# US 5,345,358 A · Method for evaluating operability of filter components in power conversion system

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- Number: US 5,345,358 A
- Document ID: US5345358A
- Status: Granted
- Kind: A
- Application number: 08/022,254
- Filed: 1993-04-09
- Granted: 1994-09-06
- Earliest claimed: 1991-03-08
- Assignees: General Electric Company
- Inventors: Ajith K. Kumar
- Web page: https://patentgrep.com/patent/US5345358A

## CPC

- B60L 7/003: {Dynamic electric braking by short circuiting the motor}
- B60L 3/00: Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption (methods or circuit arrangements for monitoring or controlling batteries or fuel cells B60L58/00)
- B60L 7/14: for vehicles propelled by AC motors
- B60L: PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES (arrangements or mounting of electrical propulsion units or of plural diverse prime-movers for mutual or common propulsion in vehicles B60K1/00, B60K6/20; arrangements or mounting of electrical gearing in vehicles B60K17/12, B60K17/14; preventing wheel slip by reducing power in rail vehicles B61C15/08; dynamo-electric machines H02K; control or regulation of electric motors H02P); SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES (electric coupling devices combined with mechanical couplings of vehicles B60D1/64; electric heating for vehicles B60H1/00); ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL (control or regulation of electric motors H02P); MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES

## Abstract

A method for measuring capacitance in a power conversion system by measuring the time rate of discharge of the capacitance means and computing the value of capacitance corresponding to the measured discharge rate and a method for verifying that a filter in the power conversion system is effective for suppressing preselected frequencies corresponding to signalling frequencies used in a transit system. In this latter form, the system periodically initiates a self-test function in which the preselected frequency is injected into the system for verifying that the system will detect signals at the preselected frequency.

## Claims

### Claim 1

A method for verifying operation of a frequency monitoring system in an electric propulsion system for a transit vehicle receiving power from a wayside conductor, the monitoring system including a detector for providing signals representative of the frequency of alternating current power introduced to the wayside conductor by the propulsion system, at least one band-pass filter for extracting from the detector signals selected signals within the pass-band of the filter, apparatus for determining the presence of such selected signals and for disabling the propulsion upon determination of such presence, the method including the steps of:
periodically interrupting the signals from the detector to the band-pass filter;
injecting signals of the selected frequency into the band-pass filter and verifying detection of the presence of the injected signals at the determining apparatus; and
coordinating the injecting step with the apparatus to inhibit disabling the propulsion system if such detection occurs and immediately disabling the propulsion system if the injected signal is not detected by the apparatus.