Governors control the entire operation of the turbine by controlling the input steam to the turbine. Input steam, turbine RPM and output load are balanced by governor, so governor is an important equipment and manufactured only by some developed countries. The cost of governors are very expensive for developing countries. Also service facilities and ready availability are difficult.

Steam turbines are mostly used in sugar factories, chemical and fertilizer companies, oil refineries, ships and rice mills. Each turbine is provided with a governor. There are many models of governors manufactured for different applications. Mostly Woodward hydro-mechanical governors type UG 8,UG 40, PGD, PGPL, PGA, TG 13, TG 17,PSG, SG and Europa governors EHP-34, 1102,1104,1131,1141 are used in steam turbines.

The above hydro-mechanical governors have a 35 year old design but are very reliable and can be understood and serviced by expert mechanics. Periodic service extends the life of the governor beyond 50 years or until the turbine is removed or damaged.

The manufactures designed electronic Governors and obsolete the Hydro- Mechanical Governors. They introduced electronic Governing system consist of three major components. Life cycle is shorter then Hydro- Mechanical Governors. No one can repair the electronic Governors. The model and design of the electronic Governors upgraded every year. When the problem occurs, the customer has to spend lot of money to buy new upgraded model Electronic Governors for old turbine.

Electronic governors are more accurate. Electronic governors are suitable for turbine generators of high capacity above 15 MW, generators parallel with grid as well as multiple generator parallel operations. Hydro mechanical governors are suitable for 200 KW to 5 MW steam turbine generators, steam turbines coupled with pumps, blowers, compressors and sugarcane crushing mills.

Developing countries like India, Malaysia, Thailand, Vietnam, Sri Lanka are producing small steam turbines for power generation. Their small turbines require cheap and reliable hydro-mechanical governors that are easy to grasp and a unit that can be repaired.