Diagnostic device for gas turbine ignition system

An apparatus for monitoring the operation of an ignition system for a turbine engine comprising a first igniter plug and a first exciter, where the first exciter provides a series of high energy pulses to the first igniter plug for igniting the fuel of the turbine engine, the apparatus comprising:

• a first detector for detecting voltage levels for the high energy pulses that are less than a predetermined value representing a nominal minimum voltage generated by the first exciter when it is healthy;
• a second detector responsive to the first detector for detecting a persistent condition of voltage levels for the high energy pulses that are less than the predetermined value and providing a signal indicative thereof;
• and
• diagnostic means responsive to the signal of the second detector for reporting failure of the exciter.

An apparatus for monitoring the operation of an ignition system for a gas turbine engine comprising a first igniter plug and a first exciter, where the first exciter provides a series of high energy pulses to the first igniter plug for igniting the fuel of the turbine engine, the apparatus comprising:

• a first detector for detecting the discharging of the high energy pulses at a rate much less than a predetermined rate representing a nominal minimum rate of discharge for the first igniter plug when it is healthy;
• a second detector responsive to the first detector for detecting persistent and non-persistent conditions of discharge rates for the high energy pulses that are less than the predetermined value and providing signals indicative of each condition;
• and
• diagnostic means responsive to the signals for reporting 1) impending failure of the igniter plug in response to the presence of the non-persistent condition and 2) failure of the igniter plug in response to the presence of the persistent condition.

A method of diagnosing the state of health of an igniter plug connected to a remaining portion of an ignition system for a turbine engine by way of an output connector, the method employing a transportable diagnostic test equipment, which includes an exciter for generating a series of high energy pulses, the method comprising the steps of:

• disconnecting an input of the igniter plug from the output connector of the ignition system without removing the igniter plug from its engine mounting;
• attaching the diagnostic test equipment to the input of the igniter plug;
• supplying the series of high energy pulses to the igniter plug by way of the diagnostic test equipment;
• detecting persistent voltage values for the high energy pluses in the series that are less than a value representing a nominal minimum voltage generated by the exciter when it is healthy and in response thereto indicating that the exciter has failed;
• and
• detecting persistent discharge rates of the high energy pulses in the series that are mush less than a rate representing a nominal minimum rate of discharge for the igniter plug when it is healthy and in response thereto, and in the absence of an indication that the exciter has failed, indicating that the igniter plug has failed.

A method of diagnosing the state of health of an igniter plug for an ignition system of a turbine engine, the method employing a transportable diagnostic test equipment which includes an exciter for generating a series of high energy pulses, the method comprising the steps of:

• removing the igniter plug from the environment of the ignition system;
• attaching the plug to the transportable diagnostic test equipment;
• supplying the series of high energy pulses to the igniter plug by way of the diagnostic test equipment;
• detecting persistent voltage values for the high energy pulses in the series that are less than a value representing a nominal minimum voltage generated by the exciter when it is healthy and in response thereto indicating that the exciter has failed;
• and
• detecting persistent discharge rates of the high energy pulses in the series that are much less than a rate representing a nominal minimum rate of discharge for the igniter plug when it is healthy and in response thereto, and in the absence of an indication that the exciter has failed, indicating that the igniter plug has failed.

An ignition system having the ability to diagnose the state of health of an igniter plug of the system by monitoring an ignition waveform generated at a location in the system electrically remote from a high energy pulse at the igniter plug and environmentally isolated from the plug, the ignition system comprising:

• means for generating a series of the high energy pulses for initiating spark events at the igniter plug;
• a cable for communicating the high energy pulses to the plug;
• a series of the ignition waveforms created within the generating means in connection with the generation of the series of high energy pulses, where each of the waveforms is associated with one of the high energy pulses;
• a first device for monitoring the series of waveforms and detecting abnormalities in the waveform;
• and
• a second device for diagnosing the state of health of the igniter plug in response to repeated detection of the abnormalities in the series of waveforms created by the generation of the series of high energy pulses.