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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These insulat- ing materials are detailed in IS: The handle or knob shall be so designed that it does not become loose in use. Note — The trade name, voltage and the size of the fan shall be marked on associated regulator.

The criterion of noise level may, therefore, be subject to an agreement between the manufac- turer and the purchaser. 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 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. As type test, this test should preferably be done immediately after the temperature-rise test. Intermediate values of d, may be obtained by linear interpolation.

Search the history of over billion web pages on the Internet. This value shall fall within the range of specified tolerances.

IS – – Centrifugal fans | QuestIn

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 method of measurement of the speed of fan shall be such that the speed of the fan is centridugal appreci- ably affected. In ffor 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: Such fans shall be specially marked.

The copper losses shall be calculated on centrifuga, corresponding current at the duty point of the fan. It is always positive. 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.

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Full text of “IS Centrifugal fans”

It is positive when above and negative when below the ambi- ent pressure. 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.

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.

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

Manaksanstha Common to all offices Telephone,,’Sales Office fzn Calcutta is at 5 Chowringhee Approach, P. The most probable operating point for the fan shall be at the intersection of the fan characteri- stic and the system resistance line. The guards shall be securely attached and shall be adequately rigid to resist accidental contact fir the blades. Centrifugal fans [ETD 5: The value to be adopted for the temperature of the cooling air during a test shall be the mean of the readings of the thermometers taken at equal intervals of time during the last quarter of the duration of the test.

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This is also commonly known as wheel diameter. While taking the current and watt read- ings during these tests, however, the voltage shall be maintained at the test voltage.

IS 4894: Centrifugal fans

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 inlet airway diameter D used in the computation shall be measured after- manufacture. This is normally shown in graphical fashion, following performance tests carried out in accordance with 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.

A fan with protective electrical insulation may be of all-insulated construction or have either double insulation or reinforced insulation. Note — The need for specifying limits of noise levels acoustical of the fans is recognized.

For routine and acceptance tests, instruments of class index 2 may be used. 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.

When the guards are in two pieces, positive locking arrangement to keep the two pieces together should be made. However, it has not been found possible to specify these limits at present on account of: Standard marked products are also continuously checked by BIS for conformity to that standard as a further safeguard.

The absolute pressure of the ambient atmosphere is the barometric pressure. Note — Nevertheless, fans made for other freque- ncies centrifugao be considered to comply with the specifica- tion provided they do so in all other relevant respects.