Title of Invention

ISOLATED MEASAUREMENT CIRCUIT FOR SENSOR RESISTANCE

Abstract The invention relates to measuring the resistance of a resistive sensor, such as a PTC or NTC temperature sensor used for monitoring the temperature of the windings of an electric motor. The invention is based on an electronic circuit in which conductors from a sensor located in the object to be monitored are connected to an amplifier circuit in a feedback configuration that reduces the DC level supplied to the voltage divider when the sensor resistance increases. The measured signal is amplified and, using a comparator to compare it with the output voltage of a sawtooth generator, a continuous PWM (Pulse Width Modulation) signal is generated and transmitted in digital format to a SELV electronic circuit, for example through an opto-isolator. The essentially logarithmic signal amplification makes it possible to reliably distinguish between a short circuit in the sensor circuit and low values of sensor resistance
Full Text

Documents:

4510-CHENP-2006 AMANDED CLAIMS 03-03-2010.pdf

4510-CHENP-2006 CORRESPONDENCE OTHERS 01-12-2009.pdf

4510-CHENP-2006 CORRESPONDENCE PO.pdf

4510-CHENP-2006 DESCRIPTION (COMPLETE) GRANTED.pdf

4510-CHENP-2006 EXAMINATION REPORT REPLY RECIEVED 03-03-2010.pdf

4510-CHENP-2006 FORM-1 08-12-2006.pdf

4510-CHENP-2006 FORM-18.pdf

4510-CHENP-2006 FORM-3 03-03-2010.pdf

4510-CHENP-2006 FORM-5.pdf

4510-CHENP-2006 POWER OF ATTORNEY.pdf


Patent Number 239966
Indian Patent Application Number 4510/CHENP/2006
PG Journal Number 17/2010
Publication Date 23-Apr-2010
Grant Date 16-Apr-2010
Date of Filing 08-Dec-2006
Name of Patentee ABB OY
Applicant Address STROMBERGINTIE 1, FI-00380 HELSINKI, FINLAND
Inventors:
# Inventor's Name Inventor's Address
1 LAAKSO, KARI-MATTI ITARANNANTIE 93, FI-68660 PIETARSAARI, FINLAND
2 BERTS, ANDREAS GAMMELSTADTSVAGEN 31 B, FI-65610 KORSHOLM, FINLAND
PCT International Classification Number G01K 7/22
PCT International Application Number PCT/FI05/00267
PCT International Filing date 2005-06-08
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 20040802 2004-06-10 Finland