C. Crane 19f Especificaciones descargar pdf (Pagina 12)

Earthing

A.The generating set should be connected to earth in

accordance with local regulations.

B.All metal-work of the generating set should be bonded

so that there is a continuous low impedance path from

all parts of it, including the engine and bed-plate, back

to the earth point.

C.The size of the cable used for the main earth

connection should be of adequate size.

D.If residual current protection is required for personnel

protection it should not be fitted to the generator circuit

breaker. This can cause spurious tripping, but should

be fitted to the sub circuits requiring the protection.

E. If residual current protection is fitted to the generator

circuit breaker, care should be taken for the earth cable

connection, as the connection point will determine

whether the generator windings and the load are

protected, or only the load is protected.

F. When fitting residual current protection care should

be taken to ensure that there is only ONE earth path to

the main earth point.

G.Earthing all metal-work WITHOUT connecting it to the

generator star point will not give earth protection for

the generator load.

H.If the generators are operating in parallel the star

points can be connected in parallel provided this does

not cause parallel paths for the earth protection, or

cause excessive circulating currents

I. The generating set and all associated equipment,

control and switch gear panels must be earthed before

the set is put into operation.

J. 4 numbers earth pits are required as per Indian

Electricity rules or local electricity board.

● 2 earthing pits for genset / control panel body

● 2 earthing pits for neutral

K. GI strips of suitable size may be used for earthing.

Earthing should be checked at earth strip and the

resistance should be less than 1 ohm. For gensets

with AVM’s between engine / alternator and base rail,

the earthing MUST be done at the engine / alternator

and NOT at base rail.

L. The neutral of the generator is not bonded to the

generator frame as supplied from the factory. An earth

terminal is provided inside the terminal box adjacent to

the main terminals. If the set is required to operate

with the neutral earthed, a substantial earth conductor

(normally equivalent to one half of the section of the

line conductors) must be connected between the

neutral and the earth terminal inside the terminal

box.Additional earth terminals are provided on the

generator feet.

Installation Recommendations

Electrical design

H.The terminal box is most conveniently glanded on

either right or left hand side. Both panels are

removable for drilling/punching to suit glands/or

glanding boxes. If single core cables are taken through

the terminal box side panel, an insulated or non-

magnetic gland plate should be fitted.

I. Incoming cables should be supported from either

below or above the box level and at a sufficient

distance from the centre line of the generating set.

This would avoid a tight radius at the point of entry into

the terminal box panel, and allow move ment of the

generator set on its anti-vibration mountings without

excessive stress on the cable. Before making

final connections, test the insulation resistance of the

windings. The AVR should be disconnected during

this test. When making

connections to the

terminals the

incoming cable

termination should be

placed on top of the

winding lead

termination/s and

clamped with the nut

provided.

J. Care to be taken, that weights of cables should not

fall on alternator / base rail. It is recommended to

support output cables on separate structure on ground.

K.External wirings, when provided for remote

voltage / excitation monitoring / droop CT etc. shall be

screened sheathed type. Maximum length of such

wiring should not exceed 5 meters.

L. Power cables should be type installed in a duct or a

cable tray.

Electrical design

Cable access from either side or

above

Overhead Cables

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C. Crane 19f Especificaciones Pagina 12

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