3
1. INTRODUCTION
The Magna-Trak 100
®
magnetic locator is a fl ux-gate type of magnetometer which incorporates a unique patented
technology that enables the factory to balance the magnetic sensing coils to a fi nite condition. This patented
method of magnetic balancing is advanced in the state of the technology.
The Magna-Trak 100 implements “peak response” over ferromagnetic objects by yielding an increasing audio
signal as the object is approached and passed over.
This instrument is the product of many years of experience and service provided by CST to the industry.
2. THEORY OF OPERATION
The Magna-Trak 100 locator fi nds ferromagnetic objects by sensing the magnetic fi eld radiated by the object.
The locator contains two sensor coil assemblies that are precisely spaced and electronically balanced to achieve
a near magnetically-balanced operating condition. In a uniform magnetic fi eld, such as the earth’s fi eld, the two
sensor coils maintain a magnetically-balanced status, because both of the coils experience the same magnetic
lines of force. However, when a ferromagnetic object is approached, the fi eld strength and angle of the magnetic
lines upon each sensor is different. This difference, although minute, is enough to offset the critical balance and
produce an audible indicating signal (
Fig. 1
).
When no ferromagnetic objects are present, the speaker emits a steady low frequency tone. As the object is
approached, the audio frequency increases until the center of the object is directly beneath the locator’s lower tip
sensor. The frequency peaks and then decreases as the object is passed. The peak indicates the exact location of
the object.
Nonferrous objects do not affect the locator. Objects made of brass, aluminum, copper, etc. are ignored.
Fig. 1
Sensor coils unbalanced by magnetic fi eld of iron stake.
