Air and Gas Starting for G3300B Engines{1451} Caterpillar

Engine:

G3304B (S/N: A4E1-UP)

G3306B (S/N: R6S1-UP)

Introduction

Do not perform any procedure that is outlined in this Special Instruction until the entire Special Instruction has been read and understood.

General Requirements

Illustration 1	g02805819

Air Starter and Components Supplied

The Caterpillar supplied air starting system includes the starter motor, relay valve, control solenoid and a flow matched pressure regulator. These components, properly installed, are compatible for use with either air or natural gas.

There are two options in the starter groups. Refer to Tables 1 and 2.

Note: Also available is the 367-6268 Pressure Regulator

Starter Supply System Operation and Requirements

The flow matched regulator will control upstream starting supply pressure, up to a maximum of 150 psig. The regulator provides flexibility for equipment packages located at sites where the supply pressure of starting gas varies.

The low-pressure turbine starter delivers maximum starting power at 25 psig, which is the maximum operating pressure of the starter. To protect the starter from over pressure, the Cat supplied pressure regulator must be used wherever static upstream starting supply pressure exceeds 25 psig.

To gain the benefits of low-pressure starter operation, use 1.5 inch diameter piping from the source to the starter inlet.

Locate the pressure regulator as close to the engine as possible. However, not closer than 18 inches from the starter.

Where the length of supply piping exceeds 50 ft, a pipe diameter of 2 inches is recommended from the gas source to the regulator.

Sizing of the pipe helps minimize the flow and pressure losses in the system. Using smaller pipe sizes and/or an incompatible pressure regulator will require higher upstream supply pressures.

Gas Starting

For equipment packages operating on field gas pressure, low pressure starting capabilities may eliminate the need for a starting air compressor. The starting option described here may provide engine starting, where electric starting systems and batteries are undesirable or prohibited.

Starter Controls

The starting control system relay valve, solenoid, and engine software provide capabilities to start an engine manually or remotely. The engine software provides a starter lock-out, which includes a ten-second delay between remote start attempts. The lock-out protects the air starter and ring gear from improper engagement after false starts or while the engine is running.

Customer Connections

The turbine air starter motor is tolerant of common gas contaminant liquids, H2S, and fine solids. The turbine normally does not require extensive coalescing filters or scrubbers. Lubricators are never required or used. Install a 40-mesh (400 micron) y strainer upstream of the regulator to protect all components from larger debris, particularly on initial equipment start-up/commissioning. Where supply gas is heavily contaminated with solids such as micro-sand, more frequent checking and cleaning of traps and strainers may be required.

For maximum performance, size the starter exhaust pipe a minimum of 2 inches.

Larger diameters may be required for lengths greater than 100 ft, with the goal of minimizing the back pressure to the starter. For natural gas starting, the starter exhaust and control lines must be routed to a location designated as a safe distance from the unit.

Note: When using any combustible supply gas, follow all applicable regulations and industry safety regulations.

Illustration 2	g02805822
Typical air starting system

Air Starting

Air Tank sizing and Application (70° F)

• Based on installation as specified

• 150 psig air storage pressure

• 20 psig starter operating pressure

• 7 seconds cranking time per start attempt

General

When starting on compressed air, use the same general guidelines. Typically, exhaust piping on air applications may be omitted or abbreviated to a shorter length if advantageous. Since the turbine starter does not use a lubricator, the turbine does not emit an oily mist from the exhaust. Air system contamination and moisture, even heavier amounts, will be passed through the starter exhaust with no detrimental effects to the starter. Direct the exhaust away from areas where personnel may be present.