Tektronix TCP300A, User Manual

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Application Notes
Application Notes
This section describes some of the typical measurement applications of the
TCPA300 and TCPA400 Current Probe Ampli
fi ers:
Automobile Charging Systems
Inductance Measurements
Continuity Test of Multiple-Conductor Cable
Measuring Inductor Turns Count
Power Measurement and Analysis Software Applications
Automobile Charging Systems
Most automotive charging systems are three-phase alternators with a diode
recti
fi er 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. (See Figure 20 on page 36.)
A TCP303 Current Probe was used for this high-current, low-voltage application.
The TCP303 is degaussed and clamped around the positive battery lead from the
alternator. (See Figure 19.) The probe arrow is pointed away from the alternator
and toward the battery side of the circuit, to re
fl ect conventional current. The
automobile is started and the lights are turned on to add a signi
fi cant load to the
circuit.
Table 5: 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
TEKPROBE interface cable) 10 A/Div (200 mV/Div)
Zero-Current Reference Center graticule line
Time Base 200 ms/division
TCPA300/400 Ampli fi ers and TCP300A/400 Series Current Probes User Manual 35