Francis turbine is suitable for middle and high water head, from 15 meter to 300 meters. The merits of this turbine include good operation stability, impacted structure, and relatively higher average efficiency. Vertical and horizontal shaft arrangements are both available. It is one of the most widely used turbines.

HLA551C-WJ-50 Francis Horizontal Shaft Hydraulic turbine
1. Guaranteed Turbine Performance
Output:
At hereunder listed water head and tailwater level, when turbine run at rated speed 1000rpm, and the Cavitation Erosion is in permitted range, the output is:
 

Net water head (m)	Output (kw)	Max. Output (kw)
Designed Water head 33.7	543.3 kW	574.3

Efficiency:
At rated head 33.7 m, rated output 543.3kW, the guaranteed prototype turbine efficiency is no less than 89%, under the same operation condition the model turbine efficiency guaranteed value is no less than 92%.
Under all operation range, the prototype turbine max. efficiency guaranteed value is no less than 89%, model turbine max. efficiency guaranteed value is no less than 92.7%.
Regulation Guarantee
  At 33.7 m water head, 543.3 KW output, when dump full load, the maximum speed rise will not exceed 60%. At 33.7 m water head, 543.3 KW output, when dump full load, the maximum pressure rise at the spiral case will not exceed 50%.  
2. Turbine Technical Data Details
Model                                        HLA551C-WJ-50, Francis Horizontal Shaft
Runner Pitch Diameter D:                                             60cm
Rotation Direction if viewing from the ND end of the generator:             CW
Rated Speed                                                        1000rpm
Specific Speed at rated water head 33.7 m with rated output               543.3 m.kW
Discharge at rated water head 33.7 m with rated output                         1.84 m3/s
Max. Runaway Speed (guide vane at max. unit runaway open degree position, generator with empty load, max. water head)                     1962r/min
Turbine Air Admission Type                   Natural Air Admission
The Noise at 1.0 meter distance from the spiral case does not exceed     85dB(A)
Max. Leakage when the Guide Vane is Closed                          4.5 L/S
Weight of Rotary Parts (Runner)                                      0.3T
Total Weight of the Turbine                                           6.3 T
Max. Lifting part in the powerhouse for the main crane             4.5T (Spiral case assembly)
Runner Material                                               ZG0Cr13Ni4Mo
Main shaft material                                            20SiMn
Main shaft seal method                                        labyrinth + Water Splash ring
Guide Bearing Type
  Material                     Thrust bushing and radial bushingare both Babbit alloy metal Cooling water consumption                                    30 L/min Cooling water pressure                                        0.2~0.3MPa Oil Volume                                                   200 L Oil No.                                                       46# Turbine Oil Spiral Case
  Material                                                    16Mn Drainage Equipment                                         Nature drainage Draft tube material                                                 16Mn
Water Distributor Mechanism
Material
  Guide Vane:                                                 ZG0Cr13Ni4Mo Front, back cover:                                            ZG230-450 Guide Vane Shaft Bushing:                                    GS-2
3. Type and Rated Value
  Turbine is horizontal shaft Francis type, couple with generator via flexible coupling. Rotation direction is clockwise if viewing from generator end. At rated head of 33.7 m and rated flow of 1.84 m3/s, when the rotation speed is 1000 rpm, the guaranteed turbine output is not less than 100% of rated value. When operation head is bigger than rated head, the maximum output of the generator is no less than 110% rated value, for long time operation. 3. Rotation Speed
Rated Speed:  The rated speed of the turbine is 1000rpm.
Runaway speed：Operating with empty load, Max head of 33.7m, with guide vane full open, the Max. runway speed does not exceed 1962 rpm. All rotation of the unit can withstand safely this runaways speed for 3 minutes without causing harmful distortion.
4. Efficiency
The guaranteed efficiency value at rated head of 33.7 m, with 543.3KW rated output is not less than 89.3%.
When the turbine operates at design head of 33.7 m, the maximum efficiency guaranteed value should not be less than 90%.
5. Stability and Noise
When the load is within 45% to 110% of rated output range, the turbine can operate stably.
The stability criteria include Spiral case vertical vibration and water guide bearing throw.
  Under various operation condition, including dump load, each part of the turbine should not incur resonance and harmful distortion. The top cover vibration and main shaft throw does not exceed allowed value as specified in the GB8564 standard. Within all operation range, the noise, as measured at 1 meter distance vertically and horizontally from the generator spiral case, does not exceed 85 dB.
6. Reliability of the turbine
The overhaul interval of the turbine is 5 years.
Total Service Life is 40 years