IS 4894 FOR CENTRIFUGAL FAN PDF

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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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.

IS 4894: Centrifugal fans

This is normally shown in graphical fashion, following performance tests carried out in accordance with For Reynolds numbers of and above, the coeffi- cient of discharge is 0″ and will cover the majority of fan tests. 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.

If more convenient, the flare may be remo- ved for the test. Details of conditions under which a licence for the use of the Standard Mark may be granted to manufacturers or producersmay be obtained from the Bureau of Indian Standards.

The criterion of noise level may, therefore, be subject to an agreement between the manufac- turer and the purchaser. Note — In this specification, the term ‘fan’ shall be used to mean centrifugal fan as supplied, without any addition to the inlet or outlet, except where such addition is specified.

A fan with protective electrical insulation may be of all-insulated construction or have either double insulation or reinforced insulation. The openings – shall be flush with the duct and free from burrs and countersinks. The following information in respect of an electric centrifugal fan shall be supplied by the purchaser on request: In the case of fans for use on three-phase, two separate earthing terminals shall be provided. Part 55 Electric fans.

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When the guards are in two pieces, positive locking arrangement to keep the two pieces together should be made. Centrifugal fans [ETD 5: The resistance measurement shall be made with a current of lOA with a dc voltage not exceeding 6V.

This test shall be carried out with the guard if any, in position. The copper losses shall be calculated on the corresponding current at the duty point of the fan. 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.

Search the history of over billion web pages on the Internet. However, if regulators are required, this shall be a matter of agreement between the purchaser and the supplier.

As type test, this test should preferably be done immediately after the temperature-rise test. This is also commonly known as wheel diameter. These insulat- ing materials are detailed in IS: The value of r centrifubal be taken as 1 “4 for atmospheric air. The stray load loss is assumed to be percent of the shaft power.

IS – – Centrifugal fans | QuestIn

The ‘Running’ and ‘OFF’ positions of the regulator shall be distinctly and clearly marked and the iss on the operating handle or knob shall correctly indicate the position of the regulator. While taking the current and watt read- centriufgal during these tests, however, the voltage shall be maintained at the test voltage. Note — The trade name, voltage and the size of the fan shall be marked on associated regulator. All metallic parts associated with it shall be protected from accidental contact.

Note — The difference in pressures is the mean pressure when facing tube reading is employed. 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 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. A recommended sampling plan is given in Table 3. Standard marked products are also continuously checked by BIS for conformity to that standard as a further safeguard. Such fans shall be specially marked. In case of doubt, the tests shall be carried out at all voltages. 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.

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Note — The need for specifying limits of noise levels acoustical of the fans is recognized. Intermediate values of d, may be obtained by linear interpolation. If the number of defectives centrifugl in the first sample is less than the rejection number, take a second sample of size indicated in col 3; and if the total number of defectives in the first and second sample put together is less than the rejection number, accept the lot, otherwise not.

It is positive when above and negative when below the ambi- ent pressure. For routine and acceptance tests, instruments of class index 2 may be used.

This requirement is applicable for all positions in the normal use. Part 1 General requirements second fot. Such an addition shall then be regar- ded as a part of the fan. 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.

Cemtrifugal types of bearings should be used to ensure a reasonable amount of silent operation. The guards shall be securely attached and shall be adequately rigid to resist accidental contact with the blades.