Claims:WE CLAIM:

1. Torque measurement validation setup for hydro-machine model test rig comprises of torque measurement, T12 torque meter [2] installed on the input shaft [1A] of model bearing [1], the input shaft [1A] is fitted in inner race of bearing [4], a thrust collar [7] sits on outer race of the bearing [4], a plate [8] is placed on the thrust collar [7], a pair of weight blocks [5] are connected to the plate [8] on both sides thereof, a motor [3] is connected to input shaft [1A] of model bearing [1] together with flange [9 ] and universal coupling [10 ] arrangement.

2. The Torque measurement validation setup for hydro-machine model test rig as claimed in claim 1, wherein the external variable speed motor [3] with electronic/electrical drive [6] is provided to obtain desired input torque and speed.

3. The Torque measurement validation setup for hydro-machine model test rig as claimed in claim 1 or 2, wherein the torque value from T12 torque meter [2] is used as standard value of input torque to the model bearing [1].

4. The Torque measurement validation setup for hydro-machine model test rig as claimed in claims 1-3, wherein the validation system has two set up including Torque measurement validation setup without axial hydraulic thrust and Torque measurement validation setup with axial hydraulic thrust using thrust collars with weight.

5. The Torque measurement validation setup for hydro-machine model test rig as claimed in claim 4, wherein the First setup without axial hydraulic thrust comprises of Electrical drive to control speed and torque (6), Electric motor with capacity of 90 kw (3), Torque-meter (T12) (2), Universal joint or flexible coupling (8) and Model bearing (1).

6. The Torque measurement validation setup for hydro-machine model test rig as claimed in claim 4, wherein the Second setup with axial hydraulic thrust using thrust collars comprises of Electrical drive to control speed and torque (6), Electric motor with capacity of 90 kw (3), Universal joint or flexible coupling (10), Bearing and thrust collar for axial thrust application (4), (7), Weights to simulate axial hydraulic thrust (5), Torque-meter (T12) (2) and Model bearing (1).
, Description:¬FIELD OF INVENTION:
[001] This invention relates to Torque measurement validation setup for hydro-machine model test rig.

BACKGROUND OF INVENTION:
[002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.

[003] Hydro Turbine models are tested to evaluate the performance of the turbine. The performance of the prototype can be established on the basis of model test results. Hydraulic torque is evaluated from model test which gives very crucial input for prototype performance.

[004] The hydraulic torque on runner is exerted by dynamic action of flowing water. This torque can be evaluated from model test. IEC 60193 provides the procedure for model test torque measurement. IEC has recommended the use of dynamometer and model bearing for measurement of hydraulic torque at the stator of generator.

[005] However, the challenge has always been to calibrate and measure the torque on runner shaft directly. As per current practice, torque measurement is carried out at the stator of the motor/generator. Torque is transmitted through model bearing, rotor of the motor/generator and stator to the measurement instrument. There may be losses in such transmission of torque, which may lead to inaccurate hydraulic torque measurement. Hence, a setup was designed and manufactured for Periodic Validation of torque measurement.

Existing torque measurement setup as per IEC 60193 (by dynamometer/model bearing)
[006] Reference may be made to Figure 1 indicating the following features:
1 rotating part
2 swinging frame
3 stationary part
4 bearing of rotating part in balance
5 mechanical seal in balance
6 low friction bearing of the swinging frame
7 labyrinth seal, membrane
11 axial thrust bearing
— – — reference section for torque measurement

[007] In this known set-up, there is a generator-motor assembly whose rotating part [1] is directly coupled with turbine runner and swinging frame [2] which is free to rotate with the help of low friction bearing [6] and isolated from stationary part [3]. Torque is transmitted from hydro turbine runner (prime mover) through bearing of rotating part [4] to rotating part [1] of the generator-motor assembly and further to the swinging frame [3], which is connected to measurement lever arm and load cell. The actual force applied to balance the swinging frame [2] is measured by Load cell transducer. Axial thrust bearing [11] is used to take any axial load and restrict vertical movement and labyrinth seal and membrane [7] restricts water flow from turbine to bearing of rotating part [4].

[008] Torque T is determined by the force F applied to a lever arm multiplied by the radius r at which it is applied i.e. T = r x F.

[009] The calibration of load cell is performed with pre-calibrated weights, while the shaft is stationery or rotating at very low speeds. Model bearing is mandatory equipment in model test rig, which works as guide cum thrust bearing and also stops water leakage from the system. Also there is a setup to eliminate the effect of friction torque on absolute value of transmitting torque.
PRIOR ART:

[0010] Some patents for torque measurement techniques are discussed herein below:

[0011] CN101487751B: Measuring apparatus for frictional moment of bearing under different axial loads and rotation speeds.
[0012] The invention relates to a device for measuring friction torque of a bearing under different axial load and revolution speed, comprising a fixing component, an axial loading component, a display component and a measurement component arranged on a stander base, wherein, the measurement component is arranged in a bearing support by an upper bearing and a lower bearing which are the same and fixed on a stander workbench, a bushing on the workbench supports the end face of the bearing outer ring of the lower bearing, so as not to contact the end face of the inner ring, and a loading head presses the end face of the bearing outer ring of the upper bearing.

