BRUEL & KJAER 4912 Instruction Manual page 6

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Portable
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Type 4,912
Fig.3. Control panel of Type 4912
is exceeded, the display flashes to
indicate out-of-range . When it is
used as a stroboscope synchronized
Frequency Ranges:
Flash rate: 0 to 130 Hz (with external
triggering)
Internal generator: 5 to 1 25 Hz
Display: 0 Hz to 1500 Hz and Or / min to
90000 r/ min . Display flashes if upper li-
mit is exceeded
External trigger: 0 to 20000 Hz
Tachometer Display:
Type: 4-digit liquid crystal display, 7-seg-
ment numerals 12 mm (0,5 in) high
Configuration: Display reads Hz to near -
est 0, 1 or 1 Hz, and r/ min to nearest 1
or 10 r / min
Accuracy: ± 1 part per thousand,
± 0, 1 Hz or± 1 r / min in lower ranges
± 1 Hz or± 10 r / min in higher ranges
Light Source:
Type: Xenon white-light discharge tube
Average Light output: Greater than
2500 lux up to 250 mm ( 10 in) range
and greater than 1000 lux up to
500 mm (20 in) range, for flash rates
above 25 Hz (1500 r / min)
with the machinery or system being
studied, the flash rate range is O to
130 Hz.
Specifications 491 2
Flash duration: 5 µs approx
.
Beam diameter: Typically 60 mm (2.4 in)
at 500 mm range
External Trigger:
Connector type: 3 -pole coaxial BNC, ac-
cepting plug JP 0315
Trigger voltage: ± 100 mV, adjustable
(rising to ± 200 mV at 20000 Hz), on in-
nermost pole of socket, referred to shield
Supply for trigger source:
+
5 V DC to
+
7 V DC (internal batteries), or
+
6 V DC
to
+
10 V DC (ext . power source), on pole
no . 2 (ring) of socket , referred to shield
(can be used to power Photoelectric
Probe MM 0012)
Power Input:
Connector type: standard 7-pin DIN
socket accepting plug JP 0703
Charging: + 6 to + 1 5 V DC, 0 to
600 mA, 7 hours at max . rate; or from
battery charger ZG 0113, 10 hours
External power:
+ 6 to + 15 V DC, max .
7 W to 1 5 W respectively with strobo-
Fig.4. Battery Charger ZG 0113
In this operating mode the exter-
nal trigger will lock to triggering fre-
quencies up to 20000 Hz, and if
they are greater than 1 30 Hz the
flash rate will be a · submultiple of
the triggering frequency.
The 491 2 is a completely self-
contained unit, powered from re-
chargeable batteries built into its
carrying handle . The integration of
the light source, power supply and
generator into a hand-held instru-
ment weighing only 1 ,3 kg makes
the Portable Stroboscope ideal for
studies of moving machinery in
cramped, confined spaces and rem-
ote locations where transportability
is essential. It may be recharged
from the mains using battery
charger ZG 0113 (Fig.4, supplied),
or recharged and operated from the
mains using Mains Power Supply
Type 2808 and control cable AO
0035 (both obtainable to order).
scope operation, 1 W to 5,5 W respec-
tively with tacho . only
Battery condition: moving-coil indicator
Weight:
1 ,3 kg (2 ,8 lb approx .)
Dimensions:
Height: 265 mm (10.4 in)
Width: 135 mm (5,3 in)
Depth: 93 mm (3,7 in)
Accessories Included:
Battery charger
3-pole BNC plug
7-pin DIN plug
2 spare fuses
Accessories Available:
Photoelectric tachometer
probe
Magnetic probe
Mains Power Supply
Control cable
Tripod bush adaptor
ZG 0113
JP 0315
JP 0703
VF 0010
MM 0012
MM 0002
Type 2808
AO 0035
UA 0588