| Physical size:
The complete SPITFIRE transmitter is housed in a compact, rugged steel
carrying case manufactured to our requirements. The sectionalized ground
probes, which fit conveniently in a tray within the case, eliminates the
need for space to store large, cumbersome "A" frame probe assemblies.
Ease of use: Using the SPITFIRE to locate a faulted cable from a customers meter socket, there is no need to completely disconnect the customers service from the transformer. After the operator identifies the faulted cable, even though the faulted cable is energized, the SPITFIRE can be connected to pinpoint the fault. To obtain 120 volts AC to operate the SPITFIRE, an adapter assembly is provided to connect between the unfaulted cable and the neutral.
Simple operating procedure: There is no need to know exactly where the cable is buried, just the general direction from the house to the vault or transformer, when using the SPITFIRE to locate cable faults. The color-coded probes and impulse detector meter simplify interpretation, simply move in the direction of the color indicated by the meter deflection. Reversal of the signal and cross-locating at a right angle finally results in an "X" directly over the fault.
High sensitivity: There is nothing more discouraging than trying to detect a weak earth gradient signal provided by a battery powered impulse generator. A weak signal caused by dry soil or sand is almost impossible to identify. Since the SPITFIRE is operated from a 120 volt power source, the impulse generator consistently provides a nominal 960 volt peak pulse after pulse. The sensitive detector system will detect a signal whether you're in wet or dry soil, sand, concrete or asphault, resulting in fast identification of the fault location. You will not excavate for a fault and not find the cable.
Fast, economical service: The SPITFIRE is disigned and built to withstand the normal use generally associated with linemens' tasks, with minimal maintenance. However, from time to time, maintenance may be required. Having an electric utility background, we know the importance of fast repair service. Because the SPITFIRE is well constructed, you get an instrument which is economical to purchase and maintain, providing years of reliable service.
With an eagerness to introduce new instruments and to improve the design and performance of existing instruments, TIMCO INSTRUMENTS does not plan to abandon the SPITFIRE secondary fault locating system. The voltage gradient method employed by the SPITFIRE is the most accurate method to pinpoint a buried cable fault, and we've been doing it for over 25 years. And we will continue to improve the performance of the SPITFIRE.
The SPITFIRE secondary cable fault locator employs a voltage gradient measurement technique to accurately pinpoint secondary cable failures. The output pulse of the transmitter, up to 30 amperes peak, developes a voltage gradient in the earth between the cable fault and the seperately driven ground return. Because of the unique design of the output circut, the SPITFIRE can be connected directly to the faulted cable at the customer's meter socket without ever disconnecting the secondary service cable from the padmounted transformer. To ensure an optimum output pulse, the SPITFIRE operates on a 120 volt AC source. An adapter is included as a standard accessory to provide access to 120 volts at customer's meter sockets and secondary terminals of transformers.
Two indicator lamps on the SPITFIRE transmitter inform the operator that the SPITFIRE is connected to a 120 volt source and is operational. The next step in locating the fault is to determine which cable or cables are faulted. With the ouput leads properly connected, turn on the SPITFIRE transmitter and place the "black" stainless steel ground probe near the driven ground attached to the black output lead. Place the "red" probe about twelve to twenty-four inches away, in the direction of the cable route. If the meter deflects when the transmitter discharges, there is a fault in that particular cable and the operator would proceed to locate the fault.
The detector contains a differential amplifier which produces a meter deflection indicating the relative position of the ground probes to the cable fault. Since the detector senses the voltage gradient in the earth, the wider the probes are spaced apart, the greater the input signal. To quickly locate cable faults, hold the detector probes so that they are along a line between the customer's meter and the distribution transformer. Continue probing along this line until the meter deflection reverses. Back up until a null (no meter deflection) is located. Draw a line on the ground between the two probes. Turn the probes at a right angle to the this line and locate a null in this direction. Draw a second line on the ground between the probes again. Turn the probes at a right angle to the this line and locate a null in this direction. Draw a third line on the ground between the probes again. Below the intersection of the second and third lines is the fault's location.