Dingbo Product Page

HOW TO CHOOSE A USED DIESEL GENERATOR

THAT IS RIGHT FOR YOU

When it comes to selecting a used diesel generator set, you must consider various factors to ensure you make the right choice for your needs. There are important decisions to make regarding which used diesel generator to purchase, where to install it, and how to do so effectively. In this article, we will discuss key aspects of the selection process. Choosing the right generator doesn't have to be a daunting task if you take the time to evaluate your requirements and have a fundamental understanding of generator types. Remember, the sales engineering team at US Power is here to support you throughout the generator selection, sizing, and installation process. Familiarizing yourself with essential terminology and having a basic comprehension of the different types of generator sets will be beneficial. Please refer to our glossary of terms as necessary.

STAND-BY OR PRIME?
The first step is to determine whether you need stand-by or prime power. In simple terms, prime power is necessary when you lack any other power source, while a stand-by diesel generator acts as a backup to the regular utility power. Understanding this distinction will assist in selecting the appropriate generator size, as diesel generator kW output experiences a de-rating of about 20% for prime usage.

GENERATOR TYPES & FEATURES
Generator sets can produce either single-phase or three-phase power. If your motors are 5hp or smaller, opt for a single-phase set. On the other hand, three-phase power is more suitable for larger motors during startup and operation. Typically, homeowners will need single-phase, while commercial or industrial settings often require three-phase power. Three-phase generators may produce 120/208 or 277/480 volts, while single-phase sets typically provide 120 or 120/240. Utilize lower voltage for household appliances and higher voltage for motors, heaters, stoves, and dryers.

GAS OR DIESEL?
Our recommendation is to choose diesel generators for their longevity (over 30,000 hours) and lower operating costs due to reduced maintenance and fuel efficiency. Modern diesel generators are generally more durable, quieter, and need less maintenance than comparable gas (natural gas or liquid propane) generators. Furthermore, fuel costs per kW produced with diesel generators are typically 30% to 50% less than those of gas generators. Diesel generators showcase their ruggedness due to running cooler and being constructed with heavier-duty engine blocks. For example, water-cooled diesel models usually operate on average 12,000 to 30,000 hours before requiring major maintenance, whereas similar gas models only last 6,000 to 10,000 hours before a rebuild is necessary. In contrast, air-cooled gas units tend to be replaced at 500 to 1,000 hours. Since gas engines burn hotter, their lifespan is notably shorter than that of diesel engines.

OPERATING SPEED
Electrical equipment operates at fixed frequency: 60 Hertz (Hz) in the US and Canada, while Europe and Australia use 50 Hertz. The frequency output of a generator hinges on a stable engine speed. To generate 60 Hz electricity, most engines run at either 1800 or 3600 RPM. Each option has its advantages and downsides. The more common 1800 RPM, four-pole sets offer an excellent balance of noise, efficiency, cost, and engine lifespan. Conversely, 3600 RPM, two-pole sets are lighter and more suitable for portable, light-duty applications. Think of it like driving your car at 120 mph versus 60 mph – driving at 60 mph in a well-maintained vehicle will extend its lifespan, create less noise, and require lighter maintenance. Most 1800 RPM units feature twin-cylinder air-cooled engines, while water-cooled 1800 RPM generators exhibit engine types found in forklifts and tractors. While these water-cooled diesel generators are pricier upfront, they do provide longer operational life, fewer maintenance issues, and enhanced fuel efficiency. Ultimately, your choice will depend on your budget and facility needs.

FEATURES & BENEFITS TO CONSIDER: THE ENGINE
For optimal durability and quiet operation, we suggest selecting four-cycle, liquid-cooled, industrial-duty diesel engines. Contrary to air-cooled engines that require significant airflow and may necessitate ducting, liquid-cooled models operate more quietly and provide superior temperature control, extending product lifespan. You can save time servicing your generator and money on new filters by choosing a unit with a large, integral air cleaner featuring a replaceable filter element and a critical muffler integrated into the exhaust manifold, negating the need for an additional muffler.

In a DC electrical system, the standard 12-volt configuration should encompass a starter motor and battery charging alternator, alongside a solid-state voltage regulator. Diesel units ought to include a pre-heat switch, start/stop switch, and safety shutdown system to safeguard the engine against oil pressure loss. A generator must also consist of overspeed, overcrank, and high water temperature alarms connected to the DC system circuit breaker.

GENERATOR END
Your AC generator should incorporate a 4-pole revolving field and an automatic voltage regulator that guarantees 'clean' power, critical for backing up computer systems or delicate electronic equipment. Conventional utility power tends to provide +/- 5% voltage regulation, with many 1800 RPM models boasting a rating of +/- 2%. This is something to confirm when assessing individual diesel generators.

ENGINE ACCESSORIES: Sound Attenuation, Filters, and Block Heaters
Once you've decided on the appropriate generator size, compile a list of essential optional and installation equipment. For noise control, we recommend a residential (not industrial-grade) muffler, as numerous cities impose regulations demanding sound-attenuated enclosures (70dba or quieter). A good primary fuel filter or water separator is crucial for protecting your engine's fuel system. Stand-by sets may also need a block heater to maintain the coolant/water mixture at an adequate temperature for easier starts, and a battery charger is always a smart inclusion.

AC SWITCHGEAR AND CONTROLS
Every generator setup necessitates a circuit breaker and distribution panel. The circuit breaker is essential for safeguarding the generator from short circuits and unbalanced electrical loads, while the distribution panel helps manage and route connected loads and includes relevant circuit breakers for protection. The complexity of switchgear can vary widely, as can its cost. Most applications generally only need a base model automatic transfer switch equipped with a digital panel and weekly exercise features, while certain facilities may require soft-load and paralleling switchgear. A balanced approach combined with advice from a knowledgeable electrical specialist is key in these scenarios.

Please keep in mind that US POWER & ENVIRONMENT is a turnkey Power Solutions Specialist, ready to address all your generator needs, from 3 Mega Watt units catering to industrial customers seeking heavy-duty standby generators to residential models. We offer high-quality products that are competitively priced!

 

Key Factors to Consider Before Installing a Generator