Ripple Regulator Circuit; Adjustments - Marconi LORAIN RHM800E50 Manual

4.10 This rectifier contains a circuit which permits
selective overvoltage shutdown when two or more recti-
fiers are operated in parallel. The circuit allows opera-
tion of the overvoltage shutdown circuit only in the
4.11 This rectiiier is equipped with a ripple regulator
circuit. located on cinutt card Al 1, which continuously
monitors the ripple current through the rectifier DC out-
put filter capackors. In the event of a high ripple current
condition caused by the loss of an AC input phase, the
ripple regulator circuit senses the high ripple through
the capacitors and provides a signal to the rectifier regu-
current. This permits the rsctiiier to continue operating
at a reduced capacity until such tkne as the phase loss
is corrected. External alarms are also actttated refer to
Paragraph 3.14 for details.
4.12 If rectifier operation off battery is required, a
capacitor assembly, Part No. 425101400, must be
installed on circuit card A7 to stabilbe rectifier output
voltage. See Figure 4-1.
I
4.13 The rectifier is equipped with cooling fans and
temperature sensors mounted on heatsink assemblies
at the bottom of the cabinet. The cooling fans circulate
air across the heatsinks to cool power semiconductors
while the temperature sensors monitor heatsink tem-
perature. lf air flow ceases or il heatsink temperature
I
reaches +85'C (+18X=). output current of the ractffllr
is reduced to approximately 88% of the full load rating,
and an external rectifier fail alarm is activated, if con-
I
nected. In addition. if a cooling fan has failed, a red FAN
FAILURE indicator will illuminate. When the tempera-
ture decreases or fans have been repaired, the rectifier
returns to full load capability and the external rsctffiir
I
fail alarm is canceled.
I
4.14 Table 4-l lists the rating and types for all the
fuses used in the rectkier. Fuses should be replaced
I
access to all fuses except F5 and F6, open the meter
and control panels. Fuses F5 and F6 are accessible
I
I
after removal of the lower panel at the front of the recti-
fier.
Table 4-l. Fuse Types and Sizes
C. wcuft Cards
4.15 Any of the circuit cards listed in Table 4-2 can
easily be replaced as individual assemblies if the need
arises.
Circuit Card
Al-A6 (433401600)
A7 (486508700)
A8 (486562200)
A9 (433852700)
Al6 (433800209)
Table 4-2. Replaceable Circuit Cards

5. ADJUSTMENTS

5.1
accessible on the control and indicator panel at Regula-
tor and Alarm Circuk A7 and Ripple Regulator Circuit
All. These potentiometers are factory adjusted and
readjustment is not normally required.
Section 4387
Description
Regulator 8 Alarm Card
Power Supply Card
Alarm Interface Assy
I Riiple Reaulator Card
LED Alarm Card
HVSD Resart Circuit
Page 9
I
I