Bosch Power Tools 1375-01, 1375AK manual Distribution Network

Page 37

generator or converter to the power consumer must be rated so that the switch-off current IA of the next upline excess voltage protection unit according to table I VDE 0100 –

§9 N will at least be activated when- ever a complete short circuit bet- ween an outer conductor and the neutral conductor occurs at any point in the circuitry.

One can also use fault current cir- cuit breakers in addition, as shown in Fig. 6 (illustrated, for the sake of simplicity, for single-phase current). The FI circuit breaker receives its impulse from a current transformer through which all of the lead wires inclusive neutral conductor pass. The secondary coil of the current transformer supplies the activation current for the relay coil of the FI circuit breaker. The wires surrounded by the current transformer generate an alternating magnetic field in the core of the transformer if all of the currents do not neutralize each other in sum total (Fig. 7). During fault-

The relay coil in the FI circuit breaker is activated (Fig. 7). 45 mA FI circuit breakers are available for 265 V/200 Hz rotary current. FI circuit breakers for rotary current at other voltage and frequency levels must be specially requested from appropriate manufacturers.

A schematic representation of an FI circuit breaker is provided in Fig. 8. In order to accommo- date the regulations and specific conditions in other countries, Bosch offers high-frequency elec- tric tools for various operating

voltages (265 V, 135 V, 72 V, 42 V at 200 Hz; 200 V, 72 V, 42 V at 300 Hz). At the lower voltages, however, only a few high-frequency electric tools should be used in close pro- ximity to the associated frequency converter. This is because the currents arising at high power levels and low voltage require cable cross-sections that would

be too large.

Fig. 6

THE DISTRIBUTION NETWORK.

free condition of the FI circuit breaker, the current flowing to the consumer is of exactly the same magnitude as that flowing back from it. Thus the two currents neu- tralize each other. There is no resul- ting induction onto the secondary coil of the current transformer, and the relay coil of the FI circuit brea- ker remains currentless (Fig. 6).

If there is a fault condition at the FI circuit breaker, a fault current flows off through the earth; the currents in the current transfor- mer are no longer all mutually neutralized and induction results. Voltage is induced on the secon- dary side of the transformer.

The distribution network must not have any connection with the existing 50 Hz supply mains. For this reason, special CEE plugged connections as per DIN 49462/63 and DIN 49465 are prescribed for frequencies between 100 and 300 Hz. The housings for the plug, coupling box and wall socket are all green. The different shape of these plugged connections prevents existing 50 Hz plug units from being combined with either the plugs or the coupling boxes. Depending on practical require- ments, either movable or fixed leads may be used for the distri- bution network between the

frequency converter and the individual high-frequency electric tools.

The transmission of high power levels at low voltage is unecono- mical in broadly distributed installations. There will either be high installation costs due to the large lead cross-sections required or else transformers will be needed to reduce the higher voltage at the place of tool operation.

Presupposing a constant level of power transmission, predefined voltage drop and equal lead length, the lead cross-section is inversely proportional to the square of the voltage, i.e. half the

voltage will require a lead cross- section that is four times larger. The required distribution network cross-section can easily be deter- mined by refering to Figs. 9 to 12. The admissible voltage drop

of 5 % from ohmic resistance, the admissible temperature increase and the voltage drop from induc- tive resistance are all taken into account in calculating lead cross- sections. The illustrations are to be read as follows:

72

Fig. 7

73

Page 36 Page 38
Image 37
Page 36 Page 38
Contents TOP Contents HIGH-FREQUENCY Power Tools Inexpensive Power ApplicationAN Overview with a Single Click ALL Industrial Tools Online DrillsOver N/mm Iron N/mm Selection Guide for DrillsCast180 20 to 15 to 10 to 50 to 30 to 80 to Drill diameter mmDrills Accessories for Drills Dimensional Drawings DrillsRecommended Speeds for HSS Twist Drill Bits 16 mm, B16Grinders Idle rpm With abrasives Selection Guide for GrindersNumber Selection Guide for Grinders Disc and Random Orbit SandersWithwheels ShapedFor grinding points Straight GrindersTo 50 mm in diameter CompleteVoltage 27 to 50 mm in diameterHGS 57/50 Ls HGS 65/3240 to 50 mm in diameter PowerHGS 77/50 HGS 85/40For grinding wheels 50 to 80 mm in diameter Switchtype Remarks ComeswithComplete Speed HGS 77/75125 to 180 mm in diameter For grinding wheelsRemarks Comeswith 100 to 180 mm in diameter Angle GrindersWith 180 to 230 mm in diameterHWS 85/180 HWS 88/180HWS 810/230 For grinding wheels 230 to 300 mm in diameterHWS 810/300 Disc sanders and random orbit Disc Sanders and Random Orbit SandersSanders for sanding discs with Mm diameterAccessories for Angle Grinders Dimensional Drawings Straight Grinders Dimensions mm 602 210 602 211 602 245 602 243 Dimensional Drawings Angle Grinders Screwdrivers Dimensional Drawings Disc Sanders Random Orbit SandersTorque accuracy depending Selection Guide for ScrewdriversOn screwdriver system Screwdriving typeCUT-OUT Screwdrivers With adjustable cut-out Clutch for screws fromTo M Impact wrenches for Impact WrenchesScrews from M 6 to M SquareTappers for threads up to 8 mm in diameter TappersHGR 55/10 Current withoutSpecial Accessories for Screwdrivers Accessories for SHUT-OFF ScrewdriverDimensional Drawings CUT-OUT Screwdrivers Dimensional Drawings Angle Wrenches Dimensional Drawings Impact WrenchesAccessories Balancer Loadmin LoadmaxBalancer For loads From 0.3 to 17 kgPlug CONNECTIONS, Leads Robust Technology for LONG-TERM HEAVY-DUTY USE Stator Rotor HousingFan Sample calculation for a Tool installationHigh-frequency electric Network groupsFrequency converter with synchronic generator Designing AN Installation for HIGH-FREQUENCY Electric ToolsParallel operation of frequency converters Compensating for reactive currentElectrical Safety Distribution Network Cable cross-section as a function of voltage and lead length Bosch Service Quality
Related manuals
Manual 32 pages 42.47 Kb
Top Page Image Contents