Works Instruction for the Floodlights – Tabard RFC.

ContentsIntroduction...........................................................................................................................................1

Technical Description of Floodlights......................................................................................................1

Tools Required for Replacing Bulbs.......................................................................................................1

Using an EWP.....................................................................................................................................1

Using the “A” frame...........................................................................................................................2

Using an Elevating Work Platform (EWP)..............................................................................................2

Lowering the Units................................................................................................................................2

General..............................................................................................................................................2

Loads.................................................................................................................................................2

Attaching the frame...........................................................................................................................2

Lowering............................................................................................................................................3

Raising the Floodlight........................................................................................................................4

Replacing the Bulbs...............................................................................................................................4

General Outline.................................................................................................................................4

Method..............................................................................................................................................4

Single Mounting.............................................................................................................................4

Two Mounted floodlights..............................................................................................................5

Replacing the Ignitor.............................................................................................................................6

Electrical Spares Required.....................................................................................................................6

IntroductionThe floodlights at Tabard RFC are 13 metres above the ground. To access them a two man Elevating Work Platform (EWP) may be used, with the capability of reaching all parts of the housing. The floodlights can also be lowered as a unit using the “A” frame available on site. The “A” frame and its lifting strops will need to be tested before use.

Technical Description of FloodlightsThe Tabard floodlights are of the Metal Halide variety. They operate on 400 volts, obtained from two phases of a three-phase supply. They are rated at 2 kW. With the metal halide bulbs, an electrical discharge across a mixture of gases emits the light. To start the lamps an “ignitor” is used.

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When the lamps are on, the internal resistance lowers and, to prevent the current getting excessive, a ballast inductor is used to limit the current. The ignitor is mounted aloft, with the actual floodlight while the ballast and other circuitry is in the base. The ballasts work on variable voltages and it is not known whether they are all the same or “tuned” to each floodlight. Whatever system is used the floodlights work as a balanced system and if one light fails, this can affect others in the system. Conversely, by replacing bulbs or ignitors on one floodlight another one may also come on.

Tools Required for Replacing Bulbs

Using an EWP1. Elevating Work Platform (EWP) capable of reaching at least 13 metres. Preferably higher

and capable of accessing all round the light, without the support vehicle moving.2. Large (Ratchet) ½” square drive socket wrench.3. 13 mm spanners/sockets and hexagon wrench for removing the bottom cover, if necessary.4. Large Ring Spanners/Socket 30mm, or in extremis, a Stilsons Wrench, for the bracket bolt.5. Flat bladed screwdriver about 5mm.6. “Mole” Grips.7. “Gas” pliers.8. Adjustable or 10 mm ring/open ended spanner for the elevation clamp1.9. Pliers.10. Club Hammer.11. Thread releasing spray can (WD40).12. Rag for wiping glass.13. Cable ties and cutters in case they need replacing. 14. If replacing the ignitors, a battery powered electric drill and electricians wiring tools. If a

new ignitor box is required then the tools and equipment to mount this box.

Using the “A” frame

15. The “A” frame, complete with hauling strops and 50 mm ratchet strap16. A large FWD vehicle and, if possible, a 1ton SWL winch (Tirfor).17. Bottle Jack and timber baulk.18. 24mm ring spanner/socket for undoing the base holding down nuts19. Large Tractor type tyre for lowering the floodlight stanchion onto.

Using an Elevating Work Platform (EWP)The bulbs can also be replaced by using an EWP. The hoist must be able to reach a height of 13m. Preferably higher and capable of accessing all round the light without the support vehicle moving.

1 This size is not confirmed, have a selection of spanners available.

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Lowering the Units

GeneralA special “A” frame is available for lowering the complete units. Before using the frame carefully inspect it to make sure it is sound. The lifting strops that are with it should also be carefully inspected to look for any damage. As there is no way of testing the rig it is advisable to secure the strop assembly to the base of the floodlights and pull them with the vehicle to ensure they are capable of taking the weight. To check the frame after it is attached it is suggested that the whole rig is loaded in similar fashion before lowering takes place.

LoadsThe approximate maximum load on the hoisting rope is shown below:

Length of Pull Rope m Load Kgs40.15 417.2424.11 418.2615.10 420.76

NB. These figures assume a total stanchion and fittings weight of 250 kgs, a figure obtained from a similar set up.

Attaching the frameThe frame must be secured to the floodlight stanchion at the attachment point by bolting and then secured with a 50mm ratchet strap around the base.

LoweringThe floodlight is lowered by using a vehicle as a movable anchor. To release the stanchion a hydraulic jack is used. The floodlight is best lowered onto one of the tractor tyres available.

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Raising the FloodlightLifting is a reversal of the lowering procedure.

Replacing the Bulbs

General OutlineThe bulbs are replaced by lowering the glass downwards as it hinges at the front. The glass is held in place by clips that pivot outwards. The bulb has a spade terminal at each end which is connected under a screw fixing. The bulb is held in by a rotating slide.

On the supports with two floodlights the floodlights have to swung at right angles to the cross arm for the glass to be lowered.

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Method

Single MountingUse the hoist to reach the lamps. Spray the four holding clips so that they can pivot. Undo the finger screws above the lamp housing to free off the clips. Check each one moves and if not, use the mole grips or gas pliers or other implement to swing it round. When happy all clips can be moved, undo them so that the floodlight glass can be lowered under control. If the glass hits the lamp housing or mounting bracket, then the hook bolt, holding the lamp in elevation, needs to be slackened (one bolt each side) and the lamp housing pushed up to enable the glass to hinge down.

The old bulb is then released at the terminal screws first and then the rotating slide is moved away and the bulb removed.

While being careful not to touch the bulb casing, the new bulb is put in position, and the slides rotated round to grip it. The spade terminals are then put in position and gripped by the screws, tightly.

The floodlight glass is then replaced and the clips rotated back into position. Tighten the finger screws and the hook bolts if they were loosened. Then lower the hoist.

Two Mounted floodlightsThe main sequence is as above but the lamp housing bracket may also have to be released and rotated at right angles to the cross arm to enable the glass to hinge down. The nut can be very tight and may require the use of the club hammer to release it. Spray with WD40 to help with releasing.

The position of the lamp should be noted before rotating, so that it can be put back in the same position.

After replacing the lamp turn the lamp housing back into position (if necessary) and tighten the nut.

Replacing the Bulb

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The finger screw and clip

The Bulb and fixings

Replacing the IgnitorIt is highly likely that the ignitor may also need replacing. The venture supplied one does not fit into the existing ignitor box and the ignitor must be fitted into a new box fitted outside the floodlight. The new ignitor is wired via the old ignitor box.

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New Ignitor and box, wired into old Ignitor

Electrical Spares RequiredFor the old lights: Radium HRI-TS 2000W/D/S/400/K12S or Equivalent

For the new lights: Philips Master MHN-FC 2000W/740 400V XW

Ignitor: Venture PT150K445 1500-2000W MH SIP IGNITOR or equivalent

If using Venture ignitor, a new weatherproof box minimum size 155x115x77 mm (LxWxD).

Peter Cook

History

Issue 2.0 September 2019 – Updated.

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