Browse Prior Art Database

Integrity Checker for Magnetic Vehicle Detector

IP.com Disclosure Number: IPCOM000094816D
Original Publication Date: 1965-Jun-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

French, WK: AUTHOR

Abstract

While the integrity of a magnetic vehicle detector can be checked by driving a vehicle over the roadway in which the sensing coils are buried, it is more expedient to provide an extra loop in the roadway and a shorting switch at the control box. The serviceman can thus simulate the presence of a vehicle and check the operation of the detector.

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Integrity Checker for Magnetic Vehicle Detector

While the integrity of a magnetic vehicle detector can be checked by driving a vehicle over the roadway in which the sensing coils are buried, it is more expedient to provide an extra loop in the roadway and a shorting switch at the control box. The serviceman can thus simulate the presence of a vehicle and check the operation of the detector.

As shown, the usual vehicle detector consists of oscillator 10 feeding transmitting coil 11 buried in the roadway. Receiving coil 12, also buried in the roadway and connected as part of a tuned circuit, is coupled to coil 11. The presence of a vehicle changes the coupling between the coils to operate detector circuits 13 to signal the vehicle's presence.

A third, single turn coil 14 with leads to the control box is serially connected to resistor 15 and switch 16. By appropriate adjustment of the value of resistor 15, closure of switch 16 provides a shorted, single turn in the magnetic field produced by transmitter coil 11 and effects the same loading upon detector coil 12 as would the presence of a vehicle.

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