Power Products · · 3 min read
Diesel Generator Buying Guide: How to Choose the Right kVA
Sizing, fuel, noise, emission norms and service: what to check before you buy a diesel generator for your business.
This diesel generator buying guide explains how to choose the right DG set for a home, office, factory or site. The most important decision is the size in kVA; getting it wrong means either wasted money or a generator that trips when you need it most.
Step 1: List the loads
Write down every equipment the generator must run: lights, fans, air conditioners, computers, pumps, lifts and machines. Note the running power of each in kW or watts.
Step 2: Allow for starting current
Motors in pumps, compressors, lifts and air conditioners draw several times their running current for a moment when they start. The generator must handle these peaks, especially if several motors can start together.
Step 3: Convert kW to kVA
Generators are rated in kVA. For most commercial loads, divide total kW by a power factor of 0.8 to get kVA. Then add a margin, commonly around 20 to 25 percent, for future growth and to avoid running the generator at full load all the time.
Step 4: Choose single-phase or three-phase
Small homes and shops may need single-phase power. Offices, factories and buildings with three-phase equipment need a three-phase generator.
Silent vs open diesel generators
Silent (acoustic enclosure) generators are designed for low noise and are the standard choice for offices, residences and urban sites. Open sets are used in industrial areas where noise is less of a concern.
Emission norms
In India, new diesel generator sets must meet the current CPCB emission norms (CPCB IV+ for the applicable power ratings). Buy only compliant sets from authorised suppliers.
Automatic changeover
An AMF (automatic mains failure) panel starts the generator and switches the load when mains power fails, then switches back when it returns.
Fuel, installation and service
Check fuel consumption at typical load, tank capacity and runtime. Plan a ventilated location with proper exhaust, earthing and foundation. Choose a supplier who offers installation, commissioning and regular maintenance.
JSK Infosolutions supplies diesel generators, stabilizers, UPS and solar systems, with load assessment, installation and service support.
Frequently asked questions
How do I calculate generator size in kVA?
Add up the running load in kW, allow for motor starting currents, divide by a power factor of 0.8 for kVA and add a margin of around 20 to 25 percent.
What is a silent diesel generator?
It is a DG set inside an acoustic enclosure that reduces noise, making it suitable for offices, homes and urban sites.
What is an AMF panel?
An automatic mains failure panel starts the generator and transfers the load automatically when mains power fails, and switches back when it returns.