Fig.2 The overall system of automatic measurement and
examination for DC motor
2.2 Hardware system
Fig. 3 shows a hardware system of developed
platform. Proper sensor components are used to sense
the related parameters such as transient current, steady
current and temperature for tested motor. The sensed
signals are sent to computer through DAQ (data
acquisition) card [1-4]. Then the measured data is
analyzed and displayed on the monitor by LabVIEW.
The signal acquisition circuit framework is shown in
Fig. 3.
Fig.3 The hardware system of platform
(a)Relay Switch
Fig. 4 shows the connected circuit between tested
motor and DAQ card. A relay switch is controlled by
LabVIEW through DAQ card. When a 5V from DAQ
card is sent to relay switch, tested motor is connected to
dc source to begin automatic measurement.
Fig.4 The connected circuit between tested motor and
DAQ card
(b)Hall Sensor
Fig. 5 shows Hall sensor circuit. It is very
convenient for non-contacted current measurement. The
Hall sensor, made of semiconductor materials, is
applied to measure current by magnetic Hall Effect.
Hall sensor is widely used to examine magnetic field
and its variation. It has the advantages of slight
volume, small power, light weight, long life, high
bandwidth with strong structure, and so on. The Hall
sensor specification characteristics are shown in Table
1.
Fig.5 the Hall sensor circuit
Table.1 The Hall sensor specification characteristics
Fig. 6 shows an OP amplifier circuit for Hall sensor.
The sensing data from Hall sensor is properly amplified
by OP amplifier, and is sent to DAQ card.
Pg 490