Chevrolet DB90 Series, Руководство по обслуживанию

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S ec. 6Y -135
A. C. GENERATING SYSTEM (NON-INTEGRAL TYPE)
adjuster one notch counterclockw ise, then check
fo r an improved battery condition after a s e r v ic e
p eriod of reasonable length.
c. If the regulator cannot be adjusted to a
value within the sp ecified range, repair or rep lace
the regulator.
REGULATOR CIRCUIT TEST
(WITH 9 000590 REGULATOR)
IMPORTANT: O bserve the follow ing te st pro­
ced u res in order liste d . Im proper connections and
p roced u res may instantly damage the equipment.
NOTE: T est adapter (J-21600) may be u sed to
fa cilita te making te s t connections at the regulator.
FIELD RELAY CHECK
1. Connect a voltm eter to te st adapter as
shown in View A, figure 17.
2. Make su re ignition or control sw itch is in
"OFF” p osition.
3. O bserve voltm eter reading.
a. If voltm eter in d icates battery voltage, the
fie ld relay contacts are stuck c lo sed and the relay
m ust be replaced.
b. If voltm eter reads zero , p roceed to Step 4.
4. Connect a jum per lead between field relay
No. 1 term in al and No. 3 term in al. Slide te st prods
into connector body to make connections.
5. Turn ignition or control sw itch on.
a. If voltm eter reads battery voltage, p roceed
to "Field C ircuit Check" la ter in th is sectio n .
b. If v o ltm eter reads zero , check for e x c e s s ­
ive r e sista n c e or an open circu it between battery
and "BAT” term inal on generator, between battery
and No. 3 relay term in al, betw een No. 1 term inal
on relay and "POS” term inal on regulator, or b e ­
tw een "NEG" term in al on regulator and ground.
FIELD CIRCUIT CHECK
1. Connect a v o ltm eter to te st adapter (J-
21600) a s shown in View B , figure 17.
2. Turn ignition or control sw itch on.
3. If voltm eter read s 1 or 2 volts l e s s than
battery voltage, p roceed to "Generator Output
Check."
4 . If voltm eter reads zero , the regulator is
d efective and m ust be repaired or replaced.
NOTE: Since the regulator defect may have
been caused by a d efective generator field , check
the fie ld a s follow s b efore in stallin g a new regu ­
la to r.
a. Turn ignition or control sw itch off and d is ­
connect negative battery cable from battery. D is ­
connect te st adapter from the regulator.
b. Connect an am m eter to the adapter a s shown
in V iew C, figu re 17.
c . If ohm m eter reads high, th ere is an open,
o r e x c e s s iv e r e sista n c e in the field winding or in
w iring betw een regulator "FLD" term in al and
generator "FI" term inal.
d. If ohm m eter reads low , the winding is
shorted or grounded.
NOTE: Since the reading is taken through the
adapter, lea d s, b ru sh es, and slip rin gs, the ohm­
m eter reading on a good field winding w ill be
sligh tly higher than the sp e cified value. This is
b ecau se the sp ecifie d value is for an ohm m eter
reading directly a c r o s s the slip rings.
e. D isconnect ohm m eter and connect negative
battery cable to the battery.
5. If the voltm eter read s battery voltage, the
regulator is shorted and m ust be replaced or r e ­
p aired, or the generator fie ld winding is open or
grounded.
a. To check the field winding, follow p roced ­
u r e s liste d in a. through e. under Step 4 above.
b. To check the regulator, connect a v o lt­
m eter a s shown in V iew A, figu re 17, then start
engine and operate at m oderate speed. If voltage
i s uncontrolled and in c r e a se s with sp eed to values
above the sp ecified settin g range, r ep la ce or r e ­
p air the regulator.
GENERATOR OUTPUT CHECK
NOTE: Check generator for sp ecified output
a s follow s:
1. Connect an am m eter in circu it at output
"BAT" term in al on the gen erator.
2. Connect a voltm eter to the adapter as shown
in View A, figu re 17.
3. Turn on ignition or control sw itch.
4. Operate generator at sp ec ified speed and
check for rated output a s lis te d in "Specifications"
at end of this sectio n . Load battery with a carbon
p ile or veh ic le a c c e s s o r ie s (if needed) to obtain
rated output. If generator does not produce rated
output, rep air or rep lace the generator.
NOTE: A fter gen erator is in stalled on the
v eh icle, connect an am m eter in circu it at output
"BAT" term in al of the gen erator and check for
e x c e s s iv e r e sista n c e a s follow s:
EXCESSIVE RESISTANCE CHECK
NOTE: E x c e ssiv e r e sista n c e in the sen sin g
c ir cu it co n sistin g of lead s from No. 1 and No. 3
te rm in a ls on the fie ld relay and lea d s from "NEG"
o r "POS” term in als on the regulator can cau se an
overch arged battery. If trouble is not battery o v e r ­
charge, r e fe r to "Voltage Setting Adjustment" la ter
in this sectio n , oth erw ise p roceed a s follow s:
1. Connect a voltm eter a s shown in View D,
P a rt 1 and P art 2 in figu re 17.
2. R em ove jumper lead from field relay unit,
then connect a jumper lead from battery to No. 2
term in al on the rela y . D iscon n ect lead after 60
secon d s to prevent overheating.
CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT