About FASTEC Powerflow Electronic Load Governor

The Fastec Powerflow Electronic Load Governor maintains the output of small hydro generators to be at a constant frequency and  voltage.

The speed of these small generators may change as loads drawing power from the system  are switched “on or off”, and this change can  cause significant fluctuations in the  frequency and voltage of  the power supply.

The Fastec Powerflow Electronic Load Governor prevents these fluctuations by instantaneously switching “on” or “off”  a combination of ballast loads that are equal in capacity to the change in the “user” load. The total load on the generator, (and therefore the frequency and voltage supplied), remains constant,  preventing damage or disruption to the circuit or to appliances that are connected to it.

Fastec Powerflow Electronic Load Governors were first installed  in Pakistan by the Agha Khan  Rural Support Programme  (AKRSP).   Today, 15 years later, they continue to give trouble-free operation providing high quality power 24 hours per day to remote communities.    Since that first installation,  Fastec Powerflow has been installed  in many countries, often in remote areas. The ease of transportation, light weight  rugged design and proven reliability  has continually demonstrated that Fastec Powerflow  is the ideal controller  for small hydro systems.

The Fastec Powerflow Electronic Load Governor is available in 50Hz and 60Hz models and can be used with both 1-phase and 3-phase generators. There are two models. The ELG20 will control up to 20Kw and the ELG35 will control up to 35Kw. One Fastec Powerflow is connected to each phase in a 3-phase installation. Multiple units can also be connected per phase. The Fastec Powerflow will control systems from 5Kw to over 100Kw

    • Fully electronic with no moving parts
    • Single or three phase.
    • Self diagnostic function which shows any faults in the ballast load  circuits or fuses
    • All load circuits are  fuse protected
    • Over or under speed LED indicator display
    • Zero voltage switched; low RFI prevents radio and TV static.
    • Operates at unity power factor.
    • Operating voltage 120 or 240 volts AC Operating frequency band : 49.3 – 50.7, (50Hz)   or 59.3 – 60.7, (60 Hz)
    • Frequency   +/ –  1.5%  for 3% total droop
    • 7 ballast load channels  plus one half load, giving 15 individual load steps
    • The ballast load priority function allows loads to be selected in order for application
    • Turbine generator output is controlled  up to 20 or 35 kW per phase depending on the model
    • Maximum ambient temperature of 45 deg C
    • Robust extruded aluminium heatsink
    • The system becomes active at approximately 100 volts AC and will accurately monitor frequency as soon as there is sufficient voltage generated by the turbine to drive the printed circuits. The frequency sensing circuitry accepts voltages from l00 to 400 V AC as well as those with  distorted waveforms.  It is able to operate on any type of alternator with or without an automatic voltage regulator (AVR).

Weight 9Kg
Dimensions Height 395mm Width 265mm Depth 140mm


Fastec Powerflow Electronic Load Governors have been installed in many countries, often in remote areas where small hydro systems are the only option for power supply  Fastec Powerflow Electronic load Governors are in use in Vietnam, Papua New Guinea, Sweden, Ireland, North and South America, Australia and New Zealand and other countries.  A small installation in Nepal is typical. Before Fastec Powerflow was installed, the system had to be controlled with a hand operated valve which was used to regulate the flow through the turbine as a means of maintaining the turbine speed as the load changed. But the response time was slow, so fluctuations still occurred and at night the system was shut down as there was no one to operate the valve. Lights burnt out frequently, equipment was damaged, and in the evening when power would have been most useful, there was none. When Fastec Powerflow was installed, a stable  power supply became available 24/7. Reading and education could take place in the evening, and because the supply had become reliable, a small water purification business was established which quickly became profitable. The initial investment was quickly repaid and the system still continues in operation.