When you’re under tight time constraints, quickly locate faults with the DC Scout—with as little as 2 mA of current—in nuclear plants, power generation plants, oil refineries, chemical plants, ships, and fire alarm systems. The D.C. Scout is used for locating resistive or non-resistive current paths from DC Battery Distribution System to building ground without de-energizing components or loads in the system.
- -No disconnecting leads to isolate grounds in complex DC circuits
- -Follow pulses to ground with clamp-on detector probe
- -Troubleshoot critical control systems quickly and accurately
- -Locate grounds with as little as 2 mA of current
Instrument consists of two basic parts:
- Pulser Unit: Used to pulsate current through the DC battery – DC Scout – building ground loop
- Pulse Detector Unit: Used to detect pulses generated by the Pulser Unit in the DC battery – DC Scout – building ground loop
The D.C. Scout repeatedly opens and closes (pulses) the closed circuit, established when D.C. Scout is connected. Current flows from the (+) battery pole, through the wire shorted to building ground, through the D.C. Scout building ground lead, then back through the D.C. Scout +/- battery lead to the negative battery post.
Note that the ground detection system battery is the source of the current flow, not the Scout.
The D.C. Scout Detector Unit can then detect and show these pulses on the Detector Unit Meter where the Pulse Detector Current Transformer Probe is clipped over a wire in the current path.
This systematic approach of noting where pulses have been detected, then moving down the wire to where pulses are not detected, pinpoints the ground fault location.
Always wear proper Personal Protection Equipment when working on and around energized circuits
Work involves energized circuits
Inspect all energized equipment for proper installation and functions before initializing work
DC Scout Limitations:
D.C. Scout Pulser Unit should be connected in parallel with grounded circuit (positive or negative ground); it will have full battery voltage across it for a solid ground or partial voltage across it for a resistive ground.
Pulse amplitude will be set for a minimum of 5 mA to a maximum of 200 mA DC.
D.C. Scout Pulser Unit has two in-line fuses to ensure protection of D.C. Scout and system it is analyzing. If more sensitive protection is desired, a lower amperage quick-blow fuse may be substituted; this would limit output capacity of D.C. Scout.
Under no circumstances should a fuse rating of more than 250 mA be installed in BATT FUSE or GRND FUSE fuseholders.
With both Switches A and B on, there is no current limiting resistors in circuit and it is possible to quickly blow D.C. Scout Pulser Units BATT FUSE or GRND FUSE.
Download: DC Scout Tutorial/Operating Instructions
At times there can be difficulty discerning between the desired pulses on the Detector Meter and random pulses, or “noise.”
For those pulses/spikes, which are circulating from (-) to (+) in the circuit, clamp the D.C. Scout’s Pulse Detector Probe around both (-) and (+) wires at the same time. The circulating pulses will cancel out and you should see only the D.C. Scout’s pulse, which is not circulating on both the (+) and (-) wires.
For those pulses/spikes that are radiating down a wire and are not circulating, move down the wire, if possible, to get away from noisy systems such as choppers, and inverters. It may be necessary to decreases the sensitivity of the Pulse Detector and increase the amplitude of the D.C. Scout’s pulse in order to override the remaining interference.
The “Pulse Frequency Adjust” control on the D.C. Scout Pulser Unit can be adjusted so that the frequency of the Scout’s pulses stand out from the existing noise.
Description: Housed inside instrument case, mounts pulse meter and user adjustable controls
Operating Voltage: 125 VAC, 250 mA front panel fuse protected
Relay Output: 250 VDC, 250 mA front panel fuse protected
Relay Timing: 2 to 8 cycles per second, user adjustable
Relay Indicator Lamp: 14 VDC, bayonet style
Pulse Amplitude Meter: 0-300 mA DC, pivot and jewel style, with user selectable 30 or 300 mA range
Description: Super-sensitive pulse amplifier, housed in poly carbonate shell with neck strap
Operating Voltage: 9 VDC, transistor battery powered
Meter: Taut band, zero-center
Detector/Probe Sensitivity: 2 mA min. pulse amplitude (for detectable meter movement; slightly more for optional probe)
Sensitivity/Balance Controls: Adjustment controls mounted on rear panel
Battery Test: Rear panel push button with meter indication
Dimensions & Weight: 3 3/8″ x 3″ x 5 1/8 ” – 1lb
Current Transformer Detector Probes:
Standard Probe: 2″ circular jaws, 14oz.
Optional Probe: .5″ x 4″ opening, 5 oz.
DC Scout Configurations:
- The D.C. Scout can also be configured for 220 VAC (P/N: HJA-2525-220)
- Nuclear plants
- Power generation plants
- Oil refineries
- Chemical plants
- and fire alarm systems
Locating A.C. Grounds
The D.C. Scout can be used to locate grounds on A.C. system up to 480 volts, provided the following conditions are met.
The A.C. circuit must be totally de-energized and disconnected from its source. This means all phase leads and the neutral lead, if used.
A 130 Volt D.C power supply must be available that is capable of supplying 200 mA of current. This D.C. voltage must be isolated from ground. This means that the (+) and (-) leads each read zero (0) volts to ground when energized.