Powering Industries for 50+ Years
Load Bank Testing for Industrial & Commercial Generators
Generator Sales, Service, & Rentals
Prove your generator under real load, not just at idle.
Generator Source performs professional load bank tests to verify that your standby or prime power system can deliver rated power safely and reliably when it matters most.
What Is a Load Bank Test?
A load bank safely applies a controlled, incremental electrical load to your generator and measures performance at each step. Our technicians simulate real-world conditions, typically at 25%, 50%, 75%, and 80%, to verify the unit’s capability, stability, and cooling capacity over time.
Why Load Bank Testing Matters
A generator that starts is not the same as a generator that performs.
- Power Rating: Confirms the unit can produce rated kW and maintain voltage and frequency stability under real demand.
- Wet Stacking: Prevents wet stacking in diesel units by burning off unburned fuel and carbon.
- Hidden Issues: Reveals hidden issues (cooling, fueling, controls) before an outage.
- Compliance: Documents performance for audits, insurers, and compliance programs.
What We Test & Verify
- Electrical performance: voltage, frequency (Hz), phase balance, power factor
- Output stability: response to step-load changes, transient recovery
- Thermal behavior: exhaust temps by cylinder (IR checks), coolant temps, oil temps
- Mechanical health: vibrations, abnormal noise, leaks, belt condition
- Controls & protection: alarms, shutdowns, governor/AVR response, safeties
- Emissions health (diesel): soot and visible smoke reduction after full-load operation
- Deliverables: a signed Load Bank Report with all readings, observations, pass/fail notes, and recommendations.
Our Load Bank Testing Process
- Pre-test inspection: Visual checks, fluid levels, belts/hoses, battery and starter condition, fuel supply, and airflow.
- Warm-up & baseline: Verify no-load voltage/frequency, governor and AVR baseline.
- Step loading: Apply 25% → 50% → 75% → 80% load; hold each stage to stabilize and log readings.
- Sustained full-load run: Prove continuous power delivery; monitor cooling/exhaust temps and engine response.
- Step unload & recovery: Observe voltage/frequency recovery and protective device behavior.
- Post-test inspection: Re-check leaks, connections, codes/alarms; review results with your team.
- Report & recommendations: Detailed documentation plus prioritized action items (e.g., cooling service, fuel polishing,
Common Issues a Load Bank Test Catches Early
Underfrequency/Undervoltage
Underfrequency/undervoltage under load (governor/AVR tuning needed)
Fuel Starvation
Fuel starvation from clogged filters or contaminated fuel
Wet Stacking
Wet stacking from chronic low-load operation
Load Bank Pass/Fail Criteria
- Maintain rated kW at specified voltage and frequency with acceptable droop limits
- Hold phase balance within tolerance
- Sustain full-load temps without alarms or shutdowns
- Recover smoothly from step-load changes
- Failures trigger a corrective action plan, our technicians outline exactly what to fix and how urgent it is
Types of Load Banks
Resistive
Resistive (kW): simulates real power (most common for diesel and NG sets)
Reactive
Reactive (kVAR): evaluates alternator/AVR behavior for motor and transformer loads
Portable Trailer-Mounted
Portable trailer-mounted units: rapid deployment to your site
Integrated/Load-Bank-Equipped Mobiles
Integrated/load-bank-equipped mobiles: ideal for rental fleets and Tier 4 compliance
Recommended Load Bank Frequency
Annual
Annually for most standby and prime generator applications.
Ensure dependable performance with a yearly test that verifies output, stability, and readiness.
Semi-Annual
Semi-annually for mission-critical sites or harsh environments.
Extra assurance for hospitals, data centers, and facilities exposed to extreme weather or heavy demand.
Post-Repair or Idle
After major repairs, control retrofits, or long idle periods.
Confirm that upgrades or long downtime haven’t compromised performance.
Seasonal
Before hurricane/winter seasons or planned utility shutdowns.
Prove your system is ready before high-risk outage periods or scheduled maintenance events.
Complementary Generator Maintenance Services
Whether you need routine maintenance, emergency repairs, or custom modifications, our EGSA-certified technicians have you covered. Here’s how we keep your power generation systems running smoothly:
Automatic Transfer Switch (ATS) Services
- Expert ATS sizing and installation assistance
- Site preparation and planning for seamless integration
- Customized solutions for various backup power scenarios
Control Panel Installations & Upgrades
- Implement advanced monitoring and control systems
- Compatible with major brands: Deep Sea Electronics, Woodward Controllers, Caterpillar EMCP, Cummins Power Command
- Enhance remote monitoring, load sharing, and peak shaving capabilities
Custom Generator Fabrication
- Skilled fabricators for unique power generation projects
- Customized trailers, enclosures, and specialized equipment
- Turn your power generation concept into reality
Generator Battery Services (outside of scheduled PM)
- Comprehensive battery testing and replacements
- Partnerships with leading battery suppliers
- Ensure reliable starts and consistent performance
Generator Frequency Conversions
- Specialized 60 Hz to 50 Hz conversions for international operations
- Engine modifications and third-party frequency converter installations
- Customized solutions for global power requirements
Generator Oil Analysis
- On-site and lab-partnered oil testing
- Rapid results for informed maintenance decisions
- Proactive approach to generator health and longevity
Generator Painting and Aesthetics
- High-quality painting services for generator refurbishment
- Enhance the appearance of your power equipment
- Protect your generator from environmental factors
Industrial Generator System Sizing
- On-site analysis and customized power planning
- Expert consultations for optimal generator sizing
- Engineering services for complex power requirements
Load Bank Testing for Generators (outside of scheduled PM)
- Generator phase conversions
- Tailored solutions to meet changing power distribution needs
- Complimentary testing for all generator sales
- On-site load bank testing services for larger industrial generators
- Ensure optimal performance and reliability under various load conditions
Voltage ChangesControl Panel Installations & Upgrades
- Convert between 480V and 277V configurations
- Hourly rate service available for all customers
- Expert assessment of generator reconfiguration possibilities
Voltage Regulator Replacements
- Diagnostics and replacement for malfunctioning regulators
- Upgrades to meet specific voltage regulation requirements
- Expertise in both self-contained and separate regulator systems
Other Services
- Paralleling configurations for increased power capacity
- Transformer installation and configuration
- On-site troubleshooting for rapid issue resolution
- Customized planned maintenance programs
Load Bank Videos & More
Still have questions or looking for more information?
Generator Source specializes in low-hour, used, new, and surplus generator sets. We have a wide variety of generator sizes and models to fit any project. We are not a broker, we own what we sell.
Call us today (877-866-6895) or click Contact Us to be connected with one of our experienced sales reps.
We have 350+ generators in stock and ready to ship!
