Tow Generators, Cam Locks, and More...Oh My!

[Nick Gardner]

I have the 2 honda 120amp set up. They are about as loud as a standard tow or truck mounted genny. Electricity will kill you dead no matter what it comes out of, big genny or little genny. All the same rules apply. The thing I like about them is that they can fit in the back of a van, you can split them up, move them around, etc. Rather than running 300' of cable, you can just stick one of the generators way over there and run that 4k, then use the other one closer to set. I did a large shoot with them recently and was very happy. But to be fair, I own them and know how they work, but my gaffer and the electricians are the ones who mess with them. I do camera stuff ;-)

Nick

 

[Les Hillis]

Thanks for the insights Nick.

 

[Paul Dean]

Nick and others have mentioned running the larger Honda portable-type generators in parallel... would those more accessible kinds of portable units be considered easier or better to use when starting out than the larger towed units?

Yes, you don’t have to be an experienced electric to operate paralleled Honda EU6500s because the transformer/distros, used to step down the 240V output to 120V, automatically balance the load of whatever you plug into them. A large part of a film electrics job is knowing how much power a light will draw and distributing the lighting load over the two or three legs of the generator so that the generator is balanced.

Always bear in mind that a generator is a mechanical device. It generates electrical power by rotating an electro-magnet (called a Rotor) inside a ring of copper coils (called a Stator) at extremely high-speed (1800 rpm.) The quality of the power (voltage and frequency) is a function of how smoothly it rotates. Lighting loads pull current on separate sets of coils in the Stator. Each set of coils supplies power to a separate leg of the distribution. If one leg of the distribution is more heavily loaded than the others, it pulls harder on the spinning Rotor which can knock it off balance so that it does not spin as smoothly, thereby effecting the quality of power generated. The washing machine analogy that B Kanegson used is a good one. The centripetal force of an unbalanced load during the spin cycle will cause a washer vibrate violently and, if it is out of balance enough, to stop or break.

Since it is a property of step-down transformers that the load placed on the 120V secondary is split evenly over the 240V primary, a transformer/distro automatically balances a lighting load over the legs of the generator. This means that you don’t need to know how many amps each light will draw and you don’t need to meticulously balance them over the legs of the electrical distribution. The transformer does it automatically.

Paul Dean

 

[Les Hillis]

Thanks Paul, appreciate the extra info.

 

[Robert Hart]

For what it is worth, for better or worse, there follows below some handling notes for the big pre-loved 12K HMI light I recently renovated, the Lightmaker Electronic ballast which came with it and a Chinese-built 240VAC 20K generator. Hopefully, those who know the lighting craft will put right any incorrect or dangerous information contained.

WARNING: None of the following notes are approved by the manufacturers and vendors of the products described. The reader is cautioned to seek advice of qualified electricians and lighting technicians before attempting any use of these products and preferably to raise the money to hire these people and not do it yourself.

Please consider these notes only as pointers towards possible hazard you should be aware of and not as a product manual in which you can have trust. This has been copied from my post on dvinfo.net.

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DESISTI 12K HMI LAMP HANDLING NOTES.


Before connecting power to the ballast.


1. Check lamp interior pigtail wingnuts and cable fasteners on carriage for looseness.

2. Daily dust off any transport or environmental debris off the globe. If the lamp has been transported unwrapped on unsealed roads, it will be full of fine dust. Convective airflows will raise the dust and it will fall on the hot globe and fuse into the envelope, shortening its life. Brush and vacuum out the lamphouse enclosure before using.

3. Clean globe with a clean wipe and methylated spirit, otherwise transport debris will fuse into the globe and ruin it. Allow the globe time to rewarm to room temperature before striking. Methylated spirit chills when it evaporates and there will be uneven temperatures in the globe envelope.

4. Check lamp transport is on "spot" with carriage at rear of lamphouse.

5. Leave plastic bags on the cable connectors until ready to plug in. Due to being old, corroded and baulky, the connectors have been lightly greased and will pick up dirt if dragged on the ground uncovered.

6. Close lamphouse door and listen for "click" of safety switch.

7. Plug in the cable to panel socket at rear of lamphouse. Twist collar as you push until collar "clicks".

8. Tie off the cable with lanyard to the blue frame to relieve the panel socket of cable weight.

9. Plug lamp cable into ballast. Hold the weight of the cable and gently push the plug in, rotating the collar until it "clicks".

10. Do not pull any tight turns on the cable as the ballast casework is not strong and will bend. If the ballast is on a platform, tie off the cable with a lanyard to relieve strain on the panel socket.

11. Make sure the generator or power feed to the ballast is itself "off" and the power cable to the ballast is not "hot". The ballast power switch is a "soft" switch. The ballast itself is potentially "live" when power is live on the cable.

