Published: November 2002
While meat-and-potatoes testers like clamp-ons and multimeters can do the job for many electricians most of the time, there are specialty testers that may benefit users exponentially some of the time. Here are selected products from the latest crop of niche instruments that offer electricians expanded capabilities while going through the paces in a wide variety of spaces.
Infrared thermography uses infrared technology to record and analyze radiated energy from an object's surface. For example, infrared imaging equipment relies on an infrared sensor, such as a short-wave camera sensitive to electromagnetic radiation microns (a tiny fraction of an inch) above an object's surface, to detect overheated conditions in various types of facility equipment. When used in preventative/predictive maintenance, by monitoring any overheated conditions, or hot spots, it is possible to reduce the occurrence of system failures and unscheduled outages. By scanning electrical equipment, personnel can detect loose or corroded connections and splices, overloaded conductors and circuits, overheating lighting ballasts, unbalanced loads, and other conditions that could then be addressed for correction, possibly reducing downtime or eliminating more costly repairs.
The Hioki 3460 2D Thermo HiTester is a lightweight, handheld 64-element thermopile array sensor, integrated camera and a display that provides instantaneous two-dimensional images and measurement of radiated energy. The instrument, sporting a 3.8-inch color liquid crystal screen, features three ways to display images: visual, which is a picture of the object without radiated energy information, and mosaic image and box display, both of which are 64-point and show radiated energy. The first view helps in pinpointing hot spots in relation to the other two views. Temperature is calculated from the radiated energy. The color of each mosaic tile of each border corresponds to the colors of an on-screen temperature bar gauge, facilitating the ability to locate hot spots. When a temperature alarm is set up in advance, measurement values flash at locations with abnormal temperatures. The unit has a compact flash card slot for recording and storing measurements.
A handy device for preventative maintenance tasks and other applications, the Fluke 61 infrared (noncontact) thermometer is suitable for almost instant measuring of surface temperatures of rotating, hard-to-reach, electrically live or dangerously hot targets. The single-button unit, which features ergonomic design, has a bright laser beam that helps target objects and a backlight that illuminates the display screen in the dark. The instrument's 8:1 optical resolution is suitable for a wide range of applications. A shock-absorbing holster provides field ruggedness. The automatic sleep mode extends battery life. Alkaline batteries can last for 4,000 typical measurements.
Electricians who need to check the operating speed of electrical equipment, for purposes of determining energy efficiency or other cost-effective parameters, can often use handheld tachometers to quickly and successfully measure equipment rotational speed (revolutions per minute of shafts) or linear speed (feet per minute of belts). Photo tachometers, which provide rotational measurement, typically use an infrared-type sensing system that enables operation from a limited distance, eliminating the possibility of any contact slippage and providing a safety zone during measurement. Contact tachometers support both types of measurement, using appropriate contact accessories such as tips and wheels. Combination models are available.
The Megger (formerly AVO International) 359987 digital combination hand tachometer is a lightweight, compact photoelectric tachometer with an adapter for mechanical contact. The instrument features microprocessor-controlled circuitry and a direct-reading LED coupled with a specialized infrared-type sensing system. Housed in a shockproof plastic body, the unit is insensitive to fluorescent light and electromagnetic fields and features five indicating digits and an auto-ranging, low-demand seven-segment liquid crystal display. The contact adapter slips over the photo-beam housing to permit contact measurements of linear speeds, and a self-test allows at-a-glance indicator verification of fully functioning electronics. The tester, with its memory recall, automatic switch-off for battery preservation, low-battery and over/under indications, reads directly in rpm and feet or meters per minute. The unit comes in a case with accessories.
The AEMC infrared tachometer Model CA27 is a handheld instrument that measures up to 100,000 rpm using infrared measurement. A combination digital/analog bar graph LCD displays the measurement clearly and accurately. Other features include auto or manual range selection, smoothing, minimum/maximum recording and hold functions, alarm, and count and print functions. Three mechanical adapters, part of the accessory kit, allow for direct connection and measurement to rotating shafts and other devices. High and low alarm levels are programmable as well as the display multiplier coefficient "K" (scale factor). RS-232 communication is standard for printer or computer interfacing. The Model CA27 is supplied in a carrying case with 15 reflector strips, 9V alkaline battery and a user manual.
Short finder and circuit tracer
When troubleshooting sophisticated job-site lighting panels, security systems and other systems, electricians sometimes run into faulty circuit boards and need to test for shorts. While short finders have long been used at test benches, they are also handy field tools.
The Meterman SF-10 short finder enables electricians to truncate the tedious process of finding electrical shorts in complex printed circuit boards. Its unique stainless-steel brush probe design eliminates the need to check each test point, so users can sweep over multiple points to instantaneously find the approximate location of continuity. The built-in probe tip can then be used to confirm the exact location of the short. Opposite usage confirms continuity absence within a circuit. The unit is also useful with multiconductor cables, mass termination systems, backplanes, connectors and IC sockets. A low-test voltage feature protects sensitive circuitry and eliminates false continuity indications.
Greenlee's microprocessor-based circuit seeker (Model 2011) is a circuit-tracing system that tracks concealed wiring, locates junction boxes and finds breakers for live or dead circuits, with no need for power interruption. The transmitter automatically indicates open, live or shorted line mode. Other features include the ability to find circuits in nonmetallic conduit, find breaks in wires and shorts to ground, and locate and identify blown fuses. The tracer receiver has an automatic shutoff to conserve batteries and the case-cover-mounted operating information adds convenience. The kit includes the transmitter, receiver and accessories in a rugged carrying case. Accessories include an adapter lead, AC blades, extension leads, an earphone/tube, two 9V batteries and an instruction video.
