FORM 2
THE PATENTS ACT, 1970 PROVISIONAL SPECIFICATION
(See Section 10)
AUTO DETECTION OF CURRENT SENSOR MODULE
Numbered as dated
INVENTORS:
1. MANDARGADGIL
APPLICANT:
M/s. LARSEN & TOUBRO LIMITED
L&T House, Ballard Estate, P.O. Box No 278,
Mumbai, 400 001, Maharashtra,
INDIA


AUTO DETECTION OF CURRENT SENSOR MODULE
A) TECHNICAL FIELD:
[0001] The present invention generally relates to a sensor detection system more particularly to a design of sensor detection circuit for automatic detection of main sensor system by main protection system in a low voltage motor control applications.
B) BACKGROUND OF THE INVENTION:
[0002] An electrical control system is used mainly for protection and metering purposes, there is a constant need of field up gradation of the relay in the control systems which cater with larger range of motors. That means the relay used has to cater to large input current ranges starting from the lowest rated motor to the highest rated motor rated currents. This large dynamic range needs to be mapped to the finite, defined resolution and limited range of reference voltage which can be supplied to the digitization section comprising of microcontroller/ microprocessor.
[0003] This can be addressed with the use of various current sensors which can easily cater to this wide dynamic range without saturation. These current sensors are again classified by accuracy range bands which exist due to variations in manufacturing process and inherent properties of the sensor materials. This means there can be multiple sensors of varying electrical specifications that can be interfaced to the same protection module.


Usually it is the responsibility of the user to ensure that the proper sensor module is being interfaced to the protection release & respective protection current settings are fed to the protection module.
[0004] This gives rise to manual intervention & in case of mismatch or incorrect settings the results could be hazardous, load may burn, protection may not work etc. Hence if the settings are authenticated with respect to the sensor automatically then possibility of wrong settings gets eliminated. This gives rise to the need of identifying the type & range of sensor module.
[0005] Prior art discloses a Motor protection unit with integrated current and voltage sensors integrated there on. The integrated current and voltage measuring device produces primary current and voltage representative signals to on-board electronic devices in order to realize the measure, process and protection functions as a whole. But some times the current sensors need to be changed to match the type of the 3 0 AC motor to be protected , this gives rise to manual intervention & in case of mismatch or incorrect settings the results could be hazardous, load may burn, protection may not work etc.
[0006] In a conventional hardware system current sensors and burdens corresponding to a current sensor needs to be changed at manufacturing points and in case of input range change of an application complete current sensing circuit needs to be rewired and re soldered.


[0007] None of the prior art discloses an automatic detection of main sensor system in a low voltage motor control applications. Hence there is a need to develop a system which can be used as an interface between the high voltage and high current lines and protection unit to reduce the operator intervention to eliminate the possibility of wrong settings resulting from human intervention. Hence there is a need to automatically authenticate the settings with respect to the sensor to identify the type and range of the sensor modules used in control units.
C) OBJECT OF THE INVENTION:
[0008] The primary object of the present invention is to design a Sensor detection circuit for automatic detection of main sensor system in a low voltage motor control applications.
[0009] Yet another object of the present invention is to interface the sensor detection circuit to main protection release to automatically detect the type and accuracy range of the current sensors to ensure definite and guaranteed class of overall system accuracy in a low voltage motor control applications.
[0010] Yet another object of the present invention is to ensure whether the proper sensor module is being interfaced to the protection release and respective protection current settings are fed to the protection module.


[0011] Yet another object of the present invention is to authenticate the settings automatically by using sensor and hence to eliminate wrong settings by human intervention.
D) SUMMARY OF THE INVENTION
[0012] Sensor detect circuit is designed to automate the detection of main sensor system consisting of current transformers by the main protection release in a low voltage motor control application. The circuit eliminates online sensor identification by the user. It requires only initialization of few switch settings of the sensor module prior to the installation. After interfacing it to the main protection release it automatically detects the type and accuracy range of current sensor. A Sensor detection circuit is interfaced between high voltage, high current lines and protection unit to reduce the operator intervention in a dangerous wire harness thus providing user safety. The maintenance and operation of the system becomes modular since it can be directly installed with high current carrying harness.
[0013] The current sensors and burdens corresponding to a current sensors in a conventional hardware system is replaced with a compact more user programmable system where overall metering accuracy of a system is guaranteed at run time by detecting an accuracy range of input sensor system and protection factors can be calculated with more precision. As this is a common circuit for all range of current


transformers and Burdon, there is no need to maintain different inventory of separate current transformer with separate boards significant cost reduction is possible.
The detailed description of the invention shall be illustrated in detail at the time of filing Complete Specification.