Apr 24, 2012 ... shall be of aluminum alloy LM-6. .... Electrolytic capacitors shall be rated for
maximum ... The resistors shall be preferably made of metal film.
Reasoned documents of Comments received from Firms Clause No. 2.1
As per Draft Specification no. RDSO/PE/SPEC/ AC/00212005 (Rev.2) uploaded on website
RDSO’s comments / Modified clause incorporating MOM dated 24.04.2012 RDSO’s comments This specification covers the requirements of design, M/S R.Kanwar manufacture, testing and supply of 400mm sweep BLDC The fan size has been mentioned ac deleted railway carriage fans for rolling stock application complete in as 400 mm sweep, where as it should be 400 mm & 450 mm Modified clause This all respect suitable for input voltage of 110V ac/dc system. sweep both. specification covers the of design, Moreover the Input Voltage has requirements been mentioned as 110V ac/dc, manufacture, testing and supply we expect that since these are of 400mm sweep BLDC railway BLDC Fans and whole of the carriage fans for rolling stock specification including application complete in all performance & testing etc. are respect suitable for input voltage based specifically for DC Supply of 110V dc system. only.
Electronic controller card shall be used as power devices in the inverter. The inverter shall have DSP based control and protections with a single controller board for power supply, protection; sinusoidal generation etc. and gate driver card shall be provided closer to the power devices. The detailed specification for DSP and power devices used shall be given/ submitted before offering for witnessing the prototype testing.
M/S LEC -M/S R.Kanwar The requirement of “DSP based control and protection with a single controller board for power supply etc. and gate driver card shall be provided closer to the power devices”, which may kindly be deleted and left to the developer for adopting any technology. M/S LEC The same function can be achieved by general purpose microcontroller or dedicated ASIC. Then why shall we stick to
RDSO’s comments To open specification for other type of technologies, DSP is accepted for deletion. Modified clause Electronic controller card shall be used as power devices in the inverter. The inverter shall have control and protections with a single controller board for power supply, protection; sinusoidal generation etc. and gate driver card shall be provided closer to the power devices. The detailed specification for power devices used shall be given/ submitted
Input to the unit will be fed through battery bank of 110V dc in parallel with alternator, rectifier cum regulator. The unit shall be suitable for operating voltage available as input i.e. 90V to 140V DC with 15% ripple. The over voltage trip shall be set at 155V
DSP based system only? DSP is used for high end data processing and it is underutilization of resources if we are using it for this application. M/S R.Kanwar Over Voltage trip has been mentioned as 155V, it will be better if this is modify to 150V ± 2%. M/S LEC Over Voltage trip shall be set at 155 V. Acc. To our view there should be tolerance of +/- 5V due to inherent tolerance value of components.
M/S R.Kanwar For Long Life and minimum & negligible damage to the aluminum motor body and cover (for mounting PCB), the minimum thickness may kindly be specified as 4 mm ± 0.1 mm. This is to avoid any breakage etc. of the Aluminum Motor Body mainly at the time of replacement of the bearings & maintenance etc. It is surprising that in the last of PCD : 108 mm this clause your Honour has No. of holes : 3 at equal distance permitted for the extension of the Hole diameter : 9 mm Fan Body color for fixing of the For fixing of fan guard, extension of fan body collor or Fan Guard, which will clearly be the deviation to the RDSO provision of additional collor shall be used. Drg. Of Deep Drawn Design
The motor of the fan shall be permanent magnet type, light in weight and small in size without field winding, brushes and commutator. The stator may be of two or more windings. The permanent magnet shall be fitted on the rotor in such a manner that it should not get disengaged. It is desirable that the magnet shall be embedded in slots. Deep drawn design for fan body made from MS sheet shall conform to RDSO drg. No. RDSO/PE/SK/TL/0025-2002 (Rev.0) Motor body shall be of aluminum alloy LM-6. Details of mounting of fan to coach ceiling are as under.
before offering for witnessing the prototype testing.
RDSO’s comments To provide some tolerance, over voltage trip shall be set between 150 to 155V is considered. Modified clause Input to the unit will be fed through battery bank of 110V dc in parallel with alternator, rectifier cum regulator. The unit shall be suitable for operating voltage available as input i.e. 90V to 140V DC with 15% ripple. The over voltage trip shall be set between 150 to 155V. RDSO’s comments For interchangeability and easy migration of DC fan manufacturer to BLDC, fan body needs to be same as that of DC/AC fan and should be as per RDSO drawing no. RDSO/ PE/SK/TL/0025-2002 (Rev.0). Most of the existing vendors of BLDC fan are also using same fan body as per RDSO drawing. Modified clause For fixing of fan guard, separate provision of collor or extension of fan motor body may be provided.
Fan Body. However for Long Life the separate Aluminum additional color shall be attached / provided with Fan Motor body with “M8, 20 mm” long screw. M/S LEC LEC is using deep drawn design for body made of MS sheet as per RDSO drg. RDSO/PE/SK/ TL/0025-2002(Rev 0) as per RDSO requirement & the fan body design is same as used in conventional fans. So no additional collar is required. PROPERTIES FOR PERMANENT MAGNET: M/S R.Kanwar RDSO’s comments Sr. No. ‘4’, it may kindly be • Clause No. corrected as ‘8.7’ The permanent magnet to be used on the fan shall modify to Clause No. ‘8.7’ • Based on the discussion instead of ‘8.6’. have the following properties: during meeting,1300-2000 Gauss is considered for rotor • Value of coercive force shall be advised after The Gauss Value may kindly be magnet amended as 1600 – 2000 for Modified clause designing the fan • Hardness of the magnet shall not exceed 700 HV better performance. The permanent magnet to be used on the fan shall have the • It shall have smooth ground surface. following properties: • It shall meet the requirement of clause 8.6 of this M/S LEC -• Value of coercive force shall specification. be advised after designing the • Rotor magnet shall have 1600-1800 Gauss. fan • Hardness of the magnet shall not exceed 700 HV • It shall have smooth ground surface. • It shall meet the requirement of clause 8.7 of this specification. • Rotor magnet shall have 13002000 Gauss.
M/S R.Kanwar so far been in India to the best of Fan blades shall conform to RDSO drg. No. our knowledge there are only 2 RDSO/PE/SK/TL/0108-2008 (ALT ‘1’) (Rev.0) and shall be firms who are manufacturing easily replaceable / interchangeable. these FRP blades which are :(1) M/s Paras Agro Plast (Pvt.) Ltd., Gujarat:- Who is The blade shall be made of fire retardant plastic material manufacturing the FRP meeting the following requirements:Blades as per RDSO Drg. No. RDSO/PE/SK/TL/0108§ Melting point ASTM D 2177 218°C minimum 2008 (Alt. ‘1’) Rev ‘0’. § Heat deflection temperature under (2) M/s Qumex, Kolkata: - Who load at 1.82 MPa ASTM D648. 180°C minimum is manufacturing the FRP § Flammability UL 94 – VO Blades as per RDSO Drg. § Tensile strength ASTM D638 MPa 90MPa minimum No. RDSO/PE/SK/TL/0108§ Flexural strength ASTM D790 MPa 130 MPa minimum 2008 (Alt. ‘0’) Rev ‘0’. § Elongation at breaks ASTM D 638 4 - 6% The blades so far provided by § Impact strength ASTM D 256 A 6.0 kg.-cm/cm minimum us in our BLDC Fans are as § Rockwell hardness ASTM D 785 120 R Scale minimum per Alt. ‘0’ and there is no any § Glass filling 30% complaint and the performance is also much satisfactory. Please review the same before finalizing the FRP Blade Drg. Sir, keeping in view the difference in the properties mentioned in the spec. and Drg. The same may kindly be deleted from the said draft spec. and shall be applicable as per the RDSO Drg. No. RDSO/PE/SK/TL/0108-2008 (Alt. ‘0’), Rev ‘0’. M/S LEC ---
RDSO’s comments Latest RDSO drg. No. RDSO/ PE/SK/TL/0108-2008 (ALT ‘1’) (Rev.0) is to be referred. Modified clause Fan blades shall conform to RDSO drg. No. RDSO/PE/ SK/ TL/0108-2008 (ALT ‘1’) (Rev.0) and shall be easily replaceable / interchangeable.
ELECTRONIC CONTROLLER: Electronic components used in electronic controller or elsewhere in fans shall be as under: i. ii. iii. iv. v. vi.
vii. viii. ix.
M/S R.Kanwar Sr. No. “IX” : The Three Phase Output Voltage has been mentioned as “54V”, which may kindly be modify to “Approx. 54V” due to the reason that the No. of turns of the stator are also varying from 435 to 480 turns and variation in the tolerance in the Electronic Components specifically in resistances etc.
