Generator requirements for continous lighting

[J. Winfield Heckert]

I have a Northstar 13000 ppg generator. It has a honda motor, and provisions for 220/110 hook ups. It will power a whole house and is rated to power computer equipment. I want to know if it's suitable for film lighting and if it will surge or flicker at 24fps or higher rates to film slow motion.

I know they have generators for film lighting but if this works I'd like to save the rental money. I know it will be loud.

 

I shot a some test footage, with it powering the lights but need to finish the roll and send it off.

[JD Hartman]

No personal experience. It provides approximately 50A@220VAC or 10k watts continuous. Good and bad things are reported in the reviews for that model on the Northern Tools website. Yes, it's very loud and one owner commented that the voltage regulation was very poor.

[Guy Holt]

I have a Northstar 13000 ppg generator. ...I want to know if it's suitable for film lighting and if it will surge or flicker at 24fps or higher rates to film slow motion.

 

A generator like this has limited applications in filmmaking. You can use it if you are using only incandescent lights (not the most efficient source), you are not recording sound, and you are not using the generator as your primary supply for tech equipment like monitors, lap tops, hard drives, and battery chargers. If you want to use other light sources like HMIs, Fluorescents, & CLF lamp banks, it matters not only what type of generator you use but also what type of HMI & fluorescent ballasts you use. The harmonic noise that non-Power Factor Corrected electronic ballasts (both HMI & Kino) draw can have a severe adverse effect on the power waveform of conventional AVR generators like this one. The harmonic noise these light sources generate will not nearly have as bad an effect on the power supplied by an inverter generator like the Honda EU6500is or EU7000is.

 

For more details on what type of generator to use with HMIs and fluorescent lights use this link for an article I wrote on the use of portable generators in motion picture production.

 

 

Harry Box, author of “The Set Lighting Technician’s Handbook” has cited my article in the Fourth Edition of the handbook. Here is what he has to say about the article:

 

"Great work!... this is the kind of thing I think very few technician's ever get to see, and as a result many people have absolutely no idea why things stop working."

"Following the prescriptions contained in this article enables the operation of bigger lights, or more smaller lights, on portable generators than has ever been possible before.

 

Guy Holt, Gaffer

ScreenLight & Grip,

Lighting Rental & Sales in Boston

[J. Winfield Heckert]

It would only be used to power Incadencent light, However I just found out I have 2 curcuits with in 150ft of the location. 15amp and a 20amp, and possible power from the neighbors house thats even a little closer. The location is a quarry that will be lit to look like the interior of a cave. so the Genny may just be a back up.

[Phil Rhodes]

How much 12V DC can you get out of it? You can always run inverters.

 

P

[Edward Lawrence Conley III]

150' is pretty good distance for little 12g extension cords, worse if you use a 14g ext cord.

 

 

The best way to utilize this generator would be to wire up a 14-50 plug that feeds out to a pigtail with 5-15 connectors- assuming your lights are 2k and smaller.

 

This would make it easier to balance out the load on the genset.

 

The manual doesn't have a diagram to indicate which outlets are on the which windings.

 

http://www.northerntool.com/images/downloads/manuals/165923.pdf

 

You could use the 2- 120v Duplex receptacles- 20amps each- NOTE- the 20amps is for the 2 on the left and 20amps for the 2 on the right. NOT 20amps for each one.

 

Then get a pigtail for the 30amp 120v receptacle.

http://www.amazon.com/gp/product/B002MGJ2F4/ref=pd_lpo_sbs_dp_ss_3?pf_rd_p=1944687582&pf_rd_s=lpo-top-stripe-1&pf_rd_t=201&pf_rd_i=B00BHGXYRC&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=1WTP5ADTG8ZKD7XKTAW0

[Guy Holt]

You could use the 2- 120v Duplex receptacles- 20amps each....Then get a pigtail for the 30amp 120v receptacle.

http://www.amazon.com/gp/product/B002MGJ2F4/ref=pd_lpo_sbs_dp_ss_3?pf_rd_p=1944687582&pf_rd_s=lpo-top-stripe-1&pf_rd_t=201&pf_rd_i=B00BHGXYRC&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=1WTP5ADTG8ZKD7XKTAW0

 

