TECHNICAL SPECIFICATION FOR RTM BLOWERS - RDSO

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GOVERNMENT OF INDIA

MINISTRY OF RAILWAYS

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TECHNICAL SPECIFICATION FOR HIGH CAPACITY FTTM BLOWERS FOR

BROAD GUAGE AC/DC LOCOMOTIVES WITH MODIFIED PTU AND ALTERNATOR

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Specification No.MP- 0.2400.11, (Rev.- 0.02)

FEBRUARY- 2009, (Rev.- 0.03)

NOVEMBER- 2018

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RESEARCH DESIGNS & STANDARDS ORGANISATION

MANAK NAGAR, LUCKNOW - 226011.

RDSO SPECIFICATION NO. MP-0.2400.11 (REV. 0.03), NOVEMBER 2018

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TECHNICAL SPECIFICATION FOR HIGH CAPACITY FTTM BLOWERS FOR BROAD GAUGE AC/DC LOCOMOTIVES FITTED WITH MODIFIED PTU

AND ALTERNATOR MOUNTED RECTIFIER 1. SCOPE

The AC-DC ALCo locomotives have rectifier that is either cooled by air of plenum chamber (FTTM blower air) or cooled by separate motor driven blower. In the recent design, rectifiers are mounted on the top of the alternator and cooled by the alternator fan. In the earlier design where rectifier was cooled by FTTM blower air, the FTTM blower was designed for 12000 CFM air. In the later design (self cooled and alternator mounted rectifier), the FTTM air is not required to cool the rectifier. In these designs capacity of FTMB is being downgraded to 9500 CFM range. This specification covers FTMB of both capacities i.e. 12000 CFM range and 9500 CFM range capacity blowers.

This specification covers the schedule of technical requirement for supply; performance and testing of centrifugal blowers (12000 CFM blowers as well as 9500 CFM blowers) for fitment at the end of power take off unit. Provision of both capacities is being kept so that both the blowers are available for retro fitment on locomotives depending upon rectifier cooling.

This specification will be applicable for all class of locomotives having AC/DC transmission, which are provided with self-cooled rectifier, alternator mounted rectifier or fitted with FTTMB cooled rectifier. The general arrangement for cooling rectifier through a plenum chamber in the locomotive from the blower is shown in the attached sketch-I.

The blower shall be of double width double inlet type centrifugal blower. Relatively open inlet conditions on one end and the presence of PTU on the other side shall be taken into consideration while designing the impeller. The impeller of the blower shall be forward curved welded design.

Railways shall decide on the type of the blower to be procured depending upon the cooling arrangement of the rectifier as detailed above.

2. TERMINOLOGY, SYMBOLS & UNITS Terminology, symbols and units used in design and manufacture of the blower and its related components shall be as per BS: 848-1980 'Specification for Fans for general purposes. 3. SERVICE CONDITION

3.1 Ambient temperature of air at inlet to the blower 5 deg. to 60 deg. Centigrade. Humidity ranging up to 100% saturation. Maximum altitude 1000 m above sea level.

3.2 The equipment shall be robust design for traction duty and shall withstand satisfactorily the vibrations and shocks normally encountered in service as indicated below: a) Maximum vertical acceleration 1.0 g b) Maximum longitudinal acceleration 3.0 g due to shock. c) Maximum transverse acceleration 0 .5 g


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3.3 Sine wave vibrations are encountered with frequency between 1 Hz & 50 Hz. The amplitude ‘a’ expressed in millimeters is given as a function of f by the equation

amplitude q= 25/f, f between 1 Hz & 10 Hz q = 250/f² between 10 Hz & 50 Hz

4. DIMENSIONS AND MOUNTING

4.1 The blower supplies air to the front traction motors through a plenum chamber

in the locomotive under frame. The discharge of the blower is connected to cut out in plenum chamber.

4.2 The blower covered by this specification is for use on WDM3C, WDG3A & WDP3A class AC/DC locomotives. The drive for the blower is obtained from the alternator gear train of 102/43 gear ratios. The 43 teeth pinion drives a PTU shaft supported on bearings in the PTU casing. The impeller hub of the blower is mounted directly on this shaft end. The maximum rpm of PTU shaft is 2490. The blower offered by the manufacturer shall be such that –

a) It has a matching taper bore on the impeller hub for mounting on the PTU shaft. Refer drawing no SK.DP-3103

b) It should meet diametrical limitations imposed by other 2 auxiliary machines mounted on the alternator gear case. The outside dimension of the casing shall be such as to allow its fitment with Power take off unit without infringing with the aux. gen. and exciter frames.

