How Do I Load A Generator Properly?

Loading a generator properly means ensuring the engine is working within its ideal performance range. Diesel generators operate most efficiently when running at 60 percent load or higher. At this level, the engine reaches the proper temperature for complete combustion, clean exhaust flow, and healthy aftertreatment performance.

To load a generator correctly:

1. Know your real kW output.
   A generator labeled in kVA only delivers about 80 percent of that rating in usable kW, and even less when switched to single-phase.

2. Match the generator size to the job.
   Choose a generator that will consistently operate between 60–80 percent of its available kW. Oversized generators run too lightly loaded, causing carbon buildup and wet stacking.

3. Avoid single-phase when possible.
   Switching to single-phase reduces capacity by roughly one-third. Even at full single-phase load, you may only reach about 60 percent of the engine’s real capability.

4. Monitor load during operation.
   Watch the controller display or use load profile data to ensure the generator is meeting the minimum load threshold. If the load fluctuates too low, consider pairing loads or selecting a smaller unit.

5. Maintain steady load whenever possible.
   Long periods of low load cool the exhaust and prevent proper regeneration in Tier 4 systems, leading to faults and downtime.

Proper loading keeps exhaust temperatures high enough to prevent carbon buildup, improves fuel efficiency, protects aftertreatment systems, and extends the generator’s life. With the right load and correct sizing, your generator will perform reliably and avoid unnecessary service issues.