How to Calculate the Required Power for a Diesel Generator?

How to Calculate the Required Power for a Diesel Generator? What Are the Basic Matching Calculation Formulas?

A diesel generator is an essential component for any business that requires round-the-clock operation. Regardless of weather conditions or potential natural disasters, the diesel generator should be capable of powering all the equipment necessary to keep the business running smoothly. This means you need a commercial diesel generator that can provide sufficient power for the entire building.

Why is Choosing the Right Size of Diesel Generator Most Important?

An improperly sized diesel generator will not only leave you with unusable equipment but can also damage other electrical appliances in your building that are not intended for such use. Using an undersized diesel generator for your business may cause it to run longer than necessary. This means it will only partially power your electrical equipment, leading them to operate at higher speeds than usual and shortening their lifespan. Additionally, it may consume more fuel, increasing your overall costs, and pose safety hazards such as overheating, which, if unattended, could lead to fire accidents.

On the other hand, using an oversized generator might seem beneficial at first but could turn out to be a very unsuitable choice. Today, ZTA POWER will explain some valuable factors to consider when determining the power requirements for your diesel generator.

Assessing Your Power Requirements

Determining the size of a commercial diesel generator is not as simple as selecting one based on how much power you think you need. Several factors must be considered when identifying the appropriate power and type of diesel generator for your business needs. Depending on the type of business, power requirements may vary. Therefore, start by listing the absolutely essential equipment that needs power, including computers and lighting systems. Once you have the basics covered, add production equipment, construction machinery, electric tools, etc., that are not essential for normal business operations but would be convenient to have during a power outage. Additionally, ask your diesel generator manufacturer about the machine's runtime and whether they provide a warranty.

Different Types of Power Measurement Methods

You can determine the size of the commercial diesel generator you need through various methods, such as calculating your power consumption, considering the power factor, evaluating load capacity, etc.

Power Consumption Calculation

To calculate the power required for all the equipment, appliances, lighting, etc., in your business, you must multiply their voltage by their amperage. Then, multiply this value by the number of hours they will operate. This should be done for all equipment you want to power with the diesel generator. Using a clamp meter is the most accurate way to obtain real-time measurements and determine the load that will be placed on the diesel generator. The best way to use this method is with equipment that has motors, such as refrigerators, as motors produce fluctuations when cycling on and off. By connecting the clamp meter to the device and running it for about 15 minutes, you can accurately measure the average load on the diesel generator. The same process can be repeated for other devices by adding more meters until all equipment requiring power is measured. After calculating the total wattage, add 25% to account for any fluctuations.

Example:

A refrigerator running at 120V and 2.5A for 24 hours a day requires 120 x 2.5 x 24 = 7,200W or 7.2 kW per day.

Assessing Load Capacity Based on Your Power Consumption History

This method involves reviewing your bills from the previous few months and identifying the peak usage for each month. After determining the highest consumption point, add a 25% reserve capacity to it.

Calculating Full Load Capacity Based on Motor Usage

If you heavily use motors or need to sum multiple appliances, it is easier to calculate the total wattage required by adding the full load capacity of each item.

Step 1: List the electrical items operating on motors, in order of importance for power supply during an outage.

Step 2: Determine the wattage required to start the motors for the items listed in Step 1. (Essentially, the starting wattage is 3-5 times the running wattage for most motors.)

Step 3: Add the wattage of each item, starting from the largest motor to smaller motors and non-motor loads.

Step 4: From there, divide your total by 1,000 to get your kilowatt (kW) requirement, then add 25% of that total to reach your total wattage requirement.

Calculating Running and Starting Wattage

Wattage is used when a device or tool is running (running wattage). Then, wattage is used when the device or tool starts (starting wattage). Running wattage is the basic requirement for the continuous operation of a device. Starting wattage is needed to start and run the device. The difference between them can be significant.

Do not simply add up the running wattage listed on the devices, as the starting or surge wattage is typically three times the running wattage. In addition to the standard power requirements of an appliance or tool, there is an initial startup requirement. This surge lasts only a second or two but must be included in the total power calculation.

For items with electric motors, multiply the running wattage by three. The starting requirement for electric motors is higher than the running requirement. For items with computer chips, multiply the running wattage by 1.5.