1. Biodiesel Usage in LitePOWER Generators → Top

Every LitePOWER generator delivered after June 2007 can be fueled with biodiesel fuel without any modification. All other LitePOWER generators can be fueled with biodiesel with one minor modification that can be done at a nominal charge. We have experienced LitePOWER generators running on biodiesel fuel for the last 8 years with no negative side effects.

Biodiesel has many benefits and is becoming very popular, especially in the motion picture and entertainment industries. Our purpose here is not to "sell" anybody on the benefits of biodiesel but to inform our customers of the proper use of this fuel.

We use Cummins diesel engines in our LitePOWER generators and most of the information we have gathered about biodiesel is from their engineering department. Following are several bulletins and articles we have gathered while learning about the use of biodiesel that we would like to share with you.

If you are using biodiesel and have experiences you would like to share with us please let us know. Anything new that we learn will be added to our database and added herein.

List of Articles and Bulletins

• Cummins Announces Approval of B20 Biodiesel Blends
• Biodiesel Fuel Line
• Cummins Application Engineering Bulletin
• Link to National Biodiesel Board website

2. Knot Code for Feeder Cable → Top

How do you tell the phases on feeder cable when it isn't color-coded or when you are working in poor lighting conditions? Most Cam Loc 4/0 feeder cable is not color coded, the connectors are black. All lug type feeder cables are not color coded unless someone has put colored tape on them. The problem is that the tape falls off or gets so dirty you can't tell the color.

Here's how it's done. Tie a sash cord on either end of the cable. Tie knots in the cord as follows:

• Black Leg - Two knots on one side.
• Red Leg - One knot on one side.
• Blue Leg - No knots.
• Neutral - One knot on each side of sash cord.
• Ground - Two knots on each side of sash cord.

Please note that I have not identified the phases as Leg 1, Leg 2 or Leg 3. This is because there are no standards and the phase colors is different from market to market!

3. Phase Color Codes → Top

Because there are no written standards for color-coding of the phases we have to ask the customer their preference. On all LitePOWER generators the legs are clearly labeled as Leg 1, Leg 2 or Leg 3.

If the customer has no preference we use the following colors for our LitePOWER generators. This seems to be standard in the East and Midwest. We've noticed that these companies use the same color-code in their distribution boxes. Indu Electric, Union Electric, Mole Richardson, Crouse Hinds, and Lex Products.

• Leg 1 - Black
• Leg 2 - Red
• Leg 3 - Blue

In California, especially the LA market, the color code that is requested is as follows.

• Leg 1 - Red
• Leg 2 - Blue
• Leg 3 - Black

And here is what has been requested from British Colombia.

• Leg 1 - Red
• Leg 2 - Black
• Leg 3 - Blue

Obviously, it's important to be able to identify the different legs for balancing loads. It is especially important to know the legs when paralleling generators together. The phase relationship of each generator must be matched. If not, it could ruin your day!

4. HMI Flicker → Top

To fully understand HMI flicker you must first realize two of the basics.

The light source, HMI, is a strobe light. When using magnetic ballast, the globe is ignited 120 times per second with 60hz current.

The camera, at 24 frames per second with a 180 degree shutter, has an exposure time of 1/48th of a second.

This yields 2.5 flashes per exposure, an uneven number, and this is the problem. Imagine, better yet, draw a sine wave on a piece of paper. Make the sine wave with about three up humps and three down humps. Draw a straight line through the center. Each time the line intersects the sine wave there is 0 voltage. At the peak of every hump is the maximum voltage (typically 120V). One cycle lasts from the zero voltage point through one up hump, back to zero, through the down hump and then back to zero voltage.

The HMI ignites at maximum voltage and then decays at 0 voltage, over and over. We perceive this as continues light but obviously it is not. The film is exposed by 2 1/2 of these flashes.

Take a separate piece of paper and cut a hole in that is 2 and 1/2 flashes (humps) long. Slide it slowly along the sine wave you have drawn and try to imagine the variations in light level that will be produced as you expose different parts of the sine waves. This variation in light level is called HMI flicker. The faster the window is moved across the sine wave the more noticeable the flicker is.

Our challange is to keep the window from moving across the sine wave, or at least make it move so slowly that the change in exposure is not perceptable. This is done by controlling the camera and generator speed very precisely.

Cameras, because of independant sound recording requirements, operate at an accuracy or 50 parts per million or better. They are locked in at 24 FPS and are not a problem.

Generators are the weak link in this senario. We must control the frequency (engine rpm) to within plus and minus 2 tenths of a cycle from 60 HZ. (59.8 to 60.2) We do this with "precision speed controllers" but it requires everything in the system to be stable and operating perfectly. That is why generators are monitored so closely on sets.

5. Paralleling → Top

Paralleling connects two electrical devises together so that they operate as one. The most common use is where 2 generators are connected together or are connected to the local power grid. This is also called "load sharing"

To parallel two generators together; one is started and connected to a load via a common buss connection. The second generator is started and adjusted (manually or via electronics) so that the voltage, frequency and phase relationship are exactly the same. The moment that all three are correct the second generator is connected to the first. This connection can also be manual or automatic, depending on the equipment you are using. From that point on the two sources will act as one. The voltage, frequency and phase will be locked together as if the two had a common crankshaft.

The most common reason for using paralleling in our industry is when 100% redundant power is required. Typically, this would be for live television or events. The way it works is that you parallel two sources of power and run each at less than 1/2 their capacity. Should one go down, the other would take up the load and continue on seamlessly. This can be done with several generators as well. For example, you could configure 3 generators to share the load. It is also possible to parallel generators to the local power grid. Generally, for our type of equipment, 2 generators are used.

Burrell Enterprises, Inc.
3526 Lakeview Parkway #177, Suite B, Rowlett, TX 75088
Phone: (972) 475-8111 - Toll Free (866) 474-8111 or (800) 474-8111 - bob@litepower.com

Copyright (C) 2004 Burrell Enterprises, Inc., All Rights Reserved