Singapore Punggol Bridge Project

Brief introduction of the electrical system of HZQ59/80 launching gantry

FAQ Jul 17, 2012 No Comments

segmental assembly bridge girder launching gantry

One important operating principle for HZQ59/80 launching gantry electrical system is to do a movement at one time, then next action to avoid fault, it must be followed especially at starting and stopping operation.
It is strictly prohibited to adjust the movement of other systems if one system is working, especially prohibit to rotate the change-over switch.

Main components of the electrical control system
1 Trolley
1.1 Trolley technical parameters are as follows:
work altitude:≤1000m
working temperature:20ºC ~ +50ºC
class of insulation: F grade
working class: A3
lifting capacity: 80t
power: 380V/3-phase/50Hz
lifting speed: 2.0 m/min
lowering speed with no load: 4.0 m/min
Lifting height: up rail 6m, down rail 2.5m, 8.5m in total
lifting motor type: 2*22kW,
the complete machine lateral moving speed: 0~1.6m/min
lateral moving oil pump motor: 5.5kW
longitudinal moving speed: 0~4.6m/min
longitudinal moving driver: 2×5.5 kW
sling turning speed:0~0.3r/min
sling turning motor:2×0.55kW
launcher climbing gradient: longitudinal gradient 1%, transverse gradient4%
protection grade: IP55
power : 120Kw, 380V, 3-phase, 50Hz
max use power:48Kw, 380V, 3-phase, 50Hz

1.2 Structure introduction
Main overhead crane is made up of lifting system (winch), crane, trolley, sling, crane cable drum, sling cable drum and other system
1)Trolley movement
Trolley movement to the left or right is realized by pushing or pulling movement of two cylinders
Magnetic valve power supply DC24V power 26w
Trolley hydro-cylinder linkage “trolley forward” 1DT、3DT “+”
”trolley backward” 2DT、4DT “+”

Trolley left hydro-cylinder “trolley forward” 1DT、 “+”
”trolley backward” 2DT、 “+”

Trolley right hydro-cylinder “trolley forward” 3DT、 “+”
”trolley backward” 4DT、 “+”

Trolley oil pump motor works by PLC according to automatic command
Trolley Ⅰ hydro-cylinder and Ⅱ hydro-cylinder are controlled automatically by PLC through magnetic valve to move

2)、Winch lifting and lowering
Set up three control positions, after low speed brake opens in the working, limit switches (height limit, over speed switch, weight) on the winch can not work to any direction, when the winch stops working, close high speed brake firstly, close low speed brake 2s later (according to actual situation to adjust). Main shaft of the drum is equipped with over speed switch.
The lifting and lowering of winch system is realized by two sets Schneider Altivar 71 30KW frequency converter driving devices and two sets 22KW variable frequency motors

3)、Crane works
Crane works at two sides at the same time, iron facilities open, YD11~YD14 works, at the same time the iron facility is in the right place and contact of limit switch SQ11~SQ14 is closed, then the launcher can moves and the iron facility stops working. Lock launcher operation device to prevent the launcher working. Launcher moving system is set up three control points. When all motors of the launcher do not work, iron facilities at each side can be open by manual control.
Launcher moving forward or backward is realized by one set Schneider Altivar 312 11kw frequency converter driving device and four sets 5.5kw moving motors

4)、Sling system
Sling system is mainly made up of swing mechanism and hydraulic pressure adjusting mechanism. After the sling moves near to bridge deck, waterproof socket outside the trolley cabin could be power source; as the sling reaches the ground, power supply is from the ground. The sling is in remote control.
Sling swing is finished by one set Schneider Atlivar 312 frequency converter driving devices and two sets 0.55KW rotary motors, be set up at first gear
Adjusting mechanism is mainly made up of one set hydraulic pressure station, 3KW oil pump motor, drive two hydro-cylinder to adjust level degree of the sling, set up at the first gear.

5)、Load limiter
After sending weight signal to signal processing box by sensor PCQ, display real-time weight on the display screen, when lifting load reaches 90% of rated load, give an early warning, the alarming apparatus gives “honk, honk, honk” long intermittent sound, yellow indicating light becomes bright; when lifting load reaches 108% of rated load, limit hook goes up and gives “honk, honk, honk” short intermittent sound, at the same time red indicator becomes bright

6)、Launcher is equipped with crashproof limit switch for left and right

7)、Movement of launcher reel E1 is decided by PLC automatically according to order

1.3 Electrical equipment components
1 power supply control cabinet
1 frequency conversion control cabinet
1 resistance cabinet
Trolley distribution box
1 sling control cabinet
1 remote control unit

Control mode
PLC belongs to Siemens S7-200CN series
Frequency converter uses Schneider Brand
The control system can be controlled by remote control unit and ground control unit, two ways can be alternately used, but one control mode is available at one time, selection for control mode can be decided by “manual operation/remote control” change-over switch on the linkage desk in the cabin, by selecting the position of the switch, it can be decided to use remote controller or ground operating platform, when the change-over switch turns to “manual operation”, only the ground control is efficient, instead remote control is efficient.

