Nautel XR6, Troubleshooting Manual, Page: 30 / 291

XR6/XR3 Troubleshooting Manual Responding to alarms
Page 1-10 Issue 3.0 2009-07-15
Figure 1.2: XR6/XR3 Exciter Panel Assembly (NAE93 – A2)
2. Connect a digital multimeter (set to measure dc) between TB1-2 (
EXT INTLK
) of the remote
interface PWB and ground.
3. If 24 V is present on TB1-2, the external interlock circuit is intact and the probable cause of
the alarm is a defective monitoring circuit. Suspect the remote interface PWB or the control/
display PWB.
4. If 24 V is not present on TB1-2, measure the voltage between TB1-17 (
EXT +24V OUT
) of
remote interface PWB and ground, then between TB1-1 (
EXT INTLK
) and ground.
5. If 24 V is present on TB1-1 and TB1-17, the external interlock circuit is open (normally
caused by an open interlock switch).
Low B+ voltage
A
Low B+ Voltage
alarm is triggered when the B+ voltage falls below its factory-set threshold of
about 250 V (B+ = 315 V), 150 V (B+ = 190 V) or 91 V (B+ = 115 V) for 3-phase XR6; 177 V
(B+ = 220 V) or 91 V (B+ = 115 V) for 3-phase XR3; 250 V (B+ = 315 V), 155 V (B+ = 196 V),
91 V (B+ = 115 V) or 55 V (B+ = 69 V) for 1-phase XR6; or 175 V (B+ = 220 V), 155 V (B+ =
196 V), 91 V (B+ = 115 V) or 55 V (B+ = 69 V) for 1-phase XR3.
Besides being noted on the status screen and the
System Diagram
, this alarm causes a shutback, the
Softstart relays to open, and the fan and RF drive power supplies to turn off.
Remote
Interface
PWB
A2A6
A2A2 A2A1 A2A3
A2A4
A2A5
RF Synthesizer
PWB ‘B’
RF Synthesizer
PWB ‘A’
Interphase
PDM Driver
PWB ‘A’
Interphase
PDM Driver
PWB ‘B’
A2
Exciter
Interface
PWB
Remote Interface PWB