There are a couple of problems with this suggestion from a code standpoint. First, code requires over current protection within 10ft of a change in wire size, which means the pigtail suggested can only be used with a load that has an integral breaker, like an HMI ballast, that is within 10ft of the generator. If you run out 150' of 12/3 extension cable from this adapter you are in violation of code. Second, revisions to the NEC in 2014 require that all 15-, 20-, & 30A receptacles on portable generators smaller than 15kVA be protected by GFCIs when the 240V twist-lock receptacle is in use. The reason NEC 445.20 requires that there be GFCI protection is that a double fault condition, like that illustrated below, can expose an individual touching faulty equipment to 240 volt potential and a possibly lethal shock. In response to this code change Honda is equipping the new EU7000is with GFCI protected 20A/120V duplex outlets.

Two Faults can create 240V exposure

These code revisions are problematic for users of portable generators for event staging and motion picture production because not only are the hardware store type GFCIs typically used with portable generators designed for home standby power unreliable in these applications, but they can be outright dangerous in that they create the illusion of protection against ground faults when in fact they offer very little (use this link for details).

 

150' is pretty good distance for little 12g extension cords, worse if you use a 14g ext cord.

 

The best way to utilize this generator would be to wire up a 14-50 plug that feeds out to a pigtail with 5-15 connectors- assuming your lights are 2k and smaller.

 

This would make it easier to balance out the load on the genset.

 

This is not the best way to use this generator. Generators like this are designed for home standby power applications and do not bond ground and neutral. Their neutrals are floating. Without a bonded ground, fault currents will not go to the equipment grounding conductor, but will instead find other means of returning to their source which might be through you. Breaking out from a 14-50 receptacle on a floating neutral generator opens up the possibility of lethal double fault situations like that described above. A better approach is to use a 240V-to-120V step-down transformer at the end of a 240V cable run. Ground and neutral are bonded in transformers, which means fault currents will go to the equipment grounding conductor, thereby minimizing the potential for electrical shock.

 

There are numerous other benefits to using a step-down transformer with portable generators:

 

1) They create a single large 120V circuit capable of powering larger lights, or more smaller lights, than the generator could otherwise.

2) They automatically balance the load on the two legs of the generator – greatly simplifying electrical distribution

3) They cushion the Impact of Large HMI & Tungsten Heads

4) They enable you to use standard distribution equipment

5) They can boost voltage to compensate for line loss.

6) They enable the reliable operation of the Arri 1800W Baby Max.

7) They brings the Honda EU6500/EU7000 into compliance w/ OSHA Regs

8) They mitigates the effects of harmonics on generators.

 

But the biggest benefit to using a step-down transformer with portable generators is that they enable the use of film style GFCI, like the Shock Stops, that won’t nuisance trip under non-linear lighting loads. In fact, since the 2014 revisions to the NEC have resulted in generator manufacturers incorporating hardware store type GFCIs on portable generators, a Full Power Transformer/Distro offers the only means of providing reliable ground fault protection in wet hazardous locations. Since the power from a portable generator can kill you just as assuredly as power from a diesel tow plant, it is critical that you understand how these generators differ from diesel tow plants and what it takes for GFCI devices to operate reliably on them (use this link for details).

 

Guy Holt, Gaffer

ScreenLight & Grip

Lighting Rental & Sales in Boston

[Phil Rhodes]

Well, that all sounds sufficiently miserable and overcomplicated. If there is anything I like about where I work, it's nice, easy, single-phase 240V mains that can handle anything I'm ever likely to throw at it.

[Guy Holt]

Well, that all sounds sufficiently miserable and overcomplicated. If there is anything I like about where I work, it's nice, easy, single-phase 240V mains that can handle anything I'm ever likely to throw at it.

 

The worst part is that because of the revisions to NEC 445.20: Ground-Fault Circuit Interrupter Protection for Receptacles on 15kW or Smaller Portable Generators, manufacturers of portable generators are putting hardware store type GFCIs on their single-phase generators. For example the 20A receptacles on the new Honda EU7000is are equipped with GFCIs with 5mA trip thresholds that are prone to tripping with HMIs and Kinos because of the high frequency residual currents that these non-linear loads generate.

 

To add insult to injury, it doesn't have to be this way. In 2003 UL published a new standard (UL 943) designed to avoid GFCIs from nuisance tripping as a result of residual currents. The new standard allows GFCIs to incorporate high frequency filters and trip on an "Inverse Time Curve." Attenuated by a filter, residual currents don't sensitize GFCIs and so pose less of a problem. An inverse time trip curve permits transient conditions that are sufficiently short in duration so as not to pose a hazard while keeping current through the body to safe levels.

