Portable Power ???

[len]

I need to power 8, 575 watt source 4 on dimmers. The trouble is there is no electricity nearby, so I have to run from a generator.

Is it possible to use a 7500 watt generator such as Generac Power Systems - GP7500 which has an L14-30R receptacle and connect that to an ETC Smartpak, which currently has an L21-20 plug on it? Obviously, an adapter would need to be built, which I can have done. Fortunately, the generator and the dimmer can be right next to each other so there won't be a long cable run required.

The alternative would be a bunch of shoebox dimmers, but since all I have are smaller, Leviton, etc., which are only RATED for 2,400 watts (except the power cord is only rated for 15A so I'd need at least 4) I'd rather use the larger, rack dimmer if possible. Suggestions?

 

[JD]

Although the capacity is there on the GP7500, the pack is wired with an L21-20 which indicates it is configured for 3 phase power (HX,HY,HZ,N,G)
Adapting it to two hots on a single phase gene would leave you with an out of balance load as two of the feeds would have to be combine.
The total load for eight 575 watt lamps is 38 amps, or about 12.6 amps per leg if distributed over the three phases. That would put 25.2 amps on one leg and 12.6 amps on the other leg. Not the best layout, but would work as long as you didn't punch everything on at once. (Remember, inrush is your enemy on a gene.)
Almost better to use shoe-box dimmers so 4 fixtures end up on each leg. That works out to 19 amps per leg. (a little over 19)

If you can get an Generac XG8000, you may be better off. Just had first hand experience running my house off one for 9 days (thank you Sandy) and was impressed at how it ran and how well it handled sudden loads. Noise level is about middle of the road for a portable like that.

 

[derekleffew]

You'd need to reconfigure the SmartPack for 1Ø (split-phase) power, abandon the red (or whatever color goes to the pack's L2) wire, and install an L14-30P. Instruction are in the SmartPack Portable Setup Guide.pdf.

 

[JD]

Of course it is a 12 pack and you are only running 8 lights. You could simply distribute the 8 so there is only four loads on each of the legs.

Since the OCPD on the gene is 30 amps, you are probably better off with Derek's advice since the L21-20 is only a 20 amp connector.

Kind of odd now that I think about it. Draw on that pack is 40 amps per leg, and it's equipped with an L21-20 ?

 

[len]

Kind of odd now that I think about it. Draw on that pack is 40 amps per leg, and it's equipped with an L21-20 ?

Bot it used for another project and it never came to pass. Been sitting around gathering dust for a while.

 

[derekleffew]

...Kind of odd now that I think about it. Draw on that pack is 40 amps per leg, and it's equipped with an L21-20 ?

len didn't state whether it was a SmartPack 12x1.2kW (SL1210) or 6x2.4kW (SL620).

 

[JD]

len didn't state whether it was a SmartPack 12x1.2kW (SL1210) or 6x2.4kW (SL620).

True. With 8 loads, I assumed it was the 12. DPC mentality here

 

[len]

Actually, it's a 6 x 2.4K.

I'd prefer to use the one smartpak because it's outdoors, and it would be easier to keep one dimmer rack dry (even tho it's December and I'm not really expecting any rain/snow) than run power to dimmers, plus data lines between all of them.

 

[ejsandstrom]

Please be aware that the Generac is "Full Field" type voltage regulation. It is not going to handle non-linear loads like a dimmer very well. The voltage is not going to be stable and you could damage your dimmer.

 

[JD]

Please be aware that the Generac is "Full Field" type voltage regulation. It is not going to handle non-linear loads like a dimmer very well. The voltage is not going to be stable and you could damage your dimmer.

Depends on the model. The XP series is electronic regulation: Generac Power Systems - XP Series 8000 Watt Generator with Electric Start
"TruePower™ technology provides clean, smooth operation of sensitive electronics, tools, and appliances." (or so the sheet says)

I know the GP is field self-regulation.
Not sure about the XG. If it wasn't snowing out, I would fire mine up and throw a dimmer on it to see what happens. One thing is for sure, it has a real fast governor on it! Barely a flicker when the well pump, furnace, or sewage pump would start. However, "Brush-less" means a field cap, so it may very well not like dimmers. I would stick with the "brush" type XP as it does have the electronic regulator system.

 

[len]

I only linked to Generac because it had a good photo of the connection. Don't own a generator, although it's on the list for next year. So you're saying an XP series would be the way to go?

 

[JD]

Portable Generators use two methods to regulate power.

The "Field Cap" type have an exciter coil in the field windings and a rectifier built into the armature. They can be abused more, are brush-less, but have higher distortion and less than perfect regulation. The GP series are these.

The electronic regulator type have brushes and an electronic regulator circuit that provides a very exact output and low distortion. The XP series are these and are quite a bit more expensive. Because of the non-liner load with lighting, this would be the safest to use.

Funny as it sounds, I have an XG but it's in a shed covered in snow right now, so I could not swear to which it is
I suspect it is "Field Cap" as well, but I went with it over the GP because the "X" series have a pressurized lube system like a car, as compared to the "splash" system like a lawn mower. Also, my primary need was for a reliable house backup that could be portable and gasoline fired as we do not have natural gas service in my area.

EDIT: Just found this really great article on different types of generators being used in the film industry, covers regulation, brush vs brushless, etc.
http://www.screenlightandgrip.com/html/emailnewsletter_generators.html
Site loads slow but worth it.

 

[ejsandstrom]

Portable Generators use two methods to regulate power.

The "Field Cap" type have an exciter coil in the field windings and a rectifier built into the armature. They can be abused more, are brush-less, but have higher distortion and less than perfect regulation. The GP series are these.

The electronic regulator type have brushes and an electronic regulator circuit that provides a very exact output and low distortion. The XP series are these and are quite a bit more expensive. Because of the non-liner load with lighting, this would be the safest to use.

Funny as it sounds, I have an XG but it's in a shed covered in snow right now, so I could not swear to which it is
I suspect it is "Field Cap" as well, but I went with it over the GP because the "X" series have a pressurized lube system like a car, as compared to the "splash" system like a lawn mower. Also, my primary need was for a reliable house backup that could be portable and gasoline fired as we do not have natural gas service in my area.

EDIT: Just found this really great article on different types of generators being used in the film industry, covers regulation, brush vs brushless, etc.
ScreenLight & Grip's E-Newsletter
Site loads slow but worth it.

I may disagree slightly with this. Every commercial generator is brushless. Digital regulation is FAR better than anything with slip rings. It is not subject to noisy loads and reacts to load swings faster and with a tighter tolerance. In most cases less than 1% deviation (4.8V for a 480v system) verses 10%+ (48v on a 480v).

Brushes are used as a cost saving measure and have a limited lifespan.

There are also PMG type which are better yet. But are the most expensive.

If you are going to buy new, avoid a small generac portable at almost all costs. Pick up a comercial grade Onan.

 

[JD]

I may disagree slightly with this. Every commercial generator is brushless. Digital regulation is FAR better than anything with slip rings. It is not subject to noisy loads and reacts to load swings faster and with a tighter tolerance. In most cases less than 1% deviation (4.8V for a 480v system) verses 10%+ (48v on a 480v).

Brushes are used as a cost saving measure and have a limited lifespan.

There are also PMG type which are better yet. But are the most expensive.

If you are going to buy new, avoid a small generac portable at almost all costs. Pick up a comercial grade Onan.

Well, you are talking about a different class and price range. The gene's above are in the $1,000 to $2,600 range. Large commercial generators are a whole different animal. Both digital and analog AVR can be delivered brushless through a controlled exciter winding in the secondary stator, but again, not in the low price portable range. Pulse Modulation (Think switcher) can produce tight voltage regulation and maintain an excellent waveform, but are usually above $10k.