GE Bently Nevada 86517 Operation Manual page 19

Notes for Figure 2.4
1 The accelerometer case is connected to the machine earth and the
differential signal output is isolated. The installer must ensure that the
accelerometer mounting structure has the same ground potential as barrier
ground. Total earth loop impedance should be less than 1 ohm. The
accelerometer case connects to the extension cable shield through the cable
connector for the hardline cable and to the inner shield for the softline connector.
3 The interface module case must be isolated. The interface module must be
installed in a housing which meets approval agency requirements for the
installation site.
Wiring Recommendations:
2 Accelerometer to interface: Use extension cable, Bently Nevada part
numbers 45358-07 and -09, or 83387-xxx, or equivalent.
4 Interface module to monitor, Power, Common, and Velocity signal wiring
recommendation: two twisted pairs of stranded 18 to 22 AWG wire with insulating
sheath and 100% shield coverage. Connect the -Velocity wire from the monitor to
barrier ground but not to the interface module. The shield connects to the CASE
SHIELD terminal at the interface module. The maximum length is 800 feet (244
metres) between the interface module and the barrier and 1000 feet (305 metres)
between the interface module and the monitor. Use Bently Nevada part number
02101200 or equivalent.
5 Interface module to monitor, acceleration signal wiring recommendation:
Single twisted pair, stranded 18 to 22 AWG with insulating sheath and 100%
shield coverage. Connect the -Accel wire from the monitor to barrier ground,
(connection is made inside the barrier), but not to the interface module. The shield
connects to the CASE SHIELD terminal at the interface module. The maximum
length is 800 feet (244 metres) between the interface module and the barrier and
1000 feet (305 metres) between the interface module and the monitor.
Shielding:
6 Shield connects to barrier ground.
7 Shield connects to barrier ground.
10 Shields float at monitor. -Velocity and -Accel must connect from
monitor to barrier ground.
Safety Barriers:
8 MTL 796(-) barrier is recommended for power and velocity signal. Power:
V =
max
-26 V, R = 300 ohms. Velocity: V
min
Section 3 - INSTALLATION
= -20 V, R = 390 ohms.
max min
15