 

Relationship of typical GFCI trip curve to the UL943 Curve

 

Even though the UL 943 inverse-time curve was meant to enable GFCIs to operate more reliably in real world conditions, manufacturers of lower-priced Class A GFCIs, like those found on Honda generators and in hardware stores, do not implement the curve because it requires sophisticated micro-processors, which makes the design more complicated and the GFCI more expensive. Instead they use a more aggressive response (like that illustrated above) that is lower and faster than that required by UL 943 (typically 250 ms at 6 mA where UL 943 permits 5.59 seconds.) The more aggressive response of hardware store type GFCIs is permissible because the UL standard is the absolute highest current vs. time response accepted but it is not mandatory. That is, a device will fail UL testing if it responds slower than the standard requires, but will pass as long as the response time is less than the curve time even if it is a lot less.

 

This more aggressive trip curve does not generally pose a problem in the one-tool per circuit applications for which they are designed. After all, power tools are by their nature linear loads that do not generate high frequency harmonic currents. However, the more aggressive trip curve of hardware store style GFCIs has proven to be a problem in applications involving more extensive distribution to multiple non-linear loads, namely the type of distribution that characterizes motion picture production.

 

100A Shock Stop GFCI

 

Which means the only way to safely use generators like the EU7000 with most HMIs and Kinos is to use film style GFCIs, like the Shock Stops, Shock Blocks, or Bender LifeGuards, that are specifically designed to not nuisance trip under non-linear lighting loads. Since the power from a portable generator can kill you just as assuredly as power from a diesel tow plant, it is critical that you understand how these generators differ from diesel tow plants and what it takes for GFCI devices to operate reliably on them (use this link for details).

 

Guy Holt, Gaffer

ScreenLight & Grip

Lighting Rental & Sales in Boston

[Mark Dunn]

Guy, Phil is talking about mains power in the UK. We have 240V, consequently lower currents in cables, and our own, different, standards. For example, all UK plugs are independently fused.

Edited January 7, 2016 by Mark Dunn

[Phil Rhodes]

Only on domestic connectors, to be fair. 16A ceeforms and the 15A stuff used in theatrical lighting isn't, because who wants a blown fuse up on a lighting gantry?

[Mark Dunn]

Just carrying out the educational function of pointing out that some of us don't live in the US and aren't subject to the NEC, whatever that is. Not the National Executive of the Labour Party, that's for sure, or that place in Birmingham.

Though the OP is considering using domestic circuits.

Edited January 7, 2016 by Mark Dunn

[John E Clark]

Just carrying out the educational function of pointing out that some of us don't live in the US and aren't subject to the NEC, whatever that is. Not the National Executive of the Labour Party, that's for sure, or that place in Birmingham.

Though the OP is considering using domestic circuits.

 

National Electric Code....

 

Don't know what the UK version would be, but a casual look indicates that the devices 'we in the US' call Ground Fault Interrupters would be Residual Current Device, or Residual Current Circuit Breaker, and the various EU members have different requirements amongst themselves...

 

I rarely get involved in various electrical code issues... the closest sort of thing would be to verify that my equipment works at 220/240 @ 50 Hz... which is a problem doing here in the US...

 

These days it is just easier to get power supplies that are rated for the 100-240V @ 50/60 Hz and be done with it...

Edited January 7, 2016 by John E Clark

[Guy Holt]

Guy, Phil is talking about mains power in the UK. We have 240V, consequently lower currents in cables, and our own, different, standards. For example, all UK plugs are independently fused.

 

 

I realize where Phil is posting from and I envy his situation. There are major benefits to working with 230-240V European power. Not only are your cables smaller, but since Universal HMI ballasts have an operating range from 195-260V, you don’t really need to be concerned about voltage drop. Here in 120V land, voltage drop is a real issue. Between voltage drop on a small portable generator under load, and line loss on long cable runs, voltage can drop to the point where HMI ballasts won’t strike. This is particularly true when using open frame generators like the being discussed here.

