Chevrolet 70 Series 1970, Service Manual

Page: 595 / 841

ENGINE ELECTRICAL 6Y-54
lig h ts, or if the m eter reading is low when con­
nected from any stator lea d to the fram e, the wind­
ings a r e grounded. If the lamp fa ils to light, or if
the m eter reading is high when su c c e ssiv e ly con­
nected betw een each p a ir of sta to r lea d s, the wind­
in gs a re open.
If the stator o r diodes check bad it w ill be n ec­
e s s a r y to rem ove and d isa ssem b le the alternator.
NOTE: A short circu it in the stator windings
is difficult to locate without laboratory te st equip­
ment due to the low r e sista n c e of the windings.
H ow ever, if a ll other e le c tr ic a l checks a re norm al
and the generator fa ils to supply rated output,
shorted stator windings a re indicated.
REGULATOR REPLACEMENT (Fig.
8
)
After disconnecting the th ree identically co lo r ­
ed regulator le a d s, the regulator may be replaced
by rem oving the attaching sc r e w s and disconnecting
the regulator lead from the h ea tsin k . When in sta ll­
ing the regulator, refer to figure 7 for proper lead
connections.
OITTPUT CHECK
A fter d isa ssem b ly and rep air, m agnetize the
rotor a s covered under "Magnetizing The Rotor"
p reviou sly in this sectio n , then recheck the g en er­
ator a s covered in "Troubleshooting Procedures"
e a r lie r in th is sectio n , by making connections as
shown in figu re
6
.
REM EM BER — The output terminal
is red, connect this terminal and ammeter
to battery positive post, and battery neg-
ative post to generator frame._______________
Torque the output term inal insulated bolt 100-
1 1 0
inch-pounds when attaching cable.
GENERATOR REPLACEMENT
Due to variation s in design and the equipment
u sed , the replacem ent p roced u res w ill vary a c ­
cordingly. The rem oval and in stallation in stru c­
tion s follow ing a re intended only a s a guide. Addi­
tional operations w ill be required on so m e v e h ic le s
to rem ove other equipment to gain a c c e s s to gen er­
ato r, drive b elt, an d /or b ra ck ets.
GENERATOR REMOVAL
1. D isconnect negative battery cable.
IMPORTANT: It is im portant that battery neg­
a tive term in al be disconnected, sin c e generator
w ill be damaged if w iring or term in a ls a re a c c i­
dentally sh orted or grounded w h ile being discon­
nected.
2. R em ove bolt from the e le c tr ic a lly insulated
output term in al, then rem ove the lea d . D isconnect
rela y term in al lead from generator.
3. L oosen adjusting arm clam p bolt and gen­
erator to mounting bracket pivot b olt. M ove gen er­
ator to lo o sen drive belt, then rem ove d rive b elt
from generator p u lley.
4. R em ove adjusting arm clam p bolt and mount­
ing bracket bolt, then rem ove the generator.
GENERATOR INSTALLATION
IMPORTANT: B e su re negative battery cable is
disconnected from battery. F ailu re to disconnect
the cable may resu lt in damage to gen erator.
NOTE: R efer to figure 1 for typ ical generator
in stallation .
1. P o sitio n generator in mounting bracket and
in sta ll mounting bracket pivot bolt and adjustm ent
arm clamp bolt with hardened s t e e l w ash ers as
shown in figu re 1. Tighten pivot bolt nut fir m ly .
2. P la c e drive belt over gen erator drive pulley
and adjust belt ten sion as explained under "Drive
B e lt T ension Adjustment" p rev io u sly . Tighten
mounting bracket pivot bolt and adjustm ent arm
clam p bolt to torque recom m ended in "Specifica­
tions" at end of th is sectio n .
3. P la ce output term in a ls on output term in al
bolt and in sta ll. Tighten the hex head bolt firm ly .
P r e s s relay term in al lead over relay term in al.
4. Connect negative battery cab le to battery,
then perform "Generator Output T est" d escrib ed
p reviou sly to determ ine if generator is operating
properly and regulator i s co r r e ctly adjusted.
5. Install p ro tectiv e sh ie ld o v er generator
d rive pulley.
OPTIONAL 105-AMP. LEECE-NEVILLE INTEGRAL TYPE GENERATING SYSTEM
NOTE: Information applicable to generator
d rive b elt ten sion adjustment rem ain s the sam e as
covered under "Standard 75-Am p D elco-R em y
Integral Type Alternating Current Generating S y s­
tem " p reviou sly.
GENERAL DESCRIPTION
T his generator, u sed a s optional equipment
on so m e v e h ic le s, is cooled by a sin g le fan attached
to a drive p u lley.
The generator c o n sists of two m ajor parts: A
sta to r and a rotor. The sta to r i s com posed of a
la r g e number of windings a ssem b led on the inside
of a lam inated core attached to the gen erator fram e.
Two b ru sh es carry current through slip rin gs to
c o ils which a r e wound con cen tric with the rotor
shaft.
CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL