When you're looking to buy a diesel generator, you’ll come across terms like kW, kVA, and power factor. If you’re not an electrician or engineer, these terms can be confusing. But don’t worry—this guide breaks them down into simple language so you can understand what they mean and why they matter.
WHAT DO DIESEL GENERATORS DO?
Diesel generators are machines that produce electricity. They’re commonly used for backup power during blackouts or in areas where access to the power grid is limited or unavailable. Whether it’s a hospital, factory, construction site, or even a large event, having a generator can keep things running smoothly when the main power supply is down.
Whether you’re considering backup power generators for homes, onsite energy generators, or industrial generators for a commercial facility, understanding the specifications is key to making the right decision.
BREAKING DOWN THE BASICS
1. What is kW (Kilowatt)?
kW stands for kilowatt, and it tells you how much usable power a generator can provide. Think of it as the amount of electricity you’re actually getting to run your equipment—like lights, fridges, computers, or machinery.
If your generator is rated at 100 kW, it means it can supply 100 kilowatts of real power to your devices. This is the number you really care about when figuring out how many and what kinds of machines you can power—whether it’s for a generator for home use or a commercial generator.
2. What is kVA (Kilovolt-Amperes)?
kVA stands for kilovolt-amperes and is a measurement of apparent power. This includes both the usable power (kW) and the power that’s lost along the way due to inefficiencies.
Think of it like pouring a drink into a glass and spilling some—kVA includes the drink that actually made it into the glass (kW) and the part that got spilled.
So, a 125 kVA generator might only give you 100 kW of usable power. This matters a lot when comparing options from generator companies or browsing through listings for a generator for sale near me.
3. What is the Power Factor?
The power factor is a number that shows how efficiently the generator is converting kVA into usable kW. It's usually shown as a decimal like 0.8 (or 80%).
Formula:
kW = kVA × Power Factor
For most diesel generators, the power factor is 0.8.
So, if a generator is rated at 100 kVA, then the actual usable power is:
100 kVA × 0.8 = 80 kW
In other words, only 80% of the total power can actually be used to run your equipment.
WHY THIS MATTERS WHEN CHOOSING A GENERATOR
When picking a generator, you need to make sure it can handle everything you want to power. This means:
· Adding up the power requirements of all your equipment (in kW)
· Choosing a generator with a high enough kW rating to support that load
· Looking at both the kW and kVA ratings to make sure you're not overloading it
Whether you’re looking at home power generators or commercial generators for a business, this understanding can help you avoid costly mistakes.
COMMON GENERATOR LABELS AND WHAT THEY MEAN
Generators usually have a plate or sticker that lists their power ratings. Here’s what you’ll typically see:
· kW Rating: The maximum real power it can supply
· kVA Rating: The total apparent power it can produce
· Power Factor: Usually 0.8 unless otherwise specified
Some labels will also list two types of ratings:
· Prime Power: For situations where the generator will be used regularly or continuously
· Standby Power: For occasional use during power outages (this rating is typically higher than prime)
Understanding these specs will help you ask the right questions when contacting generator companies or searching for a generator for sale near me.
WHAT LIMITS A GENERATOR’S OUTPUT?
1. The Engine (kW Limit)
· The engine drives the generator, and it has a maximum amount of work it can do. This sets the limit for how much real power (kW) you can get out of it.
· Trying to use more power than the engine can handle can cause it to overheat or wear out quickly.
2. The Alternator or Windings (kVA Limit)
· This part of the generator controls how much total power (kVA) can move through the system.
· If you try to draw more than the alternator is rated for, it can overheat and shut down or get damaged.
WHAT’S THE DEAL WITH LEADING AND LAGGING POWER?
This part can sound technical, but here’s a simple way to look at it:
· Lagging Power Factor: Happens when the electrical load is mainly motors or transformers. This is the most common type and is usually no problem for generators.
· Leading Power Factor: Happens with capacitive loads like large banks of batteries or capacitor banks (used in some industrial or specialized onsite energy generator setups). Can cause voltage issues and may even cause your generator to shut down as a safety precaution.
Unless you're powering specialized equipment, you usually don’t need to worry much about leading power factor loads.
FINAL THOUGHTS: PICKING THE RIGHT GENERATOR
Choosing the right diesel generator is about more than just picking a big number. You want one that:
· Can handle the real power your equipment needs (in kW)
· Doesn’t exceed the total power limits (kVA)
· Works efficiently (check the power factor)
Whether you’re outfitting a business with industrial generators, upgrading home power generators, or searching online for a generator for sale near me, understanding these specs ensures you get a reliable, efficient power solution.
If you’re unsure, talk to us. At Masterpower, we’re here to make that process easier. Our team would be happy to answer your questions and guide you through choosing the right generator for your needs—whether it’s for backup power generators for homes, commercial use, or onsite energy solutions.