GCK Low Voltage Draw-out Switchgear

Product Overview

The GCK low-voltage withdrawable switchgear is widely used in power plants, metallurgical rolling mills, petrochemical plants, light industry and textile mills, ports and docks, hotels and office buildings for power distribution and centralised motor control in AC three-phase four-wire or five-wire supply systems with voltages of 380 V and 660 V, frequency 50 Hz and rated current of 5000 A and below.

GCK has passed full type tests and obtained CCC certification; it is an assembled advanced-type low-voltage switchgear, designed in accordance with the following standards:

National standard GB7251.1-2005 Low-voltage switchgear and controlgear assemblies

International standard IEC60439.1-1992 Low-voltage switchgear and controlgear assemblies

Type Designation

Service Conditions

• The ambient air temperature is not higher than +40 ℃ and not lower than -5 ℃, and the average temperature within 24 h is not higher than +35 ℃;
• The relative humidity does not exceed 50% at the maximum temperature of +40 ℃; a higher relative humidity is permitted at lower temperatures, for example 90% at +20 ℃;
• The air is clean, free from corrosive and explosive gases and free from conductive dust that could damage insulation;
• The site is free from significant shaking and shock vibration; the equipment is installed vertically with an inclination not greater than 5°;
• The altitude does not exceed 2000 m;
• The switchgear is suitable for transport and storage at temperatures from -25 ℃ to +55 ℃, and up to +70 ℃ for short periods (not exceeding 24 h);
• If the user cannot meet the above conditions, this shall be negotiated with the manufacturer.

Main technical parameters

• Rated insulation voltage 660 V/1000 V
• Rated operational voltage 400 V/660 V
• Rated operational voltage of auxiliary circuits: AC 380 V, 220 V; DC 110 V, 220 V
• Rated current of busbar: 1000 A, 1250 A, 1600 A, 2000 A, 2500 A, 3200 A, 4000 A, 5000 A
• Rated short-time withstand current of busbar: 50 kA, 80 kA (r.m.s.) for 1 s
• Rated peak withstand current of busbar: 105 kA/0.1 s, 140 kA/0.1 s, 176 kA/0.1 s
• Rated current of branch busbar: 630 A, 1000 A, 1250 A, 1600 A
• Rated short-time withstand current of branch busbar: 30 kA, 50 kA (r.m.s.) for 1 s
• Rated peak withstand current of branch busbar: 63 kA, 105 kA/0.1 s
• Degree of protection of enclosure: IP30, IP40
• Busbar arrangement: three-phase four-wire, three-phase five-wire
• Operating mode: local, remote, automatic

Classification of Switchgear

• Incoming cubicle
• Bus-tie cubicle
• Feeder cubicle
• Motor control cubicle
• Power source changeover cubicle
• Power factor compensation cubicle

Structural Features

The basic frame of GCK is of combined assembly structure; all structural parts of the frame are galvanised and plastic-sprayed and connected to each other by screws to form the basic frame, to which doors, baffles, partitions, drawers, mounting brackets, busbars and electrical components are added as required to assemble a complete control centre cubicle. The structure of this cubicle has the following features:

Frame

• The frame is assembled from C-sections; the frame parts and dedicated matching parts are supplied by our company to guarantee the accuracy and quality of the cubicle.
• The forming dimensions of parts, hole dimensions and equipment intervals are modularised (module E = 20 mm, the same below).
• The internal structural parts are galvanised.
• The top cover of the cubicle is detachable, and lifting rings are fitted at the four corners of the cubicle top for lifting and transport.
• The frame is divided into three mutually isolated compartments — the busbar compartment, the functional unit compartment and the cable compartment — which prevents the spread of accidents.

