain 3,000 to 4,000 alternator
RPM.
Turn on accessories as needed
to establish a 10 to 15 ampere load value. Note that the battery charge current is indicated by the ammeter.
Therefore, the current value may change downward at the beginning of a test run. This will be especially
true if the battery was used for engine starting.
e. After one minute operating time, check the regulator operating voltage as indicated by the
voltmeter. Refer to Alternator Service Test Specifications, Paragraph 11-15 for the correct operating
voltage. The operating voltage is shown for the ambient temperature in which the regulator is operating.
f. If the voltmeter reading indicates that the operating voltage is not within limits, lift the plastic
plug from top of regulator and adjust the voltage to the desired value. Replace the plug after adjustment.
Before condemning the regulator, recheck the alternator and the battery, making sure that they are in good
condition. Recheck all circuit connections and all wiring for unwanted resistance (voltage drop test).
Recheck the voltmeter for accuracy and repeat the entire operating test.
Reissued: 10/11/79
2G12
ELECTRICAL SYSTEM