TEST BENCH DESCRIPTION

 

Reversible: Both sides of the test bench could be used as generator

The configuration of the test bench is back to back, the tested unit is the one that acts as multiplier (generation side), and in this case, we consider the gearbox of the generating side like nº1 and the one of the motor side like nº2. The test must be perform with the two gearboxes on the generator function, this is the reason why the test must be reversible according to a sequence that does not affect the conditions of the same, what means that the gearbox temperatures will not surpass the reached stabilized ones in the other gearbox on each stage, so the initial temperatures of each following test will be never higher to the reached ones in the last stage of the previous test. (Gearbox nº1)

 

 

The gearboxes must be mounted as seemed as possible to their Wind Turbine Platform, all the parts that connect the tested gear box to the bench must be the very same ones, if possible, as in the real wind generator:

 

• -Suspensions (The assembly must be done according to  the corresponding E.P.A. Specifications for Preassembly and Assembly) 
• The locating tolerance value that will be taken by defect is ±1 mm

- Low Speed Train (Interface with the Hollow Shaft of the Gear Box)

• - Conical Coupling

- HS shaft Coupling: must be the one that fulfils the following conditions:

 

Same misalignment angle as in the Wind Turbine
With the same characteristics of rigidity
With the same dynamic characteristics

- Filtering oil Kit and Refrigeration, which will be controlled by a PLC system in order to be “on or off” switched, according to the design requirements of the tested gear boxes.

- Manifold and Oil Filter

 

TEST TOOLS:

All the parts connecting the tested gearbox to the bench should be the same as in the real wind turbine. The low speed shafts of both gearboxes must be coaxial with a maximum deviation of 0.05 mm and the high speed shafts must be parallel with their respective axis on the generator/motors of the bench with a maximum deviation of 1 mm/m.

 

INSTRUMENTATION SPECIFICATION:

The instrumentation is as follows:
Vibrometer: to measure the vibration, the validated equipment for this purpose is the Brüel Kjaer Vibrotester VT60 with uniaxial accelerometers. Other system could be used as long as are contrasted with the VT 60.
- Sound meter: to measure the noise, the following equipment is required: Range: from 20 Hz to 20 kHz Filter: thirds of octave Weighting: Type A for each third of octave as well as for the global value Magnitude: Sound pressure level Unit for third of octave: dBA rms

 

Temperature probes: to measure temperature, 9 channels altogether:

• - 2 x PT100 (HSS bearing and Oil sump)
• - 6 x Contact temperature probes (rest of bearing)
• - 1 x Room temperature probe

All the temperature probes must follow the IEC 751 Class B standard.

 

Pressure meter: To measure the pressure in the manifold. Two kind of pressure meter can be used:

• - Pressure gauges
• - Electronic Pressure Sensors.

 

 

STATIC FLUSHING
Once the gear boxes are fulfilled, the oil must be cleaned using an auxiliary flushing system, in order to obtain an oil cleanliness 17/15/12 according to the ISO 4406.
To ensure the class of the oil, an online oil particles counter will be use, in case of lack of it, oil samples will be sent to an external accredited laboratory.

 

DYNAMIC FLUSHING
The gearboxes must turn without load but increasing progressively the speed until the nominal one, long enough to maintain the oil in the wished cleaning class. 
The initial speed will be of 100 rpm and it will be increased 100 rpm every 2 minutes. The test must last until the cleaning is equal or better than ISO 4406 17/15/12.

 

 

CONTROLS

 

Temperatures: The temperatures will be registered every minute or at least every 5 minutes. The bearings of both gearboxes will be controlled by probes in contact with their outer ring, moreover the oil sump and the ambient temperature will be measured with temperature PT100 gauges.

 

Vibration: The configuration of the vibration measurement equipment is as follows:
Measurement Speed in mm/seg
High pass filter of 2 Hz
Low Pass Filter up to 2000 Hz or 5000 Hz depending of the capability of the equipment
Minimum resolution: 4 Hz
Axial, vertical and horizontal directions:
RMS global value for each 3 step of power, each 3 directions and each 3 shaft. Totally 27 values.Frequency Spectrum for each 3 step of power, each 3 directions and each 3 shaft. Totally 27 values.

 

Sonority: The sonority configuration is as follows:
Measurement range: 20 Hz-20 KHz in 1/3 octaves
Distance to gearbox: 1 m
Measurement point: At HSS height

 

CONTACTS: Once the test is finished, and the gearbox is out of the test bench and without oil, the painted reference teeth will be checked. The planet stage is not controlled; only the two parallel stage. Global pictures of pinion and wheel from the HSS and ISS