Checking Voltage Regulator; Checking Overvoltage Relay - Piper 6X Maintenance Manual

3.

Checking Voltage Regulator

A. Use only a good quality, adjustable DC power source.
CAUTION: ALL TESTS MUST BE ACCOMPLISHED WITH THE REGULATOR OUT OF THE
CIRCUIT.
B. Use a quality, accurate voltmeter with at least a 35-volt scale.
CAUTION: AMBIENT TEMPERATURES SURROUNDING VOLTAGE REGULATOR MUST BE
BETWEEN 50° F AND 100° F.
C. Voltmeter connections (refer to Figure 23.)
Connect positive voltmeter lead to red wire (supply) at regulator harness connector or wire.
D. Light Bulb Connections (refer to Figure 23.)
(1) Connect one bulb lead to blue wire (field) at regulator harness connector or wire.
(2) Connect other bulb lead to regulator ground wire (black).
E. In the regulation check procedure, increase voltage to regulator and monitor both the voltmeter and
bulb.
F. As the regulation point of a properly functioning control unit is approached, the bulb will blink off and
on. At regulation, the bulb will be ON continuously.
G. If regulator does not regulate to 28 Volts, it is out of calibration, and must be replaced.
H. If regulator checks good, check airplane for:
(1) Poor or loose connections.
(2) Poor ground on regulator housing.
(3) Shorted alternator windings.
(4) A grounded wire.
I. After completing test, connect regulator into circuit
4. Checking Overvoltage Relay (See Figure 24.)
The Lamar regulator has an incorporated overvoltage relay. To check relay operation use the same test
connections as testing the regulator, except connect the bulb across the RED and BLUE wires. Test as
follows:
A. While monitoring both the voltmeter and the light bulb, increase voltage to circuit slowly to 32 volts.
B. After a slight delay, the bulb will light.
C. If overvoltage control fails to operate at 32 Vdc, it must be replaced.
PAGE 26 24-30-00
Jun 1/03
THE NEW PIPER AIRCRAFT, INC.
PA-32-301FT / 301XTC
MAINTENANCE MANUAL
2H2