RDSO’s comments To provide tolerance, 54V±2 volts with provision of 6 nos. mounting holes as per RDSO drawing no. RDSO/PE/ SK/TL/ 0153-2011 (Rev ‘0’) - sheet 1 of 4 is considered. Modified clause iv. Hall Effect sensor (if used) shall be rated for 65°C ambient and shall conform to RDSO/PE/SK/TL/0153-2011 Secondly, when the Drg. Of the (Rev ‘0’) - sheet 4 of 4. PCB has been attached with the spec. as such the mentioning of ix. The controller card shall be “provision of 6 Nos. of mounting used with three phase output holes at 120°” is not required. voltage of 54V±2 volts with The comments to this Drg. Has provision of 6 nos. mounting already been submitted by us holes as per RDSO drawing no. vide our Letter No.: RDSO/PE/SK/TL/0153-2011 RKE/RDSO/BLDC, Dtd.: 15-04- (Rev ‘0’) - sheet 1 of 4. 2011.
IC (Integrated Circuits) shall be of Industrial Grade. Electrolytic capacitors shall be rated for maximum temperature of 105°C (Mill grade/ Industrial grade.) Paper/polyester capacitors shall be rated for maximum temperature of 85°C No Hall Effect sensor shall be used for sensing the rotor position. The resistors shall be preferably made of metal film of adequate rating. Switching devices such as transistors, MOSFETs and IGBTs shall have minimum junction temperature of 150°C. Devices shall have 20°C thermal margin at the ambient of 55°C Material for printed circuit board shall be copper clad glass epoxy of grade FR-4 or superior. The controller card shall be used with three phase output voltage of 54V with provision of 6 nos. M/S LEC mounting holes at 1200. ---
The connector shall be provided as per RDSO drawing no. RDSO/PE/SK/TL/0153-2011 (Rev ‘0’) - sheet 3 of 3 and in such a manner that looking from top of the connector from left side pin, configuration shall be R, Y, B at the output.
M/S R.Kanwar RDSO’s comments We hereby agree for the Not agreed. provision of the connector as per MAKE mentioned in the said Specification, however the place / position will be determined while finalizing & R&D. M/S LEC ---
STATOR Stator used in BLDC fans shall be as under: No. of poles No. of slots No. of turns Stack length Stack outer dia Stack inner dia
:3 :6 : 435-480 : 11.5 ±o.5 : 87 mm : 56.2 ±0.2
ROTOR AND ROTOR MAGNET:
M/S R.Kanwar Instead of mentioning the “No. of Poles” we expect that it shall be “No. of Phase”. M/S LEC No. of poles should be read as No. of phase: 3.
M/S R.Kanwar This is the matter of R&D and my Rotor and rotor magnet used in BLDC fans shall be be decided / finalize after as per RDSO drawing no. RDSO/PE/SK/ TL/0153- successfully development of the 2011 (Rev ‘0’) – sheet 1 of 3 and sheet 2 0f 3 Sensor Less BLDC Fan. respectively. However the comments / observation for RDSO Drg. No.: RDSO/PE/SK/TL/0153-2011 (Rev. ‘0’) – sheet 1 of 3, 2 of 3 and 3 of 3 has already been submitted by us vide our Letter No.: RKE/RDSO/BLDC, Dtd. 15-04-2011, the same may kindly be linked. And following facts may kindly be also considered :1) From your Rotor Magnet Drg. the thickness of the Magnet comes out to 3 mm, however for longer life & to minimize of the breakage / cracks etc. during maintenance the same may kindly be modified to OD – 55 mm & ID – 46 mm.
RDSO’s comments No. of Pole is changed as no. of phase Modified clause STATOR Stator used in BLDC fans shall be as under: No. of phase :3 No. of slots :6 No. of turns : 435-480 Stack length : 11.5 ±o.5 Stack outer dia : 87 mm Stack inner dia : 56.2 ±0.2 RDSO’s comments 4-pole rotor magnet is added Modified clause 4-pole rotor magnet and shaft used in BLDC fans shall be as per RDSO drawing no. RDSO/PE/SK/ TL/0153-2011 (Rev ‘0’) – sheet 2 of 4 and sheet 3 of 4 respectively.
