T272 RADIODETECTION | Alldatasheet
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High Resistance Cable Fault Locator Features / key benefits l The T272 high resistance cable fault locator has been designed to meet the requirements of engineers in locating cable faults in the resistance range from zero to 200 megohms. Faults can be between two conductors, or between a conductor and its metallic sheath, concentric neutral or earth. l Easy to operate, the T272 features solid state circuitry and utilises a conventional Wheatstone Bridge circuit in which the two sections of the faulty conductor, one on each side of the fault, together with a good conductor if necessary, comprise the two external arms of the bridge. The other two arms of the bridge are contained within the instrument. l By employing a detection circuit of extremely high input resistance it is possible to locate high resistance faults without the loss of sensitivity associated with other types of low and high voltage bridges. A ten turn vernier balancing control is provided which indicates the fault position as a percentage of the total loop length. If both ends of the faulty conductor are not accessible at the test end then a good conductor of the same crosssectional area is required. If the good conductor is of a different size then a conversion factor may be used to calculate an equivalent loop length. Alternatively, a pair of conductors from an auxiliary cable may be used or, if the cable length is not too great, an overland lead can be run out to enable the bridge test to be carried out. l With this bridge arrangement, faults having resistances up to 200 megohms in dielectrics such as rubber and polyethylene can be located with an accuracy well within ± 0.5% of the loop length and typically 0.1%, although this may be limited by the nonuniformity of the conductor. l The T272 is contained within a fibreglass housing fitted with a carrying strap. All terminals, controls and null detector microammeter are mounted on the top panel. l Complementary to Bicotest TDRs for locating high insulation resistance faults.
instrument (internal): 9V battery, PP3 Alkaline Power supply for bridge network (external): A DC source with output voltage to suit the cable under test must be provided, eg. 12V lead acid battery for power cables, or a dry battery for smaller cable sizes and telephone cables. Weight (kg): 1.4kg Size (mm): 155 x 245 x 110mm Delivery includes: Main unit with shoulder strap, 1 x PP3 9V Battery, Operating Manual in zipped plastic wallet, Connecting leads. Warranty: One year 90/T272/ENG/02 Copyright © 2016 Radiodetection Ltd. All rights reserved. Radiodetection is a subsidiary of SPX Corporation. Radiodetection and Bicotest are trademarks of Radiodetection Ltd. Due to a policy of continued development, we reserve the right to alter or amend any published specification without notice. This document may not be copied, reproduced, transmitted, modified or used, in whole or in part, without the prior written consent of Radiodetection Ltd. Radiodetection (USA) 28 Tower Road, Raymond, Maine 04071, USA Tel: +1 (207) 655 8525 Toll Free: +1 (877) 247 3797 rd.sales.us@spx.com Radiodetection Ltd. (UK) Western Drive, Bristol, BS14 0AF, UK Tel: +44 (0) 117 976 7776 rd.sales.uk@spx.com www.radiodetection.com l High accuracy fault location for power and telecom cables. l Wide fault resistance detection up to 200 megohms. l Locates faults between conductors or conductor and metallic sheath, neutral or earth. l Gives high sensitivity to high resistance faults.