B&K Precision 302 - Manual - Manual (Page 9)

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FRONT PANEL LAYOUT PRINCIPLE OF HOW IT WORK
The tester has two separate circuits:
The first circuit is the 3 Phase presence indicator, which is shown by
the neon lamps and the second circuit is the three phase sequence
indicator by LEDs.
A low battery, with a Power On indicator circuitry is also present.
3 Phase Presence Indication circuit:
This circuit uses neon lamps to indicate if a phase is present.
These neon lamps are connected in series with a limiting resistor.
Neon lamps will lights up when the voltage accross any two phases
is more than 100Vac.
3 Phase sequence indicator circuit:
This circuit has an analog and a digital part. The analog signals are
amplified (so that motor rotation with very low signals can be
performed), then compared to a set of references. These results are
digitally compared to give the results on the indicating LEDs.
Switch-ON and low Battery detector:
At switch ON, the battery voltage is measured and compared. If the
battery voltage is below the threshold, the LED will not light up, thus
replacing the battery indication.
TEST
BAT
OK
L3 L2 L1
L2 L1 L3
L1 L2 L3
CAT.III 600V
R
/
U S
/
V T
/
W
Connect L1 from tester to U of motor.
Connect L2 from tester to V of motor.
Connect L3 from tester to W of motor.
Turn the motor shaft by at least half a turn
clockwise (towards the right)
Depress the TEST button,
L1L2L3 = clockwise motor rotation.
L2L1L3 = anti-clockwise motor rotation.
MOTOR ROTATION TESTER
PHASE PRESENCE INDICATOR
PHASE ROTATION TESTER
Connect L1, L2 and L3 to their respective
Phase. Their corresponding Lamp will
light up when power (>120Vac) is present.
Depress the TEST button, The Led L1L2L3
will indicate clockwise phase rotation.
If anti-clockwise phase rotation is
present, the Led L2L1L3 will light up.
MOTOR ROTATION DETERMINED WHILE
USER FACING (looking at) MOTOR SHAFT
302