12. Make sure the power rocker switch on the ballast is "off". It is American switching which is the opposite of Australian with "off" being down, not up.

13. Connect the generator power cable to the ballast. Hold the weight of the cable and push gently as you rotate the collar until it "clicks".

14. Do not pull any tight tuns on the cable to avoid straining the panel socket and ballast casework. Tie off the cable with a lanyard if the ballast is on a platform to relieve strain on the panel socket.

15. Switch on generator power. I prefer to baseload the generator with a 1000watt load like a worklight beforehand.

16. Switch on the ballast power rocker switch upward. The fans should start and there should be a click inside as a relay triggers after half a second or so.

17. On the outlet face of the ballast, check that the frequency select LED is not lit for "all". This is the flicker-free setting and should not be used to start the lamp.

18. On the rear of the lamphouse are two mini rocker switches identified as "On" or "Off".These are remote triggers which signal the ballast. They are momentary switches and do not click on or off

19. To start the lamp, press the "On" switch on the lamphouse or the "Strike" button on the "power supply" face of the ballast. If the lamp does not strike, there will be a discontinuity in the safety/off closed circuit.

20. The lamphouse will buzz for a few seconds then quieten. The globe should light, flicker a bit and brighten up after about a minute.

21. Please do not hot restrike the lamp or stab relelentlessly at a hard start. The ballast is early-generation and may not tolerate it. The inrush current burns out a resistor and that's that.

22. Please do not move the light on its stand with the globe lit. Please be gentle with hot tilt adjustments. Steep tilt adjustments may either break the glass lens or pool hot air in the electrical area.

23. To switch off the lamp, preferably use the "off" switch on the rear of the lamphouse or the "power" switch on the ballast if the lamp is inaccessible. Please do not switch the power off at the generator.

24. Please do not allow the generator to run out of fuel or be shut down with the lamp operating. The ballast will attempt to gain up the power as the voltage drops and may be damaged.

25. Please allow the globe 30 minutes to cool off before a move is attempted.

26. When disconnecting the cable plugs from the panel sockets, please draw directly outward on the plug body and twist the collar, which should drive the plug out. Please do not jerk on the cable or wriggle it. The panel itself will move and eventually fracture the internal wiring at the internal panel socket connections.

27. To carry the lamphouse, tilt the yoke fully upright and tighten the wing-nuts. There is a carry handle in the yoke frame on each side. Please do not allow the lamphouse to bang down. The globe is carried on springs and will break if they shake about.

28. Please use a platform when assembling the lamp onto the crank stand. Please do NOT assemble the lamphouse to the stand in a reclining position and tilt the assembly upright as the globe on its springs will hang forward and may break. The top-heavy stand may also get away, go right over and come down on top of somebody with the full weight of the lamphouse.

 

[Robert Hart]

SAFETY.


The barn doors assembly will not easily rotate as there are no anti-friction surfaces or rollers in its supports. Its weight must be fully supported before attempts are made to rotate it. Jerking or forcing the rotation may bend the fittings and the barn doors assembly may drop free if the lamphouse is tilted forward.

There should be no other human activity beneath the lamphouse when it is being rigged in a high position. The barn doors assembly shoud be secured to one of the upper front carryhandles or the baseframe by a metal lanyard if the lamphouse is mounted high overhead. The work area immediately below should be a no-go area for crew and cast other than the lighting crew running the lamp. The work area below should be a hard-hat zone.

There is an earth connection between the lamphouse and generator but the lamp itself is not double-insulated like modern domestic appliances. Ideally it should be handled with workshop gloves to minimise any potential shock hazard and heat hazard. The upper sides, top and front of the lamphouse become extremely hot.

The front door should not be opened with any cast or crew in front of it. An exploding globe can project heavy sharp fragments a far distance.

The front door should not be opened without eye and hand protection being worn because of explosive fragmentation hazard.

If rain or other water spillage falls on the lamphouse, be aware this is an early model lamphouse of its type and that the upper vent is not self draining.

Water is shed into the lamphouse within the front and rear of the enclosure, then will drip through into the base where some of the supply wiring and door safety switch wiring runs are positioned. This is a serious safety hazard.

The heat resistant wiring insulation is woven and may hold moisture after some years of operation. Assume the wiring has become dangerous and will be ruined if the lamp is operated.

Attempts to relight the wet lamp may be successful but carbon tracking may develop along the outside of the woven wiring insulation and in the phenolic board insulation of the booster transformer.

The encapsulation material in that circumstance may also become flammable or melt onto persons below and cause burn injuries. Steam will also be driven off and may cause internal arcing which may ruin the ballast.

Try to avoid fogger smoke drifting through the lamphouse. This material may have a high moisture content and in humid weather, may cause arcing within the lamphouse and may ruin the ballast.

The front door should not be opened until the globe has had fifteen to thirty minutes to cool down. If the door is opened too soon, thermal shock may cause a hot globe to explode as internal gas pressures will remain very high.