4.3 The direction of rotation looking from drive side is anticlockwise down blast.

4.4 (A) The outline dimensions of the blower shall generally confirm to DLW drawing no. TPL-5328 sheet 1 of 2 for 12,000 CFM FTTM blower.

(B) The outline dimensions of the blower shall generally confirm to RDSO

drawing no. SKDP- 3917 for 9500 CFM FTTM Blower.

4.5 Hub for FTMB will remain same for both type of blowers (9500 CFM and 12000 CFM FTTM blowers) and shall generally confirm to DLW drawing no.SK. No. 2028 (part no. 11457340).

4.6 Details of drawings of both types of blowers are as following: -

Type Description Drawing No. Applicable for

Type 1 12,000 CFM FTTM Blower

DLW drawing no. TPL-5328

Performance curve-GDP-1025

AC-DC locomotives fitted with FTTM air cooled rectifier

Type 2 9500 CFM FTTM Blower.

RDSO drawing No. SK.DP-3917

Performance curve-GDP-1176

AC-DC locomotives fitted with alternator mounted rectifier or with self cooled rectifier with in built blower

4.7 Mounting dimensions and locations of holes are essentials for

interchangeability of blowers from one manufacturer to other manufacturer. Overall casing dimensions as shown in drawing shall not to be exceeded. In


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case of alternate design, the firm should submit complete details & the drawings for the approval of RDSO.

5. MATERIALS 5.1 The blower and its related components shall be made of suitable steel

conforming to relevant standards as per requirement given below:

a) Casing: Casing shall be fabricated of mild steel conforming to IS: 2062, Grade ‘B’. The thickness of side plates and scroll shall be minimum 3 mm and 2 mm respectively.

b) Impeller: The impeller of the blower shall be fabricated and made of high tensile steel conforming to IS 2062 grade ‘B’. The thickness of back plate and blade shall be 3.2 mm and 1.8 mm minimum respectively. Impeller blade shall be welded with base plate with proper sequence to avoid distortion and undue stress developed due to welding.

Good welding techniques like CO2 welding or low hydrogen electrode with DC welding machine shall be employed for fabricating the impeller. Care shall be taken to avoid under cut and other welding defects to the impeller. For this purpose, arc shall be manipulated properly by directing towards the base plate. Dye penetration test shall be carried out after cleaning the welds to ensure freedom from surface defects. Impeller shall be subjected to stress relieving treatment at 650 deg. centigrade for 40 to 45 minutes followed by slow cooling. After stress relieving the impeller shall be inspected visually for development of any crack and dimensional check shall be carried out for any unwanted distortion.

c) Hardware: All fasteners used shall be made of high tensile class of steel Gr. 8.8. The fasteners to be tightened with required torque recommended by the manufacturer.

d) The impeller and casing shall be suitably treated to remove rust and should be coated with an anti- rust primer and finished with steel gray paint.

5.2 The manufacturer can use a superior material for the above items subject to

prior approval by the purchaser. 6. DESIGN AND GENERAL GUIDELINES 6.1 Strip edge of the impeller blades shall be properly grounded and ensuring no

burrs and other defects to match with the base plate. 6.2 All welds and standards shall be as per ASME section VIII. 6.3 Welding is to be done by qualified welders. 6.4 Dye penetration test to be done at all critical locations like impeller etc. 6.5 Casing scroll shall be designed to withstand impeller disintegration at 125% of

rated speed. 6.6 The blower impeller shall be statically and dynamically balanced as per ISO:

1940 Grade Q 6.3.


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6.7 All fan assemblies shall be sand blasted and painted with steel gray colour and minimum DFT of the paints will be in between 60 to 80 microns.

6.8 These blowers shall operate for extended periods on high speeds. Therefore

the impeller blades have to be designed with higher margins of safety as compared to standard industrial design.

6.9 The maximum clearance between inlet cone and impeller shall be 6 mm. 6.10 Provision of aerodynamically profiled guards shall be preferred to prevent

accidental contact with rotating impeller and at the same time not restricting the inlet of air into blower substantially.

