Model PD Short Locator


Model PD Short Locator


Tinker & Rasor Model PD Short Locator
Tinker & Rasor Ranger IV Receiver Tinker & Rasor PD-C Oscillator


Components of PD Short Locator

Letters refer to picture above.

  • A. Mark IV Receiver with batteries (1 spare)
  • B. PD-B Oscillator
  • C. Head set with cushions
  • D. Battery cables (set): black for -, red for +
  • E. 30′ black ground cable
  • F. 6′ red oscillator-to-pipe cable
  • G. Carrying case
  • X. Instruction manual (not shown)

Optional Accessories for Locating Holidays

Letters refer to picture above.

  • H. Shoe cleats (set of 4)
  • I. Terminal board (single connect)
  • J. Terminal Board (double connect)
  • K. 30′ connecting cable
  • L. Cleat Cables (set of 4)

PD Short Locator

Tinker & Rasor’s Pearson-Type Detector, Model PD, is an all transistor instrument. Its light weight, low battery drain, and rugged construction are features that make it a very productive tool. Without uncovering the pipeline under test the PD Detector can be used to:

  • locate discontinuities in the coating of buried pipelines
  • locate electrical contacts on the pipelines
  • locate the pipelines themselves.

A Pearson-type detector can be used successfully only if a pipeline has been carefully backfilled and the soil is compact around it. There also must be some moisture content in the surrounding soil. Cleats are worn by two inspectors walking in tandem. The cleats are terminated by cable connections to a receiver worn on the belt of one inspector. They enable him to accurately find holidays or large discontinuities in pipe coatings. The search coil can locate the pipe or any shorts.

Tinker & Rasor’s Model PD and the Null Method have been recognized as being the fastest method to accurately locate points of electrical contact and insulating joints on coated underground piping systems. The Tinker & Rasor Model PD is unaffected by parallel lines, depths, 60 Hz, or ground cover. The survey can often be conducted from a moving vehicle traveling over the pipe. In brief, the Null Method follows the flow of impressed audio frequency current in a coated pipe and determines where it leaves the pipe. This method is quite practical, because competent field personnel can interpret findings quickly and accurately. The Model PD is also an excellent device for pinpointing defects in coatings on buried pipelines. This unit is accurate for locating breaks in cables such as anode leads in impressed current cathodic protection systems.

Mark IV Receiver

The New Mark IV Receiver employs a high gain, integrated circuit amplifier that is signal-to-noise optimized by three 750 Hz active filter elements. Modern circuit design insures maximum circuit stability even when operated at ambient temperature extremes. The filter attenuates AC and DC interference. The search coil is contained within the receiver and has low impedance of 2,000 ohms. Although earphones are furnished for operator’s optional use, the loudspeaker offers advantages related to safety, convenience, and comfort. Built-in battery test and signal intensity meter of modern full-face design for ease of observation. Multi-directional depth level gauge for accurate (within 1 inch) depth determination.

PD-B Oscillator

The oscillator provided with the set has been designed to use the latest developments in this type of instrumentation. A signal of 750 Hz is generated by using a power transistor switching circuit. This arrangement eliminates troublesome vibrators, buzzers or other moving part elements. The transistor oscillator converts low voltage (12 V) DC to stable audio frequency AC directly. By a highly efficient method, the input current to the oscillator is only 1.7 amperes for a full output of fifteen watts, a conversion efficiency of better than 80%. In order that a maximum of energy can be transferred from the oscillator to the pipe, the output of the oscillator is provided with taps so that voltages of 2.5, 5, 7.5, 15, 50 and 100 Volts are available to match the load. An interrupter is provided to make the signal more easily recognized.