Synchronous vs Inverter Generators: Which One?

What a synchronous generator is

Synchronous describes the way an alternator makes electricity. In a synchronous generator, the alternator produces alternating current directly, and the frequency of that current follows the speed of the engine. The engine's governor holds the speed near a set point, so the output frequency stays in range while the load changes. It is the older and more common design in portable generators, and it is the design most listings describe when they say conventional or open frame. The machine is usually a simple circuit: engine, alternator, outlets.

The word synchronous appears rarely in consumer listings. Most titles use conventional, open frame, or just the watt figure. When a listing does not print the word inverter, the machine is usually a synchronous design. The listing gives you the design family, not a measured outcome. The maker's page states the frequency and voltage figures for the model, and those are the numbers to read when you compare portable generator listings.

What an inverter generator is

An inverter generator makes alternating current in two steps. The engine drives an alternator, the inverter electronics turn that current into direct current, and the electronics then turn it back into alternating current at the output. Because the electronics set the output frequency, the engine speed can rise and fall with the load instead of holding one speed. The design separates the engine's behaviour from the electricity that reaches the outlets.

The word inverter is a feature word in a title. It often appears first, as in inverter generator. On a listing it sits beside the watts figure, the fuel words and features such as electric start, RV ready outlets and a CO sensor. Those are the stated details the site compares. The maker's page states the frequency, voltage and output figures that the listing leaves out. Read the inverter generator guide for picks separated by stated details.

How the two designs differ as listing terms

The difference is the number of steps between the engine and the outlet. A synchronous generator sends the alternator's current straight to the outlets, so the engine speed sets the frequency and the governor must hold it. An inverter generator converts the current twice, so the electronics set the frequency and the engine speed can follow the load. That is the whole of the difference as a listing term.

The two design families do not map to a fixed wattage group. Small inverter listings and larger conventional listings both exist in the catalogue. The type word in the title tells you the design, and the watt figure tells you the magnitude. When you compare two listings, match the type word, the fuel words and the watts group before you read further. Running watts and starting watts explains how the title and the maker's page present the figures.

Why titles print one word or the other

A generator title is built from a short list of words: a type word, a fuel word, a watts figure and a few feature words. The type word is usually inverter or a word that says conventional, such as open frame. The seller prints the word that separates the product in the catalogue, and the same model can appear in several guides under different names.

When you see the word inverter, the title tells you the design family. When you do not see it, the machine is generally a synchronous design sold as a conventional or open frame set. The rest of the title, including the fuel and the feature words, reads the same way for both families.

What to read on the listing and the maker's page

On a listing, read the type word first, then the fuel words, the first watts figure and the feature words. The first watts figure in a title is usually the starting figure, and the running figure appears on the maker's page. The maker's page also states the frequency, the voltage and any feature the listing mentions by name, such as an RV ready outlet or a CO sensor.

This site compares generators on stated details from the catalogue. The site cannot tell you which design uses less fuel or holds a steadier voltage; the maker's page and the maker's support team answer those questions. For carbon monoxide guidance, follow the maker's manual and read the CPSC, CDC and EPA pages linked in the sources. Browse gasoline listings or dual fuel listings next.

What this site cannot say about the two designs

The catalogue states the type, the fuel and the watts figures. It does not state measured fuel use, runtime, noise or voltage stability. This article explains the listing words, and it stops there. The maker's page for a specific model is the place to read frequency, voltage and output figures.

For a buying decision, work with the stated details and the questions you would ask the maker. The site cannot rank one design family above the other on measured performance. The type word simply places the machine in a design family, and the guides separate picks by it.

Shopping by situation

For a camper or an RV owner, inverter listings appear often in the camping guide and the RV guide, and the type word is part of how the site separates picks. For home backup with a higher wattage figure, conventional open frame listings appear in the larger portable sets, and standby listings appear in the whole house guide. For a first generator, choose by the type word, the watts figure and the fuel words in the title, then read the maker's page before you buy.

What to pick for your situation

Questions

Is an inverter the same as a conventional generator?

No. The two words describe different ways of making electricity. A conventional generator sends the alternator's current straight to the outlets, while an inverter generator converts the current twice. A listing usually prints one word or the other, and the maker's page states the frequency and voltage figures for the model.

Do listings say synchronous on them?

Rarely. Consumer listings use conventional or open frame for synchronous designs, and inverter for the other family. The word synchronous appears mostly in technical descriptions on the maker's page or in an owner's manual.

Which design holds voltage more steadily?

The two families differ in how the output frequency is held. A synchronous generator ties frequency to engine speed, and an inverter generator sets frequency through its electronics. The maker's page states the frequency and voltage figures for a specific model, and the maker's support team answers questions about a particular machine.

Which one should a camper pick?

The camping guides on this site separate picks by type word, and inverter listings appear often in them. Read the stated details on the listing and the maker's page to match your rig's plug, and confirm the outlet type with the RV maker.

Why does the title show one watt figure and the maker's page show two?

Titles commonly print the starting watts figure, and maker's pages print both starting and running watts. Read both figures on the maker's page before comparing two listings.

Does a conventional listing work for home backup?

Conventional open frame listings appear in the larger portable sets, and standby listings appear in the whole house guide. Match the watts figure and the fuel words to your situation, and ask the maker and a licensed electrician about connecting a set to your home's wiring.

What does the word open frame mean on a listing?

Open frame describes the construction of a portable set, and it usually appears on conventional synchronous designs. It is a listing term, not a measured claim. The maker's page states the dimensions and weight for the model.