2) The Stator Stack Length (Cl. No. 4.6) has been mentioned as 11.5 ± 0.5 mm, where as in your Rotor Magnet Drg. the Width of the magnet has been indicated as 11.0 ± 0.15 mm, which is contradictory, as such the same may be kept as 11.5 ± 0.5 mm. Note :- The above modified dimensions were earlier adopted by M/s CGL also. M/S LEC In RDSO drg no. RDSO/PE/SK/TL/0153-2011 (Rev ‘0’) Sheet 2 of 3 Inner Diameter is mentioned (49.00 +0.20, +0.05). Kindly clarify the tolerances. BEARINGS: M/S R.Kanwar In Indian Railways all the 110 V SKF make (6201ZZ) ball bearings or equivalent in NBC/ FAG DC / AC, 400 mm sweep R.C make bearing shall be used. Fans are being provided with 6200 bearings, inspite of the fact that the weight of the Armature is approx. 1 Kg and the weight of the Mild Steel Blade is approx. 700 gms. Instead of existing FRP Blade & Rotor of about 650 gms. Provided in these BLDC Fans. Using of 6200 bearings will also helps in Wattage Reduction. The said 6200 bearing has already been recommended by your Honour in IS : 6680/1992 Cl. No.: 8.6 along with dimensions from the date these fans were
RDSO’s comments As most of the existing BLDC fan manufacturers are using 6201zz bearings, it has been accepted from standardisation point of view.
COLOUR OF FAN BLADE AND BODY: Complete fan i.e. fan body, motor body, fan guard assembly (of mild steel) etc. shall be powder coated with minimum thickness of 60 microns to colour silver metallic finish to HVC 100 of HAWCOPLAST / 95-03014 of MARPOL. A band of dark yellow colour of about 20 mm wide over the periphery of the fan body approximately at its middle portion shall be applied as a colour code for the fan.
GUARD: Crashworthy design of fan guard shall conform to ICF drg No. ICF/SK-7-6-158 alt. ‘C’
developed in India. As such your Honour is requested to kindly modify the same as “6200ZZ having L10 life” instead of “6201ZZ”. M/S LEC -M/S R.Kanwar Presently the BLDC Fans are provided with a bank of dark Yellow colour, we recommend that in Sensor Less BLDC Fans it shall be changed to “Red Colour” for easy identification of the Sensor Less BLDC Fans.
RDSO’s comments Based on the discussion during meeting and to identify new design BLDC fan, green is added Modified clause Complete fan i.e. fan body, motor body, fan guard assembly (of mild steel) etc. shall be powder coated with minimum thickness M/S LEC of 60 microns to colour silver Color shade to be read as HYC metallic finish to HVC 100 of 100 of Hawcoplast. HAWCOPLAST / 95-03014 of MARPOL. A band of colour of about 20 mm wide over the periphery of the fan body approximately at its middle portion shall be applied as a colour code for the following • Dark green :BLDC fan without Hall sensor • Dark yellow :BLDC fan with Hall sensor M/S R.Kanwar RDSO’s comments Alt. “C” may kindly be replaced Latest ICF drg No. is corrected with “”Alt. “D” Coll – II””. as ICF/SK-7-6-158 alt. ‘D’ coll-II. M/S LEC Modified clause Crashworthy Design of fan guard Crashworthy design of fan guard shall conform to ICF drg No. shall conform to ICF drg No. ICF/SK-7-6-158 alt ‘d’ COL-II. ICF/SK-7-6-158 alt. ‘D’ coll-II.
The fan shall be light weight and energy efficient with maximum air delivery at rated voltage. The details specified against each size of fan are given in Table 1.
Minimum air delivery in cubic meter per minute Max. input power in watt Maximum weight in Kg Min. service value in cub Noise level (maximum)
Table 1 Performance Data Fan Size 400 mm sweep
450 mm sweep
32 7 2 55 dBA
35 8.5 2 60 dBA
The following type, routine and acceptance tests shall be M/S R.Kanwar conducted on Brushless DC Railway Carriage Fans.(SN.13) The request / comments and observations for Type, Routine & Acceptance Teats may kindly be reviewed for practicable aspects as under please :Sr. No. (1) to (16) – all are acceptable except Sr. No. (13) AD Test, which has been added in Routine & Acceptance Tests both, the reason for the same is given against Cl. No. 8.13. M/S LEC --
RDSO’s comments As only 400mm sweep BLDC fan has been developed so far, Details of 450mm sweep fan is deleted Modified clause The fan shall be light weight and energy efficient with maximum air delivery at rated voltage and shall conform to following parameters: a. Minimum air delivery in cubic meter per minute :60 b. Max. input power in watt :32 c. Maximum weight in Kilograms :7 d Min. service value in cub meter /min/watt :2 e. Noise level (maximum) :55 dBA RDSO’s comments Based on the discussion during meeting,500th fan is indicated in place of Y in routine test at Sr. No. (13) Modified clause Air delivery test on every 500th fan during routine test is indicated in place of every fan
STARTING TEST: The fan shall be capable of starting from rest at ≤65 volts.
