The electrical equipment market of the Netherland East Indies

Bibliographic data

Monograph

Identifikator:: 1833098390

URN:: urn:nbn:de:zbw-retromon-221838

Document type:: Monograph

Title:: The electrical equipment market of the Netherland East Indies

Place of publication:: Washington

Publisher:: Gov. Pr. Off.

Year of publication:: 1930

Scope:: II, 46 S.

Digitisation:: 2022

Collection:: Economics Books

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Chapter

Document type:: Monograph

Structure type:: Chapter

Title:: Electricity in industry

Collection:: Economics Books

Nt motors for low tension at full pressure must be at least as much as indicated in the following table: Axle capacity Kilo- watts Horse- Dower 0.35 L5 35 | 11 30 75 0.5 Number of revolutions per minute 2.000 1.500 750 275 Power Power Power factor factor factor 0.72 0.69 0.60 .78 74 L687 .81 .78 .73 .85 .83 L7® .87 . 86 +2 .R8 Re ww Power factor 7g 0 The power factor for single phase motors may be 0.03 lower. The power factor for high-tension motors may be 0.03 lower. The required power factor for motors with axle capacity or a number of revolutions not mentioned in the table must be in ratio to the figures mentioned in the table. 3. Before operating motors the electricity service must be offered an oppor- tunity to, examine the same at the expense of the party who has installed them or the party who uses the current. 4. The mountings of motors and the metal parts of the starting resistances which are not under tension, as well as all the handles, must be properly con- nected with the earth by means of tin-covered copper wire or cable. The earth connection may not be joined to the neutral wire of the installation, nor to gas pipes. The connection with the earth must be approved by the electricity service. 5. Every motor must be provided with working regulations and a switching scheme which shows in which way it is disconnected. . 6. Motors with an axle capacity of not more than 1 kilowatt (1.36 lorsepower) may be switched on with an ordinary 3-pole switch. 7. Motors with an axle capacity of more than 1 kilowatt up to not more than 2 kilowatts for intermittent operation and of not more than 3 kilowatts for continuous operation which have a short-circuit or rotor, must be started with a starting resistance in the stator or a star-delta switch to be approved by the electricity service. Intermittent operation is considered to be operation of the motor for not more than 5 consecutive minutes. The star-delta switch must be of such a design that it can be switched in only two movements from the dis- connected position into the delta position; when switched off it must leave the motor entirely without tension. 8. Motors with an axle capacity larger than 3 kilowatts must be provided either with a slip-ring armature and be started by means of a tarting resist- ance in the rotor circuit or with a short circuit or short-circuit rotor and be started with a starting transformer in the stator, or be equipped with another special device approved by the electricity service by which the strength of the starting current is kept within certain limits. When starting the rofor circuit may not have a tension higher than 300 volts. 9. Motors with a capacity of over 8 kilowatts must be equipped with one or more devices which break up the current carried in all phases and make it impos- sible to start anew until the starting device is brought back to neutral, when the voltage of the system decreases fo more than 50 per cent of normal (auto- matic protection against low tension) for longer than 5 seconds or when the carrying of the current is interrupted in one of the phases. 10. The starting strength of current which is taken from the system, except in special cases, may not be more than 10 amperes higher than the normal full tension strength of current of the motor, except in installations where several motors are being used; the starting strength of current in such installations may not be higher than that of the largest motor. 11. Motors with an axle capacity of more than 10 kilowatts must have in one of the phase wires an ampere meter, which must be easy to read for the persons who operate the starting device. 12. On the starting device the off position must be indicated, and the connect- ing installation must be clearly indicated by an arrow. An inscription must state that connecting must be done slowly. It must be impossible to leave the

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