Please do not sit on the lamphouse. The upper vent is made of lightweight folded sheetmetal with sharp corners which may cause injury if the vent collapses inside.

Please do not use fingers through the wire mesh in front of the glass lens to pull the door open. It may bend and pull out of its light metal frame.

Please do not slam the front door closed. It is not an automatic latch. Push it gently against the lamphouse doorframe whilst swinging the latch knob around into its groove to be tightened down.​

 

[Robert Hart]

CONT'D FROM ABOVE.


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THE LIGHTMAKER BALLAST. HANDLING NOTES.


This electronic ballast is of the first generation of type and does not have the improvements or protecton circuits of later developments. There is a PCB control board which is hard-mounted to the internal frame and has no protection against mechanical shock. The ballast, whilst awkwardly heavy should be handled extremely gently or the PCB and its plugged in components may be damaged. Such damage may be of small initial consequence but may set off a cascade of serious damage through the remainder of the ballast circuit. Some of the high current carrying parts are no longer available as new build replacemwent..

This electronic ballast is not double-insulated therefore it is possible for high voltage and current potentials to be transfered to the case if internal wiring works loose. It is not waterproof and is fan cooled. Ideally it should be operated by persons wearing workshop gloves to minimise shock hazard.

The ballast should not be operated on damp ground, loose dusty ground or grass.

Free movement of air should not be blocked. The ballast should not be placed in a room corner where it will recirculate its own hot air back into itself and overheat. Outdoors, the ballast should be oriented so that prevailing winds will not stall the airflow driven by the pair of fans at one end, otherwise it may overheat.

Objects should not be stored or placed on the ballast case.

Persons should not sit on the ballast case, especially if it is operating as there are electromagetic fields and high capacitive potentials within. A spilled drink or a sweaty backside could really make for a bad day. The jury is also now out on whether low-frequency EMF is as benign as people have previously thought.


FEEDER CABLES.


These may appear robust but are easily damaged. They are also a high value item to replace. Once the outer cover is cut or damaged, it is a throw-out item. Being run over by vehicles may damage the seven strands of internal wiring with the thin signal conductors being especially vulnerable. If the plugs and sockets get wet, whilst sealed from new, gaps do open up and moisture in the voltages present will cause carbon tracking and permanent breadown of insulation. The entire plug or socket has to be replaced as no servicing of subassemblies is conveniently accessible in Australia.


GENERATOR.


There is an emergency RED stop button at the top left of the operating door. Find it and KNOW where it is before doing anything else.

Coolant and oil levels should be checked before operating. The main power breaker switch should be "Off".

After starting, the engine should be allowed to come up to temperature before loading but not left in an unloaded state for more than say fifteen minutes or cylinder glazing may occur.

Periodically the oil-pressure and temperature digital meter should be checked. It reads coolant temperature, battery charge voltage and oil-pressure in a rotating sequence.

Make sure all connected appliances are switched "off" before switching the circuit breaker to "On".

At end of duty, switch off all appliances, then switch off the circuit breaker. Leave the engine running for another ten to fifteen minutes before shutting down. This helps the engine internal temperatures to settle and avoid the generator stator and armature from becoming heat-soaked and damaged without the engine driven fan operating to cool it.

To avoid stalling the fan-driven cooling airflow through the generator enclosure and casuing the engine to overheat, the front end of the trailer should face downwind.

The front gate of the trailer should be lowered to allow exhaust gases to get away. Flammable objects should not be stored on the front of the trailer or drawbar. Diesel engines under loads can throw sparks and may set fire to flammable objects like dufflebags and clothing. For the same reason it should be parked when operating on an open clearing free of dry leaves and grass or a paved surface

The sequence of powering up and powering down is covered above in the Desisti notes.

It is not recommended to operate other appliances as well as the big Desisti light from the same generator. Due to the electrical characteristics of the Lightmaker Ballast, the waveform of the electrical current is deformed and may damage other electrical equipment.

 

[Robert Hart]

CONT'D FROM PAGE ABOVE.

HAZARDS.


The generator should be parked on a level surface and the wheels chocked to prevent rolling if it is disconnected from a parked towing vehicle.

The trailer has no braking system. It is loaded right up to the limit at which a trailer braking system is mandated by law.

There is a jack-up jockey wheel on the drawframe. The mass of the generator has been positioned to give a small front weight bias. It should remain relatively level however if a tyre goes flat, then the jockey wheel will be loaded. The trailer hitch could drop and injure someone of the jockey wheel is released without being wound down.

The generator on the trailer presents a high concentration of mass. Hauling up a steep hill will introduce a lifting moment upon the trailer hitch. The safety chain should be connected at all times even when moving short distances within the private property. Hauling downhill will introduce a strong downward force on the trailer hitch which will lift the front wheels of the towing vehicle to lightness under braking leading to aloss of control. Use the lowest gear and engine braking when moving down steep slopes.

