RING 2H9155 - Caterpillar

Illustration 1 g06236270
(1) Pilot air solenoid
(2) Controller
(3) Exhaust muffler
(4) Starter inletThe Integral Electronic Controller (IEC) shares control with the engine control system. This control sharing helps provide consistent operation and greater starter reliability. The IEC provides Electronic Starter Protection (ESP) by monitoring starter performance and operation to help prevent damage and excessive wear.Pressurized supply air that is present at the starter inlet valve is routed by a control line to the normally closed pilot air solenoid valve.When the normally closed pilot air solenoid is activated for start-up, the closed pilot air solenoid opens the connected valve. The valve allows the pressurized pilot air to engage the air starter pinion gear.When the pinion is fully engaged, pilot air pressure is directed to the starter relay valve. The supply air pressure fully opens the starter relay valve which allows pilot air pressure to flow through the turbine and crank the engine.Using the 183 tooth ring gear: When the engine begins to run, the engine ring gear will "back drive" the unloaded pinion gear at a ratio of 16.6:1 (Engine RPM X 16.6 = Pinion RPM). To prevent excessive "back driving" and starter overspeed, when the starter reaches a pinion speed of 2800 RPM, the ESP interrupts the electronic signal to the air solenoid, allowing the main relay valve to close and disengage the pinion.When the engine control senses the crank terminate speed, the starting motor solenoid is de-energized. The control valve closes to shut off the main supply of pressurized air to the starting motor.A manual bypass button on the pilot air solenoid will allow the starter to be operated without electrical power and control voltage.
When using the manual bypass, starter overspeed and/or improper starter engagement can occur. Only use the manual bypass in emergencies. Do not use the manual bypass for normal starting.