M/S R.Kanwar This Clause is contradictory to Cl. No. 8.6.2 of the said spec., because as per this Cl. No. 8.3 the Fan should be start at ≤ 65 volts and as per Cl. No. 8.6.2 the Fan should be tripped when the input voltage is less then 65V and shall be restart automatically whenever the voltage is above 70V.
RDSO’s comments To avoid frequent start and stop of BLDC fan due to battery voltage fluctuation, ≤75 volts is considered in place of ≤65 volts Modified clause The fan shall be capable of starting from rest at ≤75 volts
As such your Honour is requested to kindly modify the starting voltage as ≤ 70 volts instead of ≤ 65 volts & restarting voltage 75 V instead of 70V. M/S LEC The tolerance of 5v should allowed due to inherent tolerance value of components. 8.5
ELECTRICAL INPUT TEST:
The electrical input in watts to the fan shall be determined by The Electrical Input Test shall be the running the fan at rated voltage. However input watts at applicable at Rated Voltage i.e. other voltages i.e. 90, 100, 120, 130 and 140 V shall also be 110 VDC for Routine & recorded for reference purpose. Acceptance Tests, where as this testing for reference purposes of Input Watts at other voltage i.e. 90, 100, 120, 130 & 140 VDC shall be applicable for Type Tests only. As such the same may kindly be mentioned in the spec. clearly.
RDSO’s comments As these tests are required to be done only during prototype test, ‘During prototype test’ is added at the last. Modified clause The electrical input in watts to the fan shall be determined by the running the fan at rated voltage. However input watts at other voltages i.e. 90, 100, 120, 130 and 140 V shall also be recorded
Input over voltage protection shall be provided in the circuit so that whenever input voltage increased beyond 155V, the fan shall trip and whenever the voltage comes down to 140V, the fan shall start automatically.
Input under voltage protection shall be provided in the circuit so that whenever input voltage decreased below 65V, the fan shall trip and whenever the voltage comes above, the fan shall start automatically. Capability to withstand input of 200V DC without any damage to any part of the BLDC fan for two minute shall also be provided.
M/S LEC Electrical Input in watts at rated voltage only should be in routine & acceptance tests. However RDSO during Type test can record input watts at other voltages. M/S R.Kanwar The OVP shall be provided at 150 VDC ± 2% and shall be restart automatically whenever the voltage comes down to 145 VDC ± 2%. M/S LEC There should be a tolerance of +/- 5V due to inherent tolerance value of the components. M/S R.Kanwar
for reference prototype test.
RDSO’s comments No change
This is contradictory to Cl. No. • 70V (5V Hysteresis) is 8.3 above, according to this changed as 75V (10V Clause the fan should start at ≤ Hysteresis) in line with clause 65 Volts, where as the said 65V no.8.3.. is decreased the fan should be • ‘based on the discussion tripped. during meeting,This shall be tested for 30 minutes during As such this may also be type test and for 2 minutes modified that the fan should during routine and acceptance tripped whenever the Input test’ is added in the last. Voltage decreased below 70V & shall restart whenever the Modified clause voltage comes above 75V. Input under voltage protection M/S LEC shall be provided in the circuit so There should be a tolerance of that whenever input voltage +/- 5V due to inherent tolerance decreases below 65V, the fan value of the components shall trip and whenever the
voltage comes to 75V ( 10V Hysteresis), the fan shall start automatically. Capability to withstand input of 200V DC without any damage to any part of the BLDC fan for 30 minute shall also be provided. This shall be tested for 30 minutes during type test and for 2 minutes during routine and acceptance test. 8.9
LOCKED ROTOR TEST: This test shall be conducted after heating test of the magnet and reverse polarity test. The fans shall be subjected to the highest value of the voltage range i.e. 140V for one hour with the armature in the locked conditions providing external means to arrest the rotation of fan. The fan under this condition shall draw no appreciable current. After the removal of the lock condition, the fan shall start automatically or switching OFF and ON the power supply.
