BS 764-1990 pdf free

04-30-2021 comment

BS 764-1990 pdf free.Specification for Automatic change-overcontactors for emergency lightingsystems.
BS 764 This British Standard specifies d.c. and single-phase a.c.automatic double-pole change-overcontactors for low voltages up to 250 V employed inconjunction with storage batteries or other alternative source of supply, to provide a means ofautomatically changing the current supplied tosafety lights from the normal source to the alternative source when the normal source fails, andof reconnecting the safety lights to the normal source when this source is restored. This standard does not apply to three-phase a.c.automatic change-over contactors.
NOTE 1Appendix B lists information to be supplied to themanufacturer with the enquiry and/or order.
NOTE 2The titles of the publications referred to in thisstandard are listed on the inside back cover.
For the purposes of this British Standard, thefollowing definitions apply.
automatic change-over contactor a complete apparatus for effecting automaticchange-over of the safety lights from the normalsupply to the alternative supply when the normalsupply fails, and for returning the safety lights tothe normal supply when this supply is restored. Thereturn operation may be effected through the agency of a relay which, if employed, is an integralpart of the lights lights which are normally connected to normalsupply and are changed over to the alternativesupply when the normal supply fails, e.g.the safetylights specified under the Cinematograph Regulations.
main contactor apparatus constructed in accordance with thisspecification, excepting the relay if employed.Where the complete automatic change-over contactor is intended, this is made clear in relevantclauses.a voltage dependent relay, the function of which is tocause the main contactor to change from the emergency to the normal position when the mainsupply voltage has recovered to a particular value.contactor coil the shunt connected coil energized from the normalsupply, which causes the main contactor either tochange to, or to remain in, the normal position2.6.
relay coil the shunt connected coil, energized from the normalsupply, which causes the relay contacts to move toone of their two positions.BS 764 pdf download.

Download infomation Go to download
Note: Can you help me share this website on your Facebook or others? Many thanks!
BS ISO 7425-1:2021 pdf free Free BS Standards

BS ISO 7425-1:2021 pdf free

BS ISO 7425-1:2021 pdf free.Hydraulic fluid power cylinders一Dimensions and tolerances of housings for elastomer- energized, plastic-faced seals Part 1: Piston seal housings. 5.2 Axial length For axial lengths for the nominal piston diameters, see Iable3. If the...
Get More
BS EN ISO 8407-2021 pdf free download Free BS Standards

BS EN ISO 8407-2021 pdf free download

BS EN ISO 8407-2021 pdf free download.Corrosion of metals and alloys一Removal of corrosion products from corrosion test specimens. 4.1.6 The true mass of the specimen, after removal of the corrosion products, will be a value between the...
Get More


Anonymous netizen Fill in information