Some testers combine capabilities that might otherwise require an electrician to use two separate instruments. For example, when electricians are working on large motors, they often use clamp meters to check current and phase-rotation testers to determine correct motor rotation. However, the same functions are available in one specialty tester.
For example, Extech model 380974 1000A AC clamp meter and phase rotation tester, with jaws opening to 1.6 inches, measures AAC current to 1,000A and AC voltage to 600V with a +/- 1.2 basic ACV accuracy. The unit also measures resistance, capacitance, and frequency, and includes diode and continuity testing. Featuring a 3 3/4 digit (3,999 count) LCD, the tester sports data hold, peak hold, and a four-segment bar graph. The unit provides three-phase sequence testing with LCD status indication. Clockwise or counterclockwise wiring configuration, indicated by an arrow on the LCD, ensure that three-phase motor connections are correct. The tester comes with three test leads, a 9V battery and case.
Ideal Industries Model 61-704 is a versatile, ergonomic clamp-style tester that enables electricians to perform procedures that previously required four separate tools, resulting in economy, a less-cluttered tool bag and enhanced on-the-job safety due to the tester meeting CAT III standards. This troubleshooting tool has a 200A clamp/multimeter with true RMS, capacitance and backlight, noncontact voltage and harmonics testers, and AC voltage tester with shaker. The clamp/multimeter feature allows electricians to easily and accurately measure AC amperage, AC/DC voltage and resistance/continuity. The meter's tapered jaw permits access to cables inside tight spaces, and its slim profile makes for easy use and storage.
Installation and maintenance of power cables, switchgear and voltage tap changers require the cable joints and switch contacts to be of the lowest possible resistance, to avoid the joint or contact from becoming excessively hot. Joints or contacts that reach too high a temperature are apt to fail. Therefore, routine preventive maintenance that includes periodic resistance measurements helps ensure proper performance.
The Cropico D07 digital micro-ohmmeter is suitable for resistance measurement of switch contacts, electrical connectors, crimped and cable joints, PCB track, earth bonding, small transformer windings, heating elements, fuse testing and other applications where low-resistance measurement is required. The battery-operated unit is contained in a sealed ABS plastic case, with a lid and carrying handle. The instrument has a 0.8-inch LED 6,000 count display with automatic decimal point and polarity indication. A front-panel socket provides a serial RS232 output for connection to a PC or external printer. A second socket will connect to an external start switch.
When performing electrical work that requires knowing what is under the surface, surprises are seldom welcome. Digging at a facility where the subsurface is a web of cable, lines and pipe, the more an electrician knows what's below, the better off everyone is. While maps and records of underground networks are theoretically maintained, they are often out-of-date or incomplete, resulting in uncertain locating results. Wire tracers save electricians effort, eliminating exploratory digging to locate live and dead lines.
Amprobe AT-3000 Underground Hawk buried wire and pipes locator locates underground energized and de-energized wires, cables and pipes via three different test modes. Suitable for pinpointing shorts, ground faults and open wires, as well as buried wires and pipes, the unit can detect flowing current and reradiated radio frequency transmission from a buried line. It can also induce a signal into the line from a supplied accessory and then trace the buried item's location. The instrument, which has an audible loudspeaker and a LCD to indicate ongoing test parameters, is weatherproof and impact resistant.
3M Company's Telecom Access Division Dynatel M Series Locating and Marking System Model 2250, in conjunction with a 3M 1400 Series EMS-iD ball marker with custom memory chip, can respond to locator search signals by providing detailed facility data about the marked location. The results improve efficiency when locating underground features and can eliminate uncertainty regarding the exact location of the buried facility or feature. Markers are located via a utility-specific radio frequency signal that corresponds to the American Public Works Association (APWA) standards. The markers' memory can be programmed with specific information, such as a unique identification code, name of the underground component owner, component function (splice, drop, etc.), name of the contractor who placed it and other information. The identification code, typically, is referenced in an electronic database record and indicated on maps. Because they respond to specific locator search signals, the ID markers can, in congested areas, simplify clarification of what each wire is for and who is responsible for it.
Illuminance meters measure intensity, which is helpful in detecting overlighting or underlighting, and can be productive when verifying estimates or validating equipment nameplate data.
Yokogawa 510 02 Digital Illuminance Meter is a compact portable unit that measures a wide range from low to high illuminance. Switchable from lux to footcandles, the instrument, which is compatible with the JIS C 1609-1993 standard, is suited for oblique incident light and visible-region relative spectral responsivity. The unit supports recorder, digital and comparator outputs. Features include timer hold, ripple measurement, configurable color correction coefficients, light-source luminosity measurement, and four- and five-point average computation. Ripple measurement essentially blocks out sunlight, enabling measurement of the intensity of illumination indoors during the day. The timer hold allows the user to put the device down on a surface so the user's shadow or any reflection from clothing does not affect the measuring intensity of illumination.
The Gardner Bender GVT-92 solenoid voltage tester tests AC/DC voltage from 120 to 600V and DC polarity. Providing dual indication, the unit, which sports a high-impact case for rugged service, features both a lighted neon bulb and solenoid vibration to indicate voltage. Retractable spring-loaded probe guards protect metal tips and slide out of the way during tester use. Built-in slots in the unit's housing hold probes for one-hand testing. Lead storage in the housing affords convenient carrying in a pocket or a pouch. EC
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