Electric distribution system
Launcher power supply is AC 380V, 50HZ, 3-phase, 5 wire system.
Details of each part of the power supply are as follows:
Power supply: 3-phase AC 380V 50Hz
Power circuit system: 3-phase AC 380V 50Hz
Auxiliary power supply circuit: AC 220V 50Hz
Lighting circuit: AC 220V 50Hz
Control circuit: AC 220V 50Hz/DC24V
PLC circuit: AC 220V 50Hz/DC24V
Outlet: AC 220V 50Hz

Electrical safety device
Wind speed protection
Wind speed limit dynamic protection, when wind speed reaches to grade, the alarming apparatus sends “honk, honk, honk” warning tone, wind speed control signal does not be transferred to control system, when the operator finds wind force is more than 6 grade, current work should be finished as soon as possible and stops the machine.

Winch hammer type height limit protection
Hammer limit movement, winch lifting is forbidden

Winch switch to avoid too tightness and too relaxation
Be mainly used to avoid unnecessary danger caused by uneven steel wire rope on the winch.

Launcher limit protection at left and right
SQ11、SQ12 left and right anticollision protection, use reflective type photoelectric sensor to measure the distance, when left and right limit switches begin working, the system will forbidden the movement to the converse direction, at the time the launcher can only move to the converse direction

Launcher support leg iron wedge opening protection
Only when iron wedges of launcher support leg are open normally, the launcher can begin walking.

Launcher motor heat protection
When one of 4 sets 7.5KW motors of the launcher conducts overload overheat protection, the launcher is forbidden to move, at the same time red indicator becomes lighting, the launcher can re-start moving after troubleshooting.

Sling oil pump motor heat protection
Hydraulic driving device of the sling is equipped with oil pump motor overheat protection, once the overheat protection works, the oil pump motor is forbidden to move.

Overload protection
Load limiter
Directly transfer weight signal to two opening and closing signals, then send them to PLC processing device, when lifting load reaches 90% of rated load, give an early warning, the alarming apparatus gives “honk, honk, honk” long intermittent sound, yellow indicating light at root part of the launcher support leg becomes bright; when lifting load reaches 108% of rated load, limit hook goes up and gives ““honk, honk, honk” short intermittent sound, at the same time red indicator at root part of the launcher becomes light.

Over-speed protection
Over-speed switch is set up on the winch, if speed of the winch is beyond the design scope, stop running the winch, low-speed and high-speed brakes will work at the same time.

Lightning protection
Main circuit is equipped with arrester to avoid system damage caused by induction lightning stroke. When the condition is allowable, install lightning rod on the system

Emergency button
Emergency buttons are set up on the remote controllers, ground control panel, launcher support legs, they are used to cut off main power supply rapidly under the emergency condition.

Buzzing alarming in the cabin
When the following things happen:
Launcher left and right limit switches working, lifting up and down limit switches working, oil pump of trolley overheat, motor of launcher overheat, overload, over-speed of winch, launcher frequency converter troubles and lifting frequency converter troubles, buzzer on the linkage will ring.

Crane tower type alarm yellow light
When the followings happen:
Launcher left and right limit switch movement, lifting system up and down limit switch movement, oil pump of trolley overheat, motor of launcher overheat and motor of bottom sling overheat, tower type alarm yellow light will be twinkling.

Crane tower type alarm red light
When the followings happen:
Overload, winch over-speed, launcher frequency conversion trouble, lifting frequency conversion trouble, sling frequency conversion trouble, the tower type alarm red light will be twinkling.

Launcher moving alarm red light
When the launcher moves, red indicator on the launcher support leg will ring.

Lightning system
Lightning at the bottom of the main girder uses 4 pieces of shockproof traffic lights 400W, AC220V.

2 Gantry crane for lifting girders
2.1 Gantry crane for lifting girders technical parameters
working temperature:20ºC ~ +50ºC
class of insulation: F级
working grade: A3
power supply: 380V/3-phase/50Hz
protection grade: IP54
power: 74.6Kw, 380V, 3phase, 50Hz
max use power:44kw,380V, 3-phase, 50Hz

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