M/S R.Kanwar No Comments. M/S LEC In Acceptance test, It should done on one fan only and power input & air delivery tested shall be repeated in accordance to clause 8.5 & 8.13 respectively..
Thereafter, the performance test i.e Power input and air delivery tests shall be repeated in accordance with Clause 8.5 & 8.12 respectively. There shall be no appreciable variation from initial performance test values. 8.10
TEMPERATURE RISE TEST: sl. no. of the table
RDSO’s comments Based on the discussion during meeting, Note added as ‘During acceptance test, air-delivery test shall be conducted on one fan before locked rotor test and on all the fans (sampled) after locked rotor test’. Modified clause Note: During acceptance test, air-delivery test shall be conducted on one fan before locked rotor test and on all the fans (sampled) after locked rotor test.
M/S R.Kanwar RDSO’s comments In Temp. Rise Test “Table” there sl. no. of the table corrected is some typographically error, the same may kindly be reviewed. M/S LEC --
AIR DELIVERY TEST:
This test shall be conducted as per Clause No.19.2 of IS: We expect that the AD Test 6680. It is desirable that air delivery shall not be varied in the during Routine Testing means on voltage range from 90V to 110V. each & every fan, where as this has already been included in the Acceptance Test also, we expect that this can be deleted both from the Routine & Acceptance Tests. If the following facts are considered. This testing may kindly be based on the RPM & Input Wattage of the fan i.e. when the RPM of the fan under testing is more the RPM and Input Wattage is either same or less of the fan specified during Type Testing. Accordingly the minimum RPM and Input Wattage may kindly be specifically be mentioned / specified during Type Testing for AD Test. M/S LEC Air Delivery Test: It is mentioned that air delivery shall not be varied in voltage range from 90V to 110V. According to LEC the Air delivery will vary within the voltage range. Air delivery shall be checked at the rated voltage only at 110V.
RDSO’s comments Based on discussion, Clause amended Modified clause This test shall be conducted as per Clause No.19.2 of IS: 6680. This test shall be conducted at 90 volts, 110 volts and at 140 volts during prototype test. In any case, air-delivery shall not be less than 5% of air-delivery at rated voltage.
SAMPLING PLAN FOR ACCEPTANCE TEST:
M/S R.Kanwar The sampling plan as per Method for sampling of fans for conducting acceptance tests Annexure ‘D’ Table ‘3’ (Cl. shall be as per Annexure D Table 3 (Clause 22.214.171.124) of IS: 126.96.36.199) of IS:6680/92 does not 6680. seems to be practicable for Acceptance Tests, your Honour is therefore requested to kindly review the same as under please Lot Size (in Sample Qty. (in Nos.) Nos.) 1 – 100 02 101 – 500 04 Above 500 06 In addition to above the Cl. No. 188.8.131.52 of RDSO’s Annexure “H” revised in Dec-2005 of IS : 6680/92 may kindly accordingly be revised as under :Lot Size (in Sample Qty. (in Nos.) Nos.) 1 – 100 01 101 – 500 02 Above 500 03 M/S LEC Method for supply of fan conducting acceptance tests shall be as per Annex D table 3 (Clause 184.108.40.206) of IS: 6680 & Annexure H of RDSO Dec 2005 for Air delivery & Noise level.
RDSO’s comments Based on discussion and Annexure-H of DC carriage fan, Sampling quantity is changed. Modified clause SAMPLING PLAN FOR ACCEPTANCE TEST: Method for sampling of fans for conducting acceptance tests shall be as per the table given below: SN Lot size (in nos.)
1 2 3 4
1-100 101-500 501-1000 Above 1000
Sampling quantity (in Nos.) 5 10 15 20
However, for air delivery, service value and noise level tests, 2 fans for lot size up to 100, 4 fans for 101 to 200 and 6 nos. for lot size of above 200 will be selected at random from the lot.
M/S R.Kanwar Before 100% introducing of these Sensor Less BLDC Fans in the Railways, first of all the performance of the same may kindly be watch for atleast 3 years by providing the “Optional Clause” for the procurement of only 10% of Sensor Less BLDC Fans of the Total Required Qty.
RDSO’s comments Specification is revised to improve the reliability and standardisation of BLDC fan and is suitable for BLDC fan with and without hall sensor.