6.11 An arrow indicating the direction of rotation shall be permanently marked on

the blower casing. 6.12 Suitable lifting arrangement for the blower casing shall be provided 6.13 Stainless steel nameplates shall be provided. 6.14 Manufacturer has to furnish the blower details like blade angle, curvature

details, impeller hub base diameter etc before conducting the type test. 7 (A). PERFORMANCE DATA & CHARACTERISTICS (for 12000 CFM capacity

FTTM blowers)

I. The blower characteristics shall generally match the curve given in RDSO graph no. GDP-1025 at 2490 rpm.

II. The blower shall be capable of delivering 12000 CFM (+2.5%) at 8.5 inch of WG at blower outlet in reference site conditions of 21 deg. centigrade and 29.92 inch of Hg of atmospheric pressure at 2490 rpm of PTU shaft.

III. The blower shall not consume more than 50 HP at 2490 rpm at the point of rating of 8.5 inch of WG static pressure.

IV. The fan total efficiency shall not be less than 50 % at duty point. 7 (B). PERFORMANCE DATA & CHARACTERISTICS (for 9500 CFM capacity

FTTM blowers)

I. The blower characteristics shall generally match the curve given in RDSO graph no. GDP-1176 at 2490 rpm.

II. The blower shall be capable of delivering 9500 CFM (+2.5%) at 8.5 inch of WG at blower outlet in reference site conditions of 21 deg. centigrade and 29.92 inch of Hg of atmospheric pressure at 2490 rpm of PTU shaft.

III. The blower shall not consume more than 42 HP at 2490 rpm at the point of rating of 8.5 inch of WG static pressure.

IV. The fan total efficiency shall not be less than 50% at duty point. 8. TYPE TESTS 8.1 The blower shall be type tested at the manufacturer's premises for its air

delivery, static pressure and power consumption in accordance with BS: 848-1980. Following type tests shall be carried out in the presence of the representatives of RDSO and the purchaser.


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a) Visual examination: The blower shall be examined for workmanship and other provisions of this specification.

b) Dimensional check: The verification of blower dimensions and clearances

with respect to mounting/space requirements and the assembly drawing submitted by the manufacturer shall be checked.

c) Air delivery test: It shall be carried out as per BS: 848. A suitable test drive

motor with coupling arrangement identical to PTU shaft/blower impeller shall be provided.

d) Starting Duty test: The blower shall be subjected to repeated start and stop

cycling for 1000 times at 20% of rated RPM. The on & off period shall be one minute in each case. If unit takes more than one minute to stop freely the next start shall commence immediately after the unit has stopped. At the end of the test the efficiency of impeller locking on tapered shaft shall be checked. The impeller shall be dismantled and examined for damage or abnormal wear.

e) Checks on welds of impeller and housing: A suitable method

commensurate with the welding technique and grade employed shall be used to make checks on soundness of welds.

f) Over speed test: The blower shall be run at 20 percent over the rated full load

speed for a period of one hour against rated air delivery. After the run, the impeller shall be examined for any damage.

g) Endurance test: This test shall be conducted for a period of fifty hours with

rated volume flow, and RPM. After the test the blower shall be dismantled and examined for wear and tear of the parts and deterioration/degradation of components.

h) Vibration test: The blower shall also be tested for vibrations as per ISO 2372

in horizontal, vertical, and axial planes on the blower casing which shall not exceed 75 microns on rated speed and duty.

i) Dye penetration test: This test shall be conducted on the impeller after

endurance test to ensure that there is no crack formation on the impeller. 8.2 After the above tests, if it is felt by RDSO/ purchaser to repeat the tests or

carry out some more tests on the prototypes, the same shall be arranged by the manufacturer at their own cost.

8.3 The above tests may, at the discretion of the purchaser, be reduced in scope

in case of blowers proved under local conditions of service. 8.4 Type tests shall normally be carried out before execution of the first

development order or every three five years subsequently. In addition, RDSO may require to conduct fresh type test, should a need arise based on performance feed back.

9. SERVICE TRIALS 9.1 The manufacturer seeking for approval will supply two prototypes to the

purchaser, after successful type testing for their correct fitment on broad


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gauge AC/DC locomotives. Any modification if required on the blower shall be checked up and carried out by the manufacturer.

9.2 These blowers will be subjected to extensive service trials for a period of 12

months or more as deemed necessary by the RDSO and the purchaser to prove the design, equipment performance, maintainability and reliability. All modifications found necessary based on the service trials to improve upon the blower design and physical construction and as mutually agreed shall be incorporated in the prototypes and in the series supplies of the equipment, at the cost of the supplier and in the manner approved by the purchaser.

