Interested in learning more about gear speed reducers for application on air cooled condensers? If so, CTI has the perfect resource paper to utilize! 

What are Gear Speed Reducers? 

A gear speed reducer is defined as a mechanical gear train that is located between the motor and a piece of machinery that is used to reduce the transmission speed of power. Gear speed reducers are available in many shapes and sizes, and are typically used in steel facilities, ships, cranes, elevators, and conveyors. 

Additionally, all gear speed reducers are considered gearboxes, but not all gearboxes are speed reducers. A gearbox is a box that consists of gears along with a gear train. It also changes the force of rotation (or torque) and speed between a motor and a load. Not all gearboxes are speed reducers because they may not reduce the speed of the input. 

What are Air Cooled Condensers? 

Air cooled condensers (ACC) are direct dry cooling systems in which steam is compressed inside large, finned air-cooled tubes. There are 7 major components to an air cooled condenser: ducting (transports the steam), finned tube heat exchanger, axial fans, motors, gear speed reducers/gearboxes, piping, and tanks (to collect the liquid condensation). The air flows across the finned tubes using the axial fans to condense the steam. The condensation is then collected in the tanks and is recycled into the necessary different utilities. The air flow outside the tubes is what actually removes the heat and is essentially the function of an ACC. 

Why are Gear Speed Reducers Important? 

First, these types of gear take the force of rotation (or torque) created by the power source and duplicate it. Then they reduce the speed of the input so that the output is working at the correct speed. The main reason that gear speed reducers are so important is that they reduce the speed of an electric motor in the machine so that it can run safely and efficiently. 

When applying gear speed reducers, particularly helical, to air cooled condensers, it is important to maintain an adequate oil temperature. With this being said, it is essential that either synthetic oil or grease is used as this prolongs the life of the gear speed reducer. 

Additionally, make sure that the gear speed reducers that are being utilized specifically for air cooled condensers. Do not use “multipurpose” gear speed reducers as they may not have the proper bearings for the fan thrusts inside the air cooled condenser tubes. Furthermore, make sure that all gear speed reducers are in accordance with AGMA standards and guidelines. 

If an air cooled condenser is ever shut down, precautions should be taken, especially if a shutdown period lasts a week or longer. Always check with the manufacturer for specific recommendations concerning protection during a shutdown. 

For longer periods of time (more than one year+) between installation and operation of the gear speed reducer, it may be necessary to coat the gear speed reducer internals with a rust preventative or add a vapor phase rust inhibitor to the oil. For short-term shutdowns (less than 1 year but longer than one week), the preferring procedure is to operate the gear speed reducer weekly for several minutes to recoat the gear speed reducers’ internal parts with lubricant. This will also help protect the electric motor by evaporating the condensed moisture. 

CTI Resource on Gear Speed Reducers 

Detailed inside the resource paper, is an overview of gear speed reducers when applying these devices on air cooled condensers. In particular, this document covers the minimum recommended rating practices and operating considerations for helical gear speed reducers, covers the parallel shaft design, and explains when reducers are used with propeller-type fans on air cooled condensers. With this being said, it is important to pay attention to the gear speed reducers when they are installed on air cooled condensers because this will assure reliability, give the reducer a longer service life, and will require minimal maintenance. 

Are you interested in learning more about gear speed reducers for air cooled condensers? If so, purchase the full standard here! 

In this publication, another CTI Paper (TP97-10) titled “Mechanical Damage Caused by EMF Generated from Fast Bus Reclosure” is also talked about. Click here to purchase this paper. 

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