Overvoltage Control - Piper PA-24 Comanche Service Manual

PIPER COMANCHE SERVICE MANUAL
.TTIItY
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fiGURE 9·27r. APPLICATION OF
OYERVOLTAGE CONTROL
fiGURI "'71,. TESTING OVERVOLTAGE
CONTROL
•
c. Caution Notes:
1.
Use only with inaulated (ul\lfoWKIed) field altematOts.
2. Regulator bale must have a lood Irouad connection.
3.
Do not COMect .round pOWl!lr to aircraft UIltil volta ..
~aulator
"I"
terminal has been
disconnected from electrical system.
4. Do not (even momentarily) connect the two volta.. repl.tor terminals tOlether.
5. Do not connect battery into Systelll with oolarity N"rsed.
6. Do not force the volta.. adjust_nt screw.
';. This is a sealed unit and not repairable. Replace with a • • unit.
9-615. O"e",olto,. Contr.l.
9-61t. Pur,o,. Ancl O,e,otlon.
a. The avervolt,go control is uaed to protect electrical circuits and electronic equipment
from excessive voltace in the eqnt of a cbarlilll Circuit malfwlction.
b. The overvolta.e control consists of a mechanical relay and a solid state triaerinl de..
vice. The solid state tricc_rinc device activates the mechanical relay. when the voltage reaches
a preset value. thereby opening tha relay contacts and discoftlWCtinlthe fieldcireuit oft
he
alternatot.
c. The relay contacts will remain open until the alternator switch
is
turned off. Ficure 9--27r
ill\lStratn the overvolt_ce control connected in a typical Pr.tolite insulated field altarnator.
•
9-61u. Tast Proceclure. Connect the relay as shown in Fieure 9-275. U.a a
l~hm
potenti..
ometer of 1S-watt ratine, or more. to adj\lu the voltaga. The voltmeter is used to read the voltace
until the relay ,ope
!'IS •
at which time the voltmeter toedina will drop to zero. See tabulation for
voltage reading. Test ficures are at 7S deC1Hs Fabrenheit. These Wlits are not adjustable. Re-
place the overvoltage control if it does not test to specifications.
Relay contacts open between 16.2 and 16.&-volts. Use 18 or 24..volts ,to test.
ELECTRICAL SYSTEM
ISSUED: 8/1sn2
3
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