Comments. IS Code. Recent; Popular; Featured. IS – – Pallets for materials. Buy BIS IS (R) SPECIFICATION FOR CENTRIFUGAL FANS from SAI Global. Standard Air. Centrifugal fans for use in mines and hazardous atmospheres may requirt: additional requirements to be met, not covered by this standard.
The guards shall be securely attached and shall be adequately rigid to resist accidental contact with the blades.
For routine and acceptance tests, instruments of class index 2 may be used. If more convenient, the flare may be remo- ved for the test. When the guards are in two pieces, positive locking arrangement to keep the two pieces together should be made. Part 1 General requirements second revision. Note — Nevertheless, fans made for other freque- ncies shall be considered to comply with the specifica- tion provided they do so in all other relevant respects.
A fan with protective electrical insulation may cenrrifugal of all-insulated construction or have either double insulation or reinforced insulation. Manaksanstha Common to centrufugal offices Telephone,,’Sales Office in Calcutta is at 5 Chowringhee Approach, P.
Note — The need for specifying limits of noise levels acoustical of the fans is recognized. The value of r may be taken as 1 “4 for atmospheric air.
It is always positive. The most probable operating point for the fan shall be at the intersection of the fan characteri- stic and the system resistance line.
These are intended to prove general quali- ties and design of given type of fan. The absolute pressure of the ambient atmosphere is the barometric pressure. The resistance measurement shall be made with a current of lOA with a dc voltage not exceeding 6V. These insulat- ing centrifygal are detailed in IS: Such an addition shall then be regar- ded as a part of the fan.
This revision has been undertaken to take into account the experience gained since then and to align some of the safety requirements with the provisions of IS: Part 55 Electric fans. The handle or knob shall be so designed that it does not become loose in use.
While taking the current and watt read- ings during these tests, however, the voltage shall be maintained at the cehtrifugal voltage. The Standard Mark on products covered by an Indian Standard conveys the assurance that they have been produced to comply with the requirements of that standard under a well-defined system of inspection, testing and quality control which is devised and super- vised by BIS and operated by the producer.
The openings – shall be flush with the duct and free from burrs and countersinks. In the case of fans for use on three-phase, two separate earthing terminals shall be provided. Full text of ” IS Capacitors shall comply with IS: Intermediate values of d, may be obtained by linear interpolation. Details of conditions under which a licence for the use of the Standard Centrifuval may be granted to manufacturers or producersmay be csntrifugal from the Bureau of Indian Standards.
Note — In this specification, the term ‘fan’ shall be used to mean centrifugal fan ccentrifugal supplied, without any addition to the inlet or outlet, except where such addition is specified. Part of Motor or Rboulatob Class A Class E Tbmpbbatukh-Risb, “C Method OF Mbasu- BBMBNT 6 Change of resi- stance Change of resi- stance Insula- tion 3 60 60 Insula- tion 4 75 75 Class B Insula- tion 5 80 80 The temperature-rise shall not reach such a value that there is a risk of injury to any insulating material on adjacent parts of the regulator 40 40 40 Thermo- meter Thermo- meter 1 2 i] Insulated win- dings of motors ii Insulated wrin- dings, if any, of regulator with conti- nuous runn- ing on any contact iii Regulator resi- stance unit with conti- nuous runn- ing on any contact iv External surfa- ces likely to be touched during normal usage Note 1 — The thermocouples, if used, should be applied only to external surfaces which may be reached by an ordinary thermometer.
Full text of “IS Centrifugal fans”
Note — The trade name, voltage and the size of the fan shall be marked on associated regulator. The fixed losses and copper losses shall be calculated in accordance with the details given in IS: This test shall be carried out with the guard if any, in position.
It is positive when above and negative when below the ambi- ent pressure. Part 1 Methods of testing performance’, issued by the British Stand- ards Institution. This is normally shown in graphical fashion, following performance tests carried out in accordance with The other limbs of the manometer shall be opened to the ambient atmosphere and the manometer reading shall be taken as equal to the average static pressure in the airway.
In case of doubt, the tests shall be carried out at all voltages. When the air flow, in cubic metres per hour, is numeri- cally less than 16 times the airway diameter in metres, then the coefficient of discharge shall be taken appropriate to the Reynolds number given in Table 2. The stray load loss is assumed to be percent of the shaft power. The copper losses shall be calculated on the corresponding current at the duty point of the fan.
A recommended sampling plan is given in Table 3. As type test, this test should preferably be done immediately after the temperature-rise test. In the case of indirectly driven fans, the electric motor shall conform to the relevant Indian Standard, 1. The following additional information in respect of an electric centrifugal fan shall be supplied by the manufacturer on request: Proper types of bearings should be used to ensure a reasonable amount of silent operation.
A system resistance line shall also be drawn, passing through the specified duty point such that the total or static pressure varies with the square of the inlet volume flow see Fig.
Never- theless, fans made to work in higher cooling air tem- peratures may be regarded as complying with this specification provided the temperature-rise values are reduced corresponding to the increase in cooling air temperature. The test voltage shall be applied as follows: However, if regulators are required, this shall be a matter of agreement between the purchaser and the supplier.
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IS 4894: Centrifugal fans
Standard marked products are also continuously checked by BIS for conformity to that standard as a further safeguard. The ‘Running’ and ‘OFF’ positions of the regulator shall be distinctly and clearly marked and the indicator on the operating handle or knob shall correctly indicate the position of the regulator. The inlet airway diameter D used in the computation shall be measured after- manufacture. Note — The difference in pressures is the mean pressure when facing tube reading is employed.
For Reynolds numbers of and above, the coeffi- cient of discharge is 0″ and will cover the majority of fan tests. This value shall fall within the range of specified tolerances.
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