 

A feature film production powered by a Honda EB10000

 

Open frame generators of that size typically put out about 72dbs at 23'. At that noise level the generator has to be moved far off set where it won’t be picked up on the audio tracks, which results in significant line loss from the long cable run back to set. To the problem of line loss, you have the added problem that as you add load, the voltage drops on portable generators (it is not uncommon for a generator to drop 5-10 volts under full load.)

 

Campfire scene on the beach powered by a Honda EB10000

 

The combination of voltage drop on the generator and line loss on a long cable run can cause voltage to drop to the point where HMI and Kino ballasts cut out unexpectedly or won't strike at all. Low voltage can also cause problems such as reduced efficiency and excessive heat in equipment, unnecessary additional load on the generator, and a dramatic shift in the color temperature and in the output of lights (use this link for a details.) For these reasons, portable gas generators are typically operated too close to set where they are picked up on audio tracks. The trick to recording clean audio with open frame generators is to use a boost transformer that enables you to operate the generator at a distance without suffering from voltage drop.

Left: Honda EB10000 operating out of grip truck (note set at distance (bright spot on right side.)) Center: 84A Full Power Transformer/Distro compensates for Voltage Drop over 400ft cable run. Right: Beach Set with 120v full line level 500ft from power source.

 

For example, on the production of “Gasp” the crew ran our modified 10kw Honda EB10000 out of their grip truck 500 ft. from their beach set. To assure full line level on set, the production used the boost capacity of our 84A Transformer/Distro to compensate for the appreciable line loss over the long cable run.

 

Left: Beach Set lit by Arri M18 and 6kw Par. Center: Secondary side power distributed with standard 100 Bates Gang Boxes. Right: Set viewed from generator (note: distance and extent of set power distribution.)

 

From the Transformer/Distro they then ran 4/3 Bates Extension to set where they broke out to 20A Edison receptacles using 100A gang boxes in order to power an assortment of smaller tungsten fixtures to simulate the firelight and an ARRI M18 to simulate moonlight on the actors around the fire. To light the deep background the crew put a 240V Siamese in-line before the transformer/distro to power a 6kw HMI Par. Even with a sizable load, they experienced no appreciable voltage drop on set even after a 500' cable run because the Transformer/Distro compensated for both the line loss of the cable and voltage drop of the generator under near full load.

 

With nothing more than a Honda EB10000 and house power the crew of "Gasp" was able to maintain the look and feel of a sunny summer day even when filming in the midst of a hurricane in October.

 

The principle location for "Gasp" was an idyllic beach house right on the ocean. To light interiors of the beach house, the crew of "Gasp" used the Honda EB10000 to power two 4k Pars coming in from the outside, and house power to power an assortment of smaller HMI and Kino fixtures.

 

Left: Ready for rain on the set of "Gasp." Center: Two 4kw Pars operate on a 10kw Honda EB10000 Generator through our 84A Full Power Transformer/Distro. Right: 100A Shock Block GFCI downstream of Full Power Transformer/Distro offers Ground Fault Protection for entire 100A distro system.

 

The indie film"Gasp" is a good example of how the voltage boost capacity of a Transformer/Distro makes it possible to record clean audio tracks with even open frame generators under the worst of conditions.

 

Guy Holt, Gaffer

ScreenLight & Grip

Lighting Rental & Sales in Boston

 

[Phil Rhodes]

I had a shoot a year or so back in an abandoned water treatment works where the nearest power was a (standard, UK, 13A) wall socket aboutr 100m away. There are 100-metre mains extension cables with 16A ceeforms on the ends, but the tungsten light did get noticeably brighter when we unplugged the wallpaper stripper that was providing steam effects. It's possible to volt drop anything if you try hard enough!

 

On the other hand, on 120V mains, you probably couldn't have run a wallpaper stripper and a modest lighting rig from one socket if it was six feet away, so :)

 

What's really depressing is the level of sophistication that can still call itself an "indie film" over there. You still win. Oh boy, how you win.

[Mark Dunn]

Maybe there's a thesis to be written on how our independent film industry sector has been held back by the 240V standard.

[Adrian Sierkowski]

You'd think it'd've been liberated a bit. perhaps what's more interesting would be linking the decline in indie film with that of home-manufacture as well as distances for trade shipping / number of container ships unloaded. e.g. perhaps its just that getting the "stuff" there is much harder than say, LA, where we can often walk to the factory (note similar problems abounded in Philadelphia when I was there on the ULB)