Overvoltage Relay; Checking Overvoltage Relay - Piper SENECA II Service Manual

PIPER SENECA II SERVICE MANUAL
Breaking this circuit disables the balancing circuits in both regulators.
c. Operate the "RIGHT" engine at approximately 1750 RPM and at a load of 15 to 30 amperes for
approximately 5 minutes for warm-up; then turn the "LEFT" alternator switch "OFF" and set the RIGHT
voltage regulator (to the left while facing aft) to 14.0-volts; then replace its plug button. This regulator
should require no further adjustment.
d. Connect a voltmeter between the two "FIELD" terminals, turn the LEFT alternator switch ON,
and adjust for minimum voltage; however, the voltage should not exceed 8-volts. This adjustment will be
"touchy," and polarity will reverse as zero is passed.
e.
Reconnect the PAR wire and note that the voltage as observed in Step 4 drops to less than .5-volt
and becomes steady. Check that bus voltage is still 14.0-volts; then shutdown engine.
f. Replace the plug in the regulator; remove all voltmeter leads and test equipment and install the
closeout panel in the baggage compartment.
11-24. OVERVOLTAGE RELAY.
11-25. CHECKING OVERVOLT AGE RELAY. The relay may be tested with the use of a good quality,
accurate voltmeter, with a scale of at least 20-volts and a suitable power supply, with an output of at least
20-volts, or sufficient batteries with a voltage divider to regulate voltage. The test equipment may be
connected by the following procedure:
a. B+ is connected to "Bat" of the overvoltage control.
b. B- is connected to the frame of the overvoltage control.
c. Be sure both connections are secure and connected to a clean bright surface.
d. Connect the positive lead of the voltmeter to the "Bat" terminal of the overvoltage control.
e. Connect the negative lead of the voltmeter to the frame of the overvoltage control.
f. The overvoltage control is set to operate between 16.5-volts to 17 .5-volts. By adjusting the
voltage an audible "click" may be heard when the relay operates.
g. If the overvoltage control does not operate between 16.5 and 17 .5-volts, it must be replaced.
Re~sued: 10/11/79
ELECTRICAL SYSTEM
2G14