Piper Comanche PA-24 Service Manual page 673

PiPeR COMANOIE SERVICE MANUAL
9-21. R ... let ••.
Th. re",lat .. abo,", iJI
FiCUre
9-3 CODaI.1I 01 a cut""t relay. a volta .. re",-
lator. IIId a c ..... at replater llllit. Th. cutout reloy close. the ....
rtlor-!~ttery
circuit .bea
the .... r.t .. volta .. is sufficient to ch .... tbe batt.ry. aad it
0 . . . . .
the circuit wh.a the .. aer-
.tor .1 .... dowa . . . tops. Th. volt ... r .. utor llllit is a volt .... limitilla device th. prev ... t.
the
ay .... volt ... Ir ... nceediJIa •• pacified .. u i _ aad thus protecta the bett.ry cd other
volt ...... Dsitiv. equipmeat. The current replato. Ullit i •• c ..... Dt-limitiJIl d.vlc. that limits the
lnerator output so as
flat
to exceed itl rated maXimum..
9-22. C.t .. t
Rei.,. .
•. Th. cutout r.l.y (Fia"'" 9-3)
~
.. two .iJldina ••• I.ri ••• iJldina of • fe. tuml
cI
h.avy
wire and a shuat .indiA, of many t ..... of fiA • • ire (Ihown iA d .. heeI liDH). Th. IhUDt wiAdiJI,
i. coanacted acrou the .. aerator
10
that leaer.or volta .. il impre .. ed _
it • • U ti ..... Th.
lerin wmdina i.
COftD.ected in series with the eberlin. circuit 10 til. aU
._ratar output
puses
throuah it. The relay core cd .indiAll are ...... bled iJlto a fr ..... A flat Iteel arm."", is .t-
tached to the fr ....
by •
flexible hiA .. 10 that it ia C8fttered jlllt ab .... the :"111
cI
tha core. Th •
• rm.ture contact poUlt. are located jUlt above tha .t.tionary cootact poUlt: 'b.n the ,e .. r.tor
is Dot opar.iA,. the .....
ture
coatact poiAlS are h.1d . . . y from the ltatioowy poiJIts
by
the teD-
lian of. fl.t IpriDg riveted on the lid. of the .... atur ••
b. Wh.n the ,etWr.ter volt ... buildl up • v.l .. ,reat enoaah to cha .... the b.ttery. the ... g-
Deti ... iJlduced by the rel.y wiAdiJlp is .uffici.Dt to pull the ..... twe toward the co ..
'0
that the
cootact poiDts cl .... This c ... pl.t.1 the circuit betwHa th . . . aerator and bettery. Th. c ...... at
.hich flow. from the .. nerator to the bett.ry pas.e. through the seti_ wiAdUI, iA • direction to
add to the _anelil .. holdiAl the ...... t_ dawn and the contact poiAts closed.
c. Wh.a the .. aerator 110 . . dawD or ItOpa • .:arreDt baaiD. to flow fr ... the bettery to the
.eneratOl.
d. This reverse
flow of
current through the seri .. windinl caues
I
reversal of the series
wiAding ".In.tic field. Th. ".&netic fi.ld
cI
the shunt wiJIdiA, does aot reverae. Therefore. in-
stead of helpiJI, each other. the two windings now .. agnetic.lly oppooe so that the .. Iultaut ... ,-
netic fi.ld
bee .....
iAsufficie"t to hold the ..... ture down. Th. nat SPM' pulls the ..... ture
.... y fr ... the core so that the poiAts s.perat.: this
open.
the circuit be_n the ,.Der.tor .Dd
battery .
9-23. Volt.,e .... I.t ...
L Th. volt ... r.",latar (Fi"". 9-3) h .. two _diJI,s ...... bled on a linale core •• abunt
windin, cOIISistinl
<:t ..
any tum. of fin • • ire (Ih""" in d .. heeI liDeI) which is shunted aerol.
the ",D.rator. and . . . riel .indiJIl of • few tum.
cI
relatively heavy .,ire wbich il connected in
seri •• with the pa.raux fi.ld circuit wh.n the r .. ulllor coatact points are closed.
b. The .,indiA,1 and core are ...... bled into. fram •. A flat Iteel ..... ture i •• ttached to
the fr .... by • flexible hin .. so th.t it is
just above the .nd of tb. core. Th. ar ... ture contams 8
contact point wbich is just bell.ath a statioaay
CCIl,act
point. When the voliale rel'll.tar is not
operotiaa. the t.naion of a spiral Ipring holdl the ar .. eture a.oy fro .. the care
10
th. the poiJIts
are iA contact and the leneratar fi.ld circuit i. co .. pleted to arOllDd throuah them.
c. When the .. nerator volt.,e r.acb.1 the v.lue for which the
yolt., . . .
au!ator is adjusted.
the ... gn.tic fi.ld produced by the two windinas (.bUDt and •• riel) ov.rcQll\ •• the ...... ture sprine
tenl10ft
and pulls
the armat\lfe dawn
10
that the contact poiDta .. parate. This inserts resistance
iAto the ,.nerator fi.1d c1rcuit
10
tbat tb. generator fi.ld curreat and volt ... are reduced. Reduc·
tion of the pn.r.tor volt ... reduce. the .... ".IlC fi.ld of the re,uI.tor Ihunt wiJldine. Alia.
3 A21
ELECTRICAL SYSTEM
ISSUED: 8/18/72