Tektronix TCPA300 SERIES, Instruction Manual

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TCPA300/400 Amplifiers and TCP300/400 Series Current Probes Instruction Manual
3- 11
Application Notes
This section describes some of the typical measurement applications of the
TCPA300 and TCPA400 Current Probe Amplifiers:
H
Automobile Charging Systems
H
Inductance Measurements
H
Continuity Test of Multiple-Conductor Cable
H
Measuring Inductor Turns Count
H
Power Measurement and Analysis Software Applications
Automobile Charging Systems
Most automotive charging systems are three-phase alternators with a diode
rectifier network. A meter averages current from all three phases, and cannot
detect a single-phase diode problem. Observing the charge current waveform can
quickly reveal if one diode is shorted or open.
The diagram in Figure 3--7 shows the equipment setup. Refer to Table 3--2 for
the test equipment setup. A TCP303 Current Probe was used for this high-cur-
rent, low-voltage application. The TCP303 is degaussed and clamped around the
positive battery lead from the alternator. The probe arrow is pointed away from
the alternator and toward the battery side of the circuit, to reflect conventional
current. The automobile is started and the lights are turned on to add a significant
load to the circuit.
Table 3- 2: Automobile charging systems test setup
Instrument Control Setting
TCPA300 COUPLING DC
RANGE 50 A/V
Oscilloscope Coupling DC
Amps/Division
(Volts/Division if not using TEK-
PROBE interface cable) 10 A/Div
(200 mV/Div)
Zero-Current Reference Center graticule line
Time Base 200 s/division