Functional Units (Drawers)

• The height module of the drawer units is 200 mm, divided into five size series: 1/2 unit, 1 unit, 1.5 units, 2 units and 3 units. The rated current of the unit circuit is 630 A and below (see the figure above for the outline).
• Each MCC cubicle can accommodate up to 9 drawers of 1 unit or 18 drawers of 1/2 unit.
• The operating mechanism is mechanically interlocked with the drawer: when the main switch is in the closed position the drawer cannot be withdrawn.
• The operating mechanism of the drawer can be locked in the closed or open position with a padlock, allowing the electrical equipment to be maintained safely.
• The rear of the functional unit is provided with main circuit incoming/outgoing plugs and auxiliary circuit secondary plugs.
• The functional unit compartments are separated by metal partitions.
• The drawer units adopt a rotary racking mechanism with a three-position function, giving simple and reliable operation.
• The GCK drawer racking mechanism moves along a spiral track on the locating parts to rack the functional unit in and out; during racking in and out it provides three-position indication and mechanical interlocking, and is fitted with a microswitch for electrical interlocking in the test position.

Installation & Operation

After the product arrives at the receiving site, first check whether the packaging is intact; if any problem is found, notify the relevant contract department in time to make a commercial record, jointly analyse the cause and carry out certification, and handle the aftermath.

Products that are not installed immediately shall be placed and kept properly in a suitable location in accordance with the normal service conditions and the temporary storage regulations for electrical equipment.

• The product shall be installed according to the installation diagram. The foundation channel steel and the bolts for bolt fixing shall be provided by the user. When connecting the main busbar, if the surface is uneven due to transport or storage, it shall be made flat before connection and tightening.
• When the equipment is installed singly or in a row, the deviations in verticality, unevenness of the cubicle faces and gaps between cubicles shall comply with the requirements of Table 1.

Inspection & Test before Commissioning

• Check whether the paint or other covering material (such as plastic coating) on the cubicle surface is damaged, whether the interior is dry and clean, and whether the mounting screws in all positions are loose.
• Check whether the operating mechanisms of the electrical components are flexible, without jamming or excessive operating force.
• Check whether the making and breaking of the main apparatus is reliable and accurate.
• Drawers or withdrawable mechanisms shall be pulled out flexibly and lightly, without jamming or collision.
• The centre lines of the moving and fixed contacts of the drawer or withdrawable structure shall be aligned and the contacts shall touch tightly. The insertion depth of the main and auxiliary contacts shall meet the requirements. The mechanical or electrical interlock shall operate correctly and both locking and release shall be reliable.
• Drawers with identical primary schemes, secondary principles and dimensions shall be easily interchangeable, without jamming or collision.
• When replacing fuse links, the engineering design requirements shall be met.
• The protection settings shall be set correctly according to the actual load.
• The insulation resistance measured with a 1000 V megohmmeter shall not be lower than 10 MΩ。
• All busbar connections shall be sound and insulating supports, mounting parts and other accessories shall be firm and reliable.

Precautions for Use

• The equipment is a low-voltage distribution cubicle installed away from the wall, operated from the front and maintained from both sides. The maintenance channel and doors of the cubicle may only be entered or opened by qualified professional personnel for operation, inspection and maintenance.
• After the cables are connected, the bottom of the switchgear shall be sealed to prevent small animals from crawling in and causing short-circuit accidents.
• After many opening and closing operations, especially after short-circuit opening and closing, the contacts of air circuit breakers and moulded-case circuit breakers may be locally burnt and carbon deposits produced, increasing the contact resistance; maintenance and servicing shall be carried out according to the circuit breaker instruction manual.
• After installation and maintenance, the isolation between compartments and between functional units shall be strictly checked to ensure good functional segregation of the assembly and to prevent the expansion of faults.

Drawer Operation

Operation of the 1/2-Unit Drawer

The operating mechanism of this drawer consists of the rotating part, the shaft and the latch, and provides the functions of closing/opening, test, isolation and locking of the switch. The operating mechanism is also fitted with a microswitch for electrical interlocking.