9.3 The detailed scheme of prototype trials to satisfy the above shall be indicated by the supplier and mutually finalised in consultation with the purchaser. Special instrumentation, if any, for correct appreciation of the various data will have to be arranged by the tenderer.

9.4 The prototypes shall be cleared in both type tests and service trials before

granting approval to the manufacturer. 9.5 Series production shall be started only after successful type tests and field

trials. 10. MARKING The blower shall be indelibly marked with at least the following on stainless steel sheet:

a) Manufacturer's name, trade name of fan (if any) and Serial No/Date of manufacture.

b) Rated speed of fan in rev/min.

c) Direction of rotation and direction of airflow

d) Air delivery at stated duty

e) Fan total efficiency

f) Size of impeller

g) Number of blades

h) Power consumption at stated duty 11. PACKING

The blower and its related components shall be packed as to permit convenient handling and to protect against loss or damage during transit and storage.

12. TECHNICAL PARTICULARS TO BE FURNISHED BY THE SUPPLIER 12.1 A complete set of detailed drawings of blower and its related component

showing overall dimensions and material etc. shall be submitted to RDSO and the purchaser for prior approval and for the purpose of carrying out inspection.

12.2 The supplier shall submit the following characteristic curves at 21 deg.

centigrade & 29.92 inches of Hg of atmospheric pressure at rated rpm:

a) Total & Static pressure vs. Air delivery.


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b) Horsepower consumption vs. Air delivery. c) Total & static Efficiency vs. Air delivery.

12.3 The supplier shall also furnish the following characteristic curves at 21 deg.

centigrade & 29.92 inches of Hg of atmospheric pressure for 3100 HP & 3300 HP diesel-electric locomotives:

a) Total & static pressure vs Air delivery (notch wise).

b) Power consumption vs Air delivery (notch wise )

Notch wise engine RPM and blower RPM of the 3100 HP & 3300 HP diesel electric locomotives are as under:

Notch position

Idle 1st 2nd 3rd 4th 5th 6th 7th 8th

Engine RPM

400 400 493 586 679 772 865 958 1050

Blower RPM

949 949 1170 1390 1610 1832 2052 2272 2490

12.4 Full calculation in support of the design capacity of the blower offered. 12.5 Detailed Marking scheme on each individual blower. 13. DEVIATION STATEMENT The supplier shall submit item wise deviation statement seeking approval for marking deviation from the above drawings and specification. In case no relaxation is sought, 'NIL' statement shall be submitted. 14. QUALITY ASSURANCE PROGRAMME (QAP) The supplier shall submit his internal quality assurance plan to RDSO and the purchaser. In the said QAP, infrastructure facilities (comprising of testing and manufacturing facilities), frequency of various checks, details of nature of work involved in the checks and record maintained regarding these checks should be indicated. The supplier shall, on demand by RDSO or the purchaser or the Inspecting authority nominated by the purchaser, make the records of checks carried out during internal quality assurance available for scrutiny. 15. MAINTENANCE The supplier shall supply free copies of the approved maintenance manual for running and overhaul running maintenance purpose at the rate of ten copies per purchase order. In situ checks: Either based on 30 days, 120 days, 240 days or 360 days Overhaul: Either based on 24 months or its multiple. 16. COLOUR The blower shall be supplied in steel gray colour unless otherwise stated in the purchase order. Quality of paint shall be as per relevant I.S. publication, the details of which shall be indicated.


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17. WARRANTY The blower shall be warranted for satisfactory and trouble free operation for a period of 3 years from the date of receipt or 2 years from the date commissioning in service whichever is earlier. 18. ACCEPTANCE

The acceptance test of the blower shall constitute the following on the sample basis.

S.No Parameter Quantity checked

1 Visual Examination

100%

2 Dimensional Check

100%, conforming to relevant drawing and manufacture’s components drawings.

3 Air Delivery test Conforming to para-8.1(c), 1 no. or 10% of the lot whichever is higher

4 Over speed Test Conforming to para –8.1(f), 1 no. or 10% of the lot whichever is higher

5 Vibration test Conforming to para-8.1 (h), 2 no. or 20% of the lot whichever is higher

8 Dye Penetration test

1 no. or 5% of the lot whichever is higher. This test shall be carried out after over speed test to ensure that there is no crack formation on impeller and casing

19. TEST CERTIFICATE Three copies of test certificates shall be supplied unless otherwise stated in the purchase order.


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TECHNICAL SPECIFICATION FOR RTM BLOWERS - RDSO

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