[0013] US20110015878A1: Rotational torque measurement device.
[0014] The invention provides a device for measuring the torque applied through a rotating member rotating about a longitudinal axis, relative to a fixed member.
[0015] However, none of the above can fulfill the requirements of the invention for which it has been devised. Hence, the present invention has been introduced.

OBJECTS OF THE INVENTION:

[0016] An object of the invention is to provide Torque measurement validation setup for hydro-machine model test rig.
[0017] Another object of the invention is to provide Torque measurement validation setup for hydro-machine model test rig, which obviates shortcomings of the prior art(s).
[0018] Yet another object of the invention is to provide Torque measurement validation setup for hydro-machine model test rig, which is simple in construction.
[0019] Still another object of the invention is to provide Torque measurement validation setup for hydro-machine model test rig, which accurately measures Torque.
[0020] These and other objects and advantages of the present invention will be apparent to those skilled in the art after a consideration of the following detailed description taken in conjunction with the accompanying drawings in which a preferred form of the present invention is illustrated.

SUMMARY OF THE INVENTION:

[0021] One or more drawbacks of conventional systems and process are overcome, and additional advantages are provided through the apparatus/composition and a method as claimed in the present disclosure. Additional features and advantages are realized through the technicalities of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered to be part of the claimed disclosure.

[0022] According to this invention, there is provided Torque measurement validation setup for hydro-machine model test rig comprises of torque measurement, T12 torque meter [2] installed on the input shaft [1A] of model bearing [1], the input shaft [1A] is fitted in inner race of bearing [4], a thrust collar [7] sits on outer race of the bearing [4], a plate [8] is placed on the thrust collar [7], a pair of weight blocks [5] are connected to the plate [8] on both sides thereof, a motor [3] is connected to input shaft [1A] of model bearing [1] together with flange [9 ] and universal coupling [10 ] arrangement.

[0023] The external variable speed motor [3] with electronic/electrical drive [6] is provided to obtain desired input torque and speed.

[0024] The torque value from T12 torque meter [2] is used as standard value of input torque to the model bearing [1].

[0025] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

[0026] It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined to form a further embodiment of the disclosure.

[0027] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:

[0028] The illustrated embodiments of the subject matter will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and processes that are consistent with the subject matter as claimed herein, wherein:-
Figure 1 shows: Existing torque measurement setup as per IEC 60193.
Figure 2 shows: schematic diagram of Torque measurement validation setup according to the present invention.
Figure 3 shows: Torque measurement validation physical setup and electrical drive of the present invention.
Figure 4 shows: Torque measurement plot by LabVIEW.
Figure 5 shows: Torque measurement plot by LabVIEW showing influence of friction torque transfer system.

[0029] The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAIL DESCRIPTION OF INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS OF THE PREFERRED EMBODIMENTS:

[0030] While the embodiments of the disclosure are subject to various modifications and alternative forms, specific embodiment thereof have been shown by way of example in the figures and will be described below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the scope of the disclosure.

[0031] Runner Hydraulic torque can be estimated experimentally in hydro-machine model testing. Precise measurement of hydraulic torque is critical to evaluation of hydro turbine efficiency. IEC has recommended the use of dynamometer and model bearing for measurement of hydraulic torque at the stator of generator as a primary method. The measurement is susceptible to inaccuracies due to not measuring directly the shaft torque at runner and unable to do calibration in rotating shaft.

[0032] Now, reference may be made to Figure 2 illustrating the validation system of the present invention, which indicates the following features:
- Bearing Assembly (1)
- input shaft [1A]
- Torque-meter (T12) (2)
- Electric motor with capacity of 90 kw (3)
- Weight blocks (5)
- Electrical drive to control speed and torque (6)
- Bearing (4) and thrust collar (7) for axial thrust application
- Plate [8]
- Flange [9]
- Universal coupling [10]

[0033] To validate torque measurement, T12 torque meter [2] is installed in the system on the input shaft [1A] of model bearing [1]. The torque value from T12 torque meter [2] is used as standard value of input torque to the model bearing [1]. As it is not possible to do this validation during normal model test with water flow, external variable speed motor [3] is used with electronic/electrical drive [6] so that desired input torque and speed can be achieved. Normally model turbines are run at 600 to 800 rpm, but validation is done at speeds of 500 rpm or less considering the limitation of the external motor drive system.

[0034] When hydro-machine runs there is a downward axial hydraulic thrust. To study the effect of this thrust, thrust collar [7] with pan for weight [5] are added to the validation system along with a bearing [4] as shown in the figure 2. The input shaft [1A] is fitted in inner race of the bearing [4]. The thrust collar [7] sits on outer race of the bearing [4]. A plate [8] is placed on the thrust collar [7]. A pair of weight blocks [5] are connected to the plate [8] in hanging position.

