Silicon Controlled Rectifier (Scr) Module - Kohler 8.5RES Service Manual

4.9 Silicon Controlled Rectifier
(SCR) Module
The silicon controlled rectifier (SCR) module works with
the ADC 2100 to regulate the output voltage. The
ADC 2100 monitors generator output voltage and
adjusts the excitation current to the rotor through the
SCR module. The SCR module location is shown in
Figure 4-1.
The SCR module is powered through stator leads 55
and 66 connected to SCR terminals AC1 and AC2.
Leads G connected to terminals G1 and G2 provide the
controller signal. Leads FP and FN connected to the
positive (+) and negative (--) SCR terminals provide
excitation current to the rotor. See Figure 4-16 and the
wiring diagrams in Section 7.
The SCR module is protected by a 20-amp fuse (F1) in
lead 55 in the wiring harness. Check the fuse and
replace it, if blown.
In the case of output voltage problems, check the
controller configuration and settings. Then test the SCR
module using the following procedure.
SCR Module Test Procedure
Required equipment:
D
Ohmmeter
D
12-volt test lamp (or voltmeter)
D
12-volt DC power source
D
100--500 ohm resistor
D
Jumper
1. Set the ohmmeter to the RX1 scale.
2. Connect the ohmmeter from (+) to (--) on the SCR
module. You should read high resistance in one
direction and low resistance in the other (reverse
the leads).
AC1
AC2
Figure 4-16 Silicon Controlled Rectifier (SCR)
Module
TP-6196 5/04
G1 --
G2 +
GM28483
3. Connect the ohmmeter from AC1 to (+) on the SCR
module. You should read high resistance in both
directions.
4. Connect the ohmmeter from AC1 to (--) on the SCR
module. You should read high resistance in one
direction and low resistance in the other.
5. Repeat steps 3 and 4 for AC2.
6. Connect the ohmmeter from G1 to (+) on the SCR
module. You should read low resistance in both
directions.
7. Repeat step 6 for G2.
resistance in both directions.
8. See Figure 4-17. Connect the negative (--) lead
from the DC power source to the positive (+)
terminal on the SCR module.
Note: The SCR module may be damaged if the
power supply is connected incorrectly. Be
sure to connect the negative lead from the
battery to the positive terminal on the SCR
module.
1
(--)
4
G1
(+)
G2
1. 12VDC power source
2. 12 VDC test lamp
3. SCR module
4. Jumper
5. 100--500 ohm resister
Figure 4-17 SCR Test
You should read low
2
(+)
5
3
AC1
AC2
(--)
tp6196
Section 4 Controller 35