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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IS – – Centrifugal fans | QuestIn

Such fans shall be specially marked. Note — Nevertheless, fans made for other freque- ncies shall be considered to comply with the specifica- tion provided they do centrifugla in all other relevant respects.

It is positive when above and negative when below the ambi- ent pressure. 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. Standard marked products are also continuously checked by BIS for conformity to that standard as a further safeguard.

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.

This is normally shown in graphical fashion, following performance tests carried out in accordance with The handle or knob shall be so designed that it does not become loose in use. This test shall be carried out with the guard if any, in position.

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. The openings – shall be flush with the duct and free from burrs and countersinks. 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.

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Manaksanstha Common to all offices Telephone,,’Sales Office in Calcutta is at 5 Chowringhee Approach, P. Full text of ” IS The most probable operating point for the fan shall be at the intersection of the fan characteri- stic and the system resistance line.

As type test, this test should preferably be done immediately after the temperature-rise test. Part 1 General requirements second revision. This requirement is applicable for all positions in the normal use.

Full text of “IS Centrifugal fans”

In the case of indirectly driven fans, the electric motor shall conform to the relevant Indian Standard, 1. The resistance measurement shall be made with a current of lOA with a dc voltage not exceeding 6V. 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.

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. 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 number of significant places retained in the rounded off value should be the same as that of the specified value in this standard.

If more convenient, the flare may be remo- ved for the test. A fan with protective electrical insulation may be of all-insulated construction or have either double insulation or reinforced insulation. If the number of defectives found 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.

In the case of a double insulated fan, both basically insulated parts and live parts shall not be accessible to the standard test finger. Capacitors shall comply with IS: The test voltage shall be applied as follows: The criterion of noise level may, therefore, be subject to an agreement between the manufac- turer and the purchaser.

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IS 4894: Centrifugal fans

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.

Centrifugal fans [ETD 5: For Reynolds numbers of and above, the coeffi- cient of discharge is 0″ and will cover the majority of fan tests.

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. A recommended sampling plan is given in Table 3.

This is also commonly known as wheel diameter. These insulat- ing materials are detailed in IS: The absolute pressure of the ambient atmosphere is the barometric pressure. In case of doubt, the tests shall cwntrifugal carried out at all voltages.

The value to be adopted for the temperature of the cooling air during a test 494 be the mean of the readings of the thermometers taken centrifuga, equal intervals of time during the last quarter of the duration of the test. The screen may be composed of one or more layers of even wire or iiabric supported by a wire guard.

Such an addition shall then be regar- ded as a part of the fan. These are intended to prove general quali- ties and design cenyrifugal given type of fan. In the case of fans for use on three-phase, two separate earthing terminals shall be provided.

However, if regulators are required, this shall be a matter of agreement between the purchaser and the supplier. Note — The difference in pressures is the mean pressure when facing tube reading is employed.