Ⅰ Connected position: the main switch is closed, both the main circuit and the control circuit are connected, and the functional unit is locked. (O) Open position: the main switch is open, the control circuit is connected, and the functional unit is locked.

Test position: the main switch is open, the main circuit is disconnected, the control circuit is connected, and the functional unit is locked.

Isolated position: the drawer is withdrawn by 30 mm; both the main and control circuits are isolated and disconnected, and the drawer is locked.

Withdrawn position: both the main circuit and the control circuit are disconnected, and the drawer can be withdrawn freely.

The operating handle can be turned from the (O) position to the (I) position only after being depressed by 6 mm.

Operating sequence: only in the withdrawn position (↑↓) can the drawer be pushed in or pulled out; after turning 45° anticlockwise the drawer automatically reaches the isolated position (↗) when pulled out. Turning 45° clockwise reaches the test position (↑); a further 45° clockwise reaches the switch open position (O). The handle is then depressed by 6 mm and turned 90° clockwise to close the switch; to withdraw, the operations are performed in reverse order. If necessary, a padlock can be added to the operating handle in the three positions of main switch open, test and isolation as a safety safeguard.

Operation of Drawers of 1 Unit and Above

Test: the main switch is open, the main circuit is disconnected, the control circuit is connected, and the functional unit is locked. Disconnected: the main switch is open, both the main circuit and control circuit are disconnected, and the drawer can be withdrawn freely. Connected: the main circuit and control circuit plugs are engaged, the switch can be closed and opened, and the functional unit is locked. I: circuit breaker closed; O: circuit breaker open.

Outline & Installation Dimensions

• The outline dimensions are given in the table below.

• The GCK series switchgear is installed vertically away from the wall; behind it is the outgoing cable trench of the cubicle. For ease of maintenance the distance from the rear to the wall is normally 800-1200 mm, and the front installation distance is shown in the figure below.

3

Operating instructions: set the drawer racking mechanism to the “disconnected” position, turn the hexagon-socket operating handle clockwise to the “connected” position, then turn the operating handle 90° clockwise to close the circuit breaker; the opening sequence is the reverse of the above.

Note: 1. The circuit breaker cannot be closed when the racking mechanism is in the test or disconnected position.

2. The racking mechanism cannot be operated when the switch is in the closed position.

Unlocking Mechanism

There is a round hole at the lower right corner of drawers of 1 unit and above; this is the unlocking mechanism of the drawer door. When the drawer racking mechanism is in the connected position and the switch handle is in the “O” position, pull out the small cover, insert a small screwdriver into the hole and move the latch downwards to open the door. After closing the door the plastic cover must be replaced, otherwise the original degree of protection will be impaired.

Delivery Documents & Accessories

The manufacturer shall supply the following documents and accessories

• Packing list
• Product certificate and factory test report
• Instruction manual
• Relevant electrical drawings
• Instruction manuals of the main components
• Cubicle door keys, operating handles and spare parts specified in the order.

Ordering Information

The user shall provide the following when ordering:

• Main circuit distribution system diagram and layout drawing,Rated operational voltage,Rated operational current,Setting current of the protection device and the necessary technical parameters。
• Specify the specifications of the incoming and outgoing cables。
• Models of the main electrical components in the switchgear,Specifications and quantities。
• If a busbar bridge or busway is required between switchgear cubicles or for the incoming cubicle,The specific data such as span and height above ground shall be stated。
• If the switchgear is used under special environmental conditions,This shall be described in detail when ordering。
• Surface colour of the switchgear and other specific requirements。

Related Products

Low-voltage switchgear of the same series and other types available for selection:

• GGD Low Voltage Switchgear
• GGJ Low Voltage Reactive Power Compensation Device
• MNS Low Voltage Draw-out Switchgear
• GCS Low Voltage Draw-out Switchgear
• GZDW Microcomputer DC Power Screen
• GZDW-1B Wall-mounted DC Power Supply