Main Field/Exciter Armature Resistance Test - MULTIQUIP DCA Series Service And Troubleshooting Manual

MAIN FIELD/EXCITER ARMATURE RESISTANCE TEST

MAIN FIELD RESISTANCE TEST
NOTICE
Before performing the resistance test, the two black
lead wires (Figure 36) must be disconnected from
the rotating rectifier.
The main field (Figure 36) consists of two black lead
wires with no wire designation. These two wire leads are
connected to the DC positive and DC negative terminals
on the rotating rectifier in conjunction with the surge
protector.
MAIN
FIELD
A
SELECTION
W
V
U
A
WIRE
COLOR W
DC
V
BLACK (2)
U
POS.
DC
NO WIRE
NEG.
DESIG.
UNSOLDER
WIRE LEADS
FROM ROTATING
RECTIFIER
Figure 36. Main Field Resistance Test
Using a multimeter (Figure 36), check the resistance across
each black wire as referenced in Table 6, column B. Be
sure to place the selection dial on the multimeter to the
Ω position. If the reading indicates an open circuit the
component may have to be replaced or repaired.
PAGE 36 — GENERATOR SERVICE AND TROUBLESHOOTING MANUAL — REV. #0 (08/29/23)
EXAMPLE:
DCA-25SSIU4F = 4.0Ω
MULTIMETER
MULTIMETER
0 Auto 600
TURN
RANGE MIN MAX REL Hz %
HOLD/LIGHT
DIAL TO Ω
Hz
C F
POSITION
mV
uA
V
ROTATING
V
Hz
RECTIFIER
OFF
mAµA COM
10 A
MAX
EXCITER ARMATURE RESISTANCE TEST
NOTICE
Before performing the resistance test, the three yellow
lead wires (Figure 37) must be disconnected from the
rotating rectifier. If the reading indicates an open circuit
the component may have to be replaced or repaired.
The exciter armature (Figure 37) consists of three yellow
lead wires with no wire designation. These three wire leads
are connected to the U, V and W terminals on the rotating
rectifier.
Using a multimeter (Figure 37), check the resistance across
each pair of wires as referenced in Table 6, column C. Be
sure to place the selection dial on the multimeter to the
Ω position.
mA
A
TURN
SELECTION
DIAL TO Ω
POSITION
Figure 37. Exciter Armature Resistance Check
EXAMPLE:
DCA-25SSIU4F = 0.30Ω
MULTIMETER
EXCITER
STATOR
MULTIMETER
0 Auto 600
WIRE
COLOR
RANGE MIN MAX REL Hz %
HOLD/LIGHT
YELLOW (3)
Hz
C F
W
mV
uA
V
V mA
U
V
Hz
A
NO WIRE
OFF
DESIG.
mAµA COM
10 A
MAX
MEASURE
A UNSOLDER
WIRE LEADS
W
V
U
FROM ROTATING
RECTIFIER
A
W
ROTATING
V
RECTIFIER
U
W TO V
= 0.30Ω
W TO U
V TO U