Skip to main content
Hongyi Electronics
Load Banks & Test Resistors for Generator/UPS Testing
Resistive Loads · Generator Commissioning · UPS Acceptance · Data-Center QA

Load Banks & Test Resistors for Generator/UPS Testing

Load banks apply controlled electrical load to generators (diesel, gas, hydrogen-ready), UPS systems and data-center power chains to verify performance under realistic conditions. NFPA 110 §8.4 mandates monthly 30-minute exercise of standby generators at ≥30% rated load — a load bank lets data centers run this test without dumping the load on production circuits. Hongyi supplies portable resistive load banks from 50 kW to 2.5 MW (single-trailer 800 kW typical) and stationary cabinets to 5 MW, with 1-step or stepped switching from 5% to 100% load. Voltage ratings 208 V to 13.8 kV, 50/60 Hz. Built per IEEE 115, IEC 60034-2-1 acceptance test methodologies. Cooling is forced-air (axial fans on top, ambient discharge); 0.95–1.0 power factor depending on R-only or R-L blend. Used by Cummins, Caterpillar, Kohler, Vertiv, Schneider field service teams worldwide.

Key Requirements

Key Requirements

  • Power range 50 kW–5 MW per cabinet/trailer; modular for higher totals
  • Voltage ratings 208 V / 415 V / 480 V / 690 V / 4.16 kV / 6.6 kV / 11 kV / 13.8 kV per IEC 60038
  • Stepped switching: 5%, 10%, 25% load increments + master ON/OFF + emergency stop
  • Continuous duty (S1) per IEC 60034-1 — must run hours, not pulses
  • Forced-air cooling with 70 dB(A) at 1 m, ambient -20°C to +50°C operation
  • Built-in metering (kW, kVA, V, A, Hz, PF) and Modbus/RS-485 for SCADA logging
How to Select

How to Select

  1. Match the highest generator/UPS rating you'll test, then add 25% margin (test transient overload)
  2. Pick voltage class one step above your equipment (480 V test → 600 V-rated load bank)
  3. Choose stepped resolution that resolves your acceptance criteria (typically 5% steps)
  4. For monthly NFPA 110 testing, prefer resistive-only (PF=1) — simpler, no kVAR variability
  5. For real-load simulation in data centers, choose RL load bank (PF=0.8 lag) to match server profile
  6. If outdoor or trailer-mount, specify NEMA 3R / IP55 enclosure with hinged panels for service
Recommended Products

Recommended Products

Resistor Boxes
Resistor Box / Cabinet

Resistor Boxes

Integrated resistor cabinet solutions for industrial braking and energy dissipation

View product family
High-Power Resistors
High Power Resistor

High-Power Resistors

Industrial-grade braking and discharge solutions covering 50W ~ 100kW

View product family
Aluminum Housed Resistors
Aluminum Housed Resistor

Aluminum Housed Resistors

Aluminum-housed resistors with superior heat dissipation — ideal for inverters, servo drives and other high-power applications

View product family
Related Articles

Related Articles

High-power corrugated braking resistor for industrial VFD systems

How to Choose a High-Power Braking Resistor — A 2026 Engineer's Guide

Five common sizing mistakes, the formulas you actually need (with worked example), and how to read derating curves correctly.

Read article
Aluminum housed, cement and wirewound resistors side by side — Hongyi Electronics

Aluminum Housed vs Cement vs Wirewound Resistors — Complete Comparison

Which family fits your application? A 12-parameter table, decision flowchart, and three real-world case studies.

Read article

Frequently asked questions

How big a load bank do I need to test a 2 MW diesel generator?
Pick at least 2 MW continuous resistive — ideally 2.5 MW so you can test the generator at 110% nameplate during the IEEE 115 acceptance overload test. Most field tests use a 2 MW trailer-mount unit (typical dimensions 5 × 2.5 × 3 m, 6000 kg) at 480 V or 4.16 kV. Verify that the genset's circuit breaker, cable size, and load bank input class all match — a mismatch is the #1 cause of canceled commissioning visits.
What's the difference between a resistive-only and a resistive-reactive load bank?
Resistive-only (PF=1) tests engine power output and excitation system but doesn't represent real-world inductive loads (motors, transformers, server power supplies). RL load banks add inductors to give PF=0.8 lagging, the IEEE 115 standard test condition for AVR/voltage regulation performance. For NFPA 110 monthly exercises, R-only is fine. For commissioning sign-off and warranty acceptance, you typically need RL.
Can the load bank be controlled remotely from a SCADA or laptop?
Yes — our standard option includes Modbus RTU over RS-485 plus optional Modbus TCP over Ethernet. Step relays, master contactor and emergency stop are all writable; metering (kW, kV, A, kVA, kVAR, Hz, PF, kWh) is readable for trend logging. We supply a Windows test app and ICD documentation for integration. Some customers integrate with HP iLO or Vertiv data-center BMS for fully automated weekly tests.
How is heat from a 2 MW load bank discharged safely?
A 2 MW resistive load creates 2 MW of heat — enough to warm 100 m³ of air by 60°C in one minute. Cooling is forced air discharged vertically through axial fans (typical 60–80 m³/s flow), keeping discharge plume above 8 m. Site safety requires 5 m perimeter clearance, no flammables in discharge cone, and approval of nearby rooftop equipment. For sensitive sites we offer water-cooled load banks (heat to a sacrificial chiller loop) at 2× cost.
Sample Request

Sample Request

Standard samples are provided free of charge in reasonable quantities (shipped within 2–3 business days). Custom samples are delivered within 2–4 weeks. Please use the form on the right to tell us:

  • Company and contact details
  • Target part number or key specs (power / resistance / package)
  • Application scenario and estimated annual volume
  • Shipping address and expected delivery date
📧 You can also email us directly at info@resistor-factory.com / 13650089870
Inquiry

Online Inquiry

By submitting you agree to our Privacy Policy