Air turbine start system with monopole starter air valve position

A gas turbine engine system, comprising:

• a gas turbine engine;
• an air turbine starter coupled to the gas turbine engine and comprising a rotationally mounted turbine, the air turbine starter adapted to receive pressurized air and configured, upon receipt of the pressurized air, to direct the pressurized air into the turbine to thereby cause the turbine to rotate at a rotational speed;
• a starter air valve in fluid communication with the air turbine starter and movable between an open position, in which the pressurized air may flow into the air turbine starter, and a closed position, in which pressurized air does not flow into the air turbine starter;
• a monopole sensor coupled to the air turbine starter, the monopole sensor configured to sense the rotational speed of the turbine and supply a rotational speed signal representative thereof;
• and
• a circuit coupled to receive the rotational speed signal and configured, upon receipt thereof, to determine whether the starter air valve is in the closed position or an open position.

An air turbine start system, comprising:

• an air turbine starter comprising a rotationally mounted turbine, the air turbine starter adapted to receive pressurized air and configured, upon receipt of the pressurized air, to direct the pressurized air into the turbine to thereby cause the turbine to rotate at a rotational speed;
• a starter air valve in fluid communication with the air turbine starter and movable between an open position, in which the pressurized air may flow into the air turbine starter, and a closed position, in which pressurized air does not flow into the air turbine starter;
• a monopole sensor coupled to the air turbine starter, the monopole sensor configured to sense the rotational speed of the turbine and supply a rotational speed signal representative thereof;
• and
• a circuit coupled to receive the rotational speed signal and configured, upon receipt thereof, to:
• (i) determine whether the starter air valve is in the closed position or an open position,
• (ii) determine if the air turbine starter is being back-driven, and
• (iii) control pressurized air flow to the air turbine starter, to thereby control turbine acceleration rate and speed.