This high concentration of mass makes the trailer and generator more likely to overturn on bends at highway speeds. The steering is likely to be less stable when travelling downhill under braking.


ELECTROCUTION.


Avoid just having the nearest person operate the generator and switches. It should be a SINGLE specialist's job to avoid mixed messages and confusion.

Cables and connectors should not be used if they have been damaged.

If there is rain or irrigation spray in the area, the generator and electrical appliances should not be operated. Electrical operations during inclement weather is a specialist craft for which few of you if any at all have been trained.

There is a very remote chance due to mechanical mishap, of the diesel engine "running away" and becoming impossible to shut down. A likely culprit may be the cold start injection and preheating system failing after a cold start and feeding raw diesel fuel directly into the engine. After startup there will be normally lots of smoke but the engine should settle to a steady speed and the smoke clear after about a minute or two. There may be a light blue oil mist for about ten minutes afterwards until the engine reaches its full operating temperature under load.

If the engine speed runs very fast and erratically, there is lots of really thick smoke and the key or emergency stop button do not shut it down, there is a long-handled stop tap on the fuel tank accessible through the left service door to your right and high as viewed through the door. Once this tap is turned off by pushing the lever towards the opposite side away from you, the engine will continue to run on the remaining fuel in the hoses but starve of fuel after about a minute and shut down. Manually forcing the injector pump control to the cut-off position may not help.


FIRE EMERGENCY.


In the event of a loud crash from the motor and an engine bay fire, if the motor continues to run, it should be stopped with the emergency STOP button as soon as possible before the wiring burns through and disables this function. If there is a lot of smoke and steam and a crackling frying sound of boiling water and oil, do NOT open the doors. There may have been a mixing of hot flaming engine oil and coolant which will be atomising within the enclosure. With air rushing in through the opened door, this mist will flare out at you and ignite. The best you can do is cover the front and rear vents and top inspection holes of the enclosure with wet blankets and let the fire self-extinguish.

Water should not be used to put out the fire due to hot engine oil turning the water to steam, which will atomise the burning oil into a massive flare-up. Dry powder or CO2 extinguishers only. Dry powder extinguishers will also cause a blowback or flare as the powder turns to vapour so stand well back if using one.

The lower enclosure of some generators is intended to contain the full amount of any flammmable liquid which the internal fuel tank or engine oil pan can release. However this is not guaranteed if a broken engine part penetrates both the oil pan and the enclosure. This containment also depends upon the generator being operated completely level and not tilted on a slope. The build quality of the lower enclosure of this generator has not been checked for liquid tightness. Whilst diesel fuel may not have initially leaked into the fire, the fuel tank is a gravity tank and the fuel lines will burn through and release the fuel within a few minutes. Turning off the stop tap will avoid this if it can be safely done with a broomstick. Eventually, the see-through fuel level telltale window will also burn through and let the fuel escape into the fire.

If the front and rear air vents and two inspection ports on top of the enclosure are covered with wet blankets and the doors closed, an oil fire may eventually self-extinguish. Do not open the door to have a look until time has passed and the enclosure is cool to touch, otherwise there may be a vapour explosion.

If there has been a catastrophic structural failure of the engine and the entire oilpan of hot oil has been released, do not attempt to tow the burning generator away or the flaming liquid may splash out through the front or rear vents and spread the fire to the property. Hot engine oil is very fluid like water and flows very quickly.


FOOTNOTE:

The generator described above is a basic and simple diesel-powered machine. There are more modern machines in use which may, in a very rare circumstance, enter into a condition known as "runaway". This is a state in which the motor can neither be controlled nor shut down. Sometimes this may occur because of an electrical or mechanical fault in the control system.

However some diesel engines powering generators in the 30K or higher class may have a turbocharger fitted to improve performance. If a turbocharger fails, the engine may run up to full speed and make huge amounts of thick smoke. In this circumstance, the engine has begun to run on its own lubricating oil being spilled into it by the failed turbocharger.

The only means to stop the engine is to block its source of air for combustion. The most effective and least dangerous means to do this is to set off a CO2 fire extinguisher and direct its output into the engine's air intake. If the engine has been in a runaway state for some time and becomes overheated, BE AWARE that the cooling system may have become over-pressurised, may burst and spray scalding water on anyone nearby. DO NOT attempt to block the air intake with your bare hand. Severe injury may occur. A thick piece of plywood or scrunched rag may do the job.

Do not direct water into the air intake to stifle the combustion. This will hydrolock the engine and cause it to fail catastrophically, with loose parts flying out, possibly voiding an aerosol of water and oil outside of the enclosure which will ignite in a fireball, injure you and possible set off a large fire.