IS 4894 FOR CENTRIFUGAL FAN PDF

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.

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However, if regulators are required, this shall be a matter of agreement between the purchaser and the supplier.

IS – – Centrifugal fans | QuestIn

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. The inlet airway diameter D used in the computation shall be measured after- manufacture. This requirement is applicable for all positions in the normal use.

The test voltage shall be applied as follows: Search the history of over billion web pages on the Internet. The guards shall be securely attached and shall be adequately rigid to resist accidental contact with the blades. The following additional information in respect of an electric centrifugal fan shall be supplied by the manufacturer on request: In the case of indirectly driven fans, the electric motor shall conform to the relevant Indian Standard, 1.

This is normally shown in graphical fashion, following performance tests carried out in accordance with Intermediate values of d, may be obtained by linear interpolation. The value of r may be taken as 1 “4 for atmospheric air. When the guards are in two pieces, positive locking arrangement to keep the two pieces together should be made.

These are intended to prove general quali- ties and design of given type of fan. If more iw, the flare may be remo- ved for the test. Part 1 Methods of testing performance’, issued by the British Stand- ards Institution. For routine and acceptance tests, instruments of class index 2 may be used.

Manaksanstha Common to all offices Telephone,,’Sales Office in Calcutta is at 5 Chowringhee Approach, P. Details of conditions under which a licence for the use of the Standard Mark may be ie to manufacturers or producersmay be obtained from the Bureau of Indian Standards.

The following information in respect of an electric centrifugal fan shall be 489 by the purchaser on request: 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.

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In the case of fans for use on three-phase, two separate earthing centrifuggal shall be provided. Such an addition shall then be regar- ded as a part of the fan. Such fans shall be specially marked. Part 1 General requirements second revision.

Never- theless, fans made to work in higher cooling air tem- peratures may be regarded as complying with this specification provided the temperature-rise centrifhgal are reduced corresponding to the increase in cooling air temperature.

If the fan is specified for two or more distinct rated voltages with three or more supply terminals, the tests shall be carried out at the most unfavourable voltage. The difference between the inlet volume flow at the intersection and the specified inlet volume flow that is, the duty point shall be recorded as the measure of departure of the fan from the specified perfor- mance.

The resistance measurement shall be made with a current of lOA with a dc voltage not exceeding 6V. It is positive when above and cwntrifugal when below the ambi- ent pressure.

As type test, this test should preferably be done immediately after the temperature-rise test. Note — The need for specifying limits of noise levels acoustical of the fans is recognized.

Part 55 Electric fans. 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 4849 and operated by the producer.

When the air flow, in cubic metres per hour, is numeri- cally less than 16 times the airway diameter in cetnrifugal, then the coefficient of discharge shall be taken appropriate to the Reynolds number given in Table 2.

Proper types of bearings should be used to ensure a reasonable amount of silent operation. This value shall fall within the range of specified tolerances. centriufgal

IS 4894: Centrifugal fans

These insulat- ing materials are detailed in IS: For Reynolds numbers of and above, the coeffi- cient of discharge is 0″ and will cover the majority of fan tests. The screen may be composed of one or more layers of even wire or iiabric supported by a wire guard. This is also commonly known as wheel diameter. Note — The trade name, voltage and the size of the fan shall be marked on associated regulator. 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.

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The absolute pressure of the ambient atmosphere is the barometric pressure. While taking the current and watt read- ings during these tests, however, the voltage shall be maintained at the test voltage. The handle or knob shall be so designed that it does not become loose in use. 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.

In the case of inductance type regulator, it is essential that no portion of the inductive winding should remain permanently short-circuited in any of the running positions. A recommended sampling plan is given in Table 3. In case of doubt, the tests shall be carried out at all voltages. The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard.

The copper losses shall be calculated on the corresponding current at the duty point of the fan. Standard marked products are also continuously checked by BIS for conformity to that standard as a further safeguard.

However, it has not been found possible to specify these limits at present on account of: