A Buyer’s Guide to Purchasing a Diesel Generator

Congratulations, you’ve done your research and concluded that a diesel generator is right for you. You already know that this decision will result in the need for a smaller engine than a natural gas generator requires, thereby lowering your acquisition cost. You also know that you’ll enjoy a long lifespan with a diesel generator (upwards of 20,000 hours, prior to an overhaul) lower maintenance costs, greater fuel efficiency and faster response time.

Before you pat yourself on the back, however, there are some steps you should take to ensure the diesel generator you are purchasing is the right one for your particular needs. The following is a buyer’s procedural for a diesel generator purchase. Ask yourself these important questions before making a diesel generator investment.

1. What type of power do I require?
   Is your diesel generator going to be your prime power source or just an emergency / backup to traditional commercial power? This is an important first question to ask yourself since it will play into the kilowatt (kW) output requirement you will need.
   
   
2. How can I determine the kW output that’s right for me?
   If you are already an existing facility, your current electricity supplier can help you in this regard. When contacting them, ask them specifically for a 12-month peak and 12-month average kW load report. Armed with this information, it’s a simple matter of multiplication to determine your required kW output. Diesel generators should be sized at 75% of your peak load for optimum life expectancy.
   
   
3. What if I don’t currently have an electricity supplier or this is for a new building or expansion?
   An electrical engineer should calculate your expected kW loads.
   
   
4. What type of machinery will I be powering with my diesel generator?
   Your power backup requirements will determine the generator capacity called for. Will you be powering one small piece of equipment or several large ones simultaneously? The answers to this question will determine whether you need a single-phase generator (1/60/120/240V for most domestic and small business needs) or a three-phase generator (3/60/120/208, 3/60/120/240V or 3/60/277/480V, with 480V being most common, for heavy-duty motors and larger appliances). Higher-voltage diesel generator options like 4160V and 12470V are also available for the most demanding power situations.
   
   5. What other information is required to get started?
   If you are installing a typical building emergency back-up generator system you will need an automatic transfer switch as required by the National Electric Code for all permanent installations. You will need to find out and provide the incoming amps at your electric meter. This information will be needed to size the automatic transfer switch, the heart of your system, that monitors the utility for power outages and brings the generator online as required.

 

For more details on purchasing a diesel generator set, contact an Aaron Equipment’s generator specialist at 630-350-2200.