HEAT DETECTION IN MOTOR FAN OF THE GEOTHERMAL COOLING TOWER

The main components in a geothermal power plant are the steam turbine, generator, condenser, cooling tower, gas removal system and hydrogen sulfide abatement system. Thermal energy in the form of pressurized steam flows from wells, through pipelines and to the power plant. The steam enters the turbine at 40 - 100 PSI. As the steam expands through the turbine, thermal energy is converted into mechanical shaft energy. The steam turbine is directly coupled to the generator, which converts mechanical energy into electrical energy.

In the cooling tower, there're series of motor to drive the cooling fan. As the fan is critical if it is not working / stucked which will make the temperature raised to critical level whereas the cooling tower constructions are from wood or fiber-glass frame.
Picture - 2 showing fan motor which drives the fan shaft. In this area pull station and linear heat sensor can be installed around the motor body. As the environment in geothermal a bit acidic due to the presence of sulphuric gases, the appropriate model is using fluoropolymer jacket (Protectowire model PHSC-xxx-XCR).

The other places that need linear heat sensor installation are cooling tower structures near the fan rotor and the fan rotor it self. Every components for installing the linear heat sensor shall be made of stainless steel. Protectowire model JD-1 stainless steel clip and stainless steel bolt are used in order to reduce the risk of corrosivity of the corrosive gas, humid and high temperature. Those are conditions accelerate the corrosiveness to the materials.

Each cooling tower has two detection zones plus one pull station. So total we will have eight detection zones. As these zones shall be integrated to the existing fire alarm panel which was Notifier model AM-2020 , PIM-430 becomes the interface module between Protectowire linear heat sensor and Notifier addressable mini input modul model FMM-101. All these assembled into Ex-proof Fiber Reinforced Plastic (FRP) box as shown in Picture - 04. There are eight PIM-430 represent eight detection zone total.