[0035] The motor [3] is connected to input shaft [1A] of model bearing [1] together with flange [9] and universal coupling [10] arrangement.
[0036] Validation of Runner Hydraulic torque measured from existing set-up can be done experimentally. Instead of using actual hydro turbine model an equivalent set-up is proposed in the invention. This validation system has two below set up:
- Torque measurement validation setup without axial hydraulic thrust.
- Torque measurement validation setup with axial hydraulic thrust using thrust collars with weight.

First setup without axial hydraulic thrust comprises of:

- Electrical drive to control speed and torque (6): As it was not possible to do this validation during normal model test with water flow, external variable speed motor is used with electronic drive so that desired input torque and speed can be achieved.

- Electric motor with capacity of 90 kw (3) : To simulate input torque , this device is equivalent to runner (prime mover),

- Torque-meter (T12) (2): The torque value from T12 torque meter is used as standard value of input torque to the model bearing.

- Universal joint or flexible coupling (10)

- Model bearing, (1)

Second setup with axial hydraulic thrust using thrust collars comprises of:
- Electrical drive to control speed and torque (6): As it was not possible to do this validation during normal model test with water flow, external variable speed motor is used with electronic drive so that desired input torque and speed can be achieved.

- Electric motor with capacity of 90 kw (3): To simulate input torque, this device is equivalent to runner (prime mover).

- Universal joint or flexible coupling (10)

- Bearing and thrust collar for axial thrust application (4), (7)

- Weights to simulate axial hydraulic thrust, (5)

- Torque-meter (T12) (2): The torque value from T12 torque meter is used as standard value of input torque to the model bearing.

- Model bearing (1)

Working of Invention:

[0037] To simulate input torque device (runner), an electric AC motor has been used, which has capacity of 90 kw and with the help of variable frequency drive the speed of the motor is controlled.

[0038] Speed of validation motor and test bed DC motor (dynamometer) is increased simultaneously maintaining the same speed so that there is no or minimum torque in the system. Once the desired speed is reached, speed of one of the motor is decreased slightly to introduce torque in the system. Speed variation is achieved with the help of variable frequency drive. Now torque measurements were carried out from both T12 and the existing torque measurement system (on the stator of dynamometer) simultaneously and the readings were compared.

[0039] The experimental study can be conducted at different shaft speeds and axial loading. Validation of existing torque measurement setup can be done with the help of Torque measured from T12 torque meter and evaluate the error if any.

Advantages of Invention:

[0040] The validation setup thus developed can be used to validate existing torque measurement with the help of measured torque from T12 torque meter. It is also recommended that torque measurement system validation be carried out periodically using this set up and be a part of IEC 60193 as a standard test procedure.

[0041] Further, the set-up of the instant invention is simple in construction and provides accuracy in measurement of torque.

Results:

[0042] Measurement of torque by both the sensors (T12 and existing torque measurement system) was carried out at various speed and axial thrust (applied by the means of standard weights). Results are provided in the table below.

Sl. No. Shaft Speed (rpm) Axial thrust (kg) Torque measured by Load Cell
(N-m) Torque Measured by T12
(N-m) Error
(%)
1 500 0 448.22 447.567 0.146
2 300 0 417.198 417.682 -0.116
3 300 200 419.585 420.116 -0.126
4 300 400 430.598 431.207 -0.141
5 300 600 422.31 422.758 -0.106
6 150 0 451.03 451.534 -0.112
7 150 200 432.594 431.626 0.224
8 150 400 421.97 422.057 -0.021

Table 1: Torque measurements data (T12 and existing torque measurement system)

[0043] Data represented by red curve is recorded by T12 torque meter and data represented by white curve is recorded by existing torque measurement system using load cell.

[0044] Data represented by red curve is recorded by T12 torque meter and data represented by white curve is recorded by existing torque measurement system using load cell. As seen in the Figure 6 above, for a brief period friction torque transfer system was removed in the existing torque measurement system and again put in place. Therefore there is a dip in white curve for that period, however after putting friction torque transfer system back in place, both curve overlapped.
Conclusions:

[0045] The experimental study was conducted at different shaft speeds and axial loading. As evident from the result given by table and graphs above, torque measured from T12 torque meter and existing torque measurement setup matches very well under each condition. The validation setup thus developed is fulfilling all the requirements. Hence, it is recommended that torque measurement system validation be carried out periodically using this set up and be a part of IEC 60193 as a standard test procedure.

[0046] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases, it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.

[0047] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all groups used in the appended claims.

[0048] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particulars claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogues to “at least one of A, B and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B”.

[0049] The above description does not provide specific details of manufacture or design of the various components. Those of skill in the art are familiar with such details, and unless departures from those techniques are set out, techniques, known, related art or later developed designs and materials should be employed. Those in the art are capable of choosing suitable manufacturing and design details.

[0050] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. It will be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be combined into other systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may subsequently be made by those skilled in the art without departing from the scope of the present disclosure as encompassed by the following claims.

[0051] The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others.

[0052] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.