GENERATORS and LOAD BANKS FOR RENT

Generator Rentals


A continuous source of electrical power is critical to keep a facility operational. Our generator rental fleet has the right sized generator that can meet your requirements for emergency, temporary or back up power.
Our experienced service staff can assist you with any questions you have regarding the type of generator rental to meet your requirements. Our generators, and cooling rental equipment, is ready to be delivered to your location. We provide reliable service to a variety of industries. Generator rental solutions available 24/7.
Why Load Bank Test?

Load banking is a essential requirement to ensure that generator owners enjoy the full potential of their emergency backup power equipment and that it will perform as expected when called into service. Since emergency generators must be sized to accommodate the full startup load of a facility, ideally they are sized above the normal operating load if a load management system is not in place.

Generators are ideally sized as much as 30 percent over the kW rating of a facility to accommodate the surge of the building and equipment startup load. This situation creates a challenge with diesel powered generators. Conditions such as wet stacking and carbon buildup in combustion chambers, injector nozzles, piston rings, turbo chargers, exhaust piping and silencers can develop. Wet stacking is best described as unburned fuel that accumulates in diesel exhaust. It can be detected by black seepage around exhaust connections or continuous black exhaust from the stack after warm up. Exhaust gas temperature of 275 degrees Fahrenheit must be maintained to avoid wet stacking . With the increasing awareness of exhaust pollution, regular loadbanking is an important contribution on the generator owner's part to minimize exhaust pollution.

Wet stacking is common when diesel engines operate for extended periods of time with little or no load applied. To operate at peak efficiency, the engine must be able to provide the proper ratio of fuel and air and maintain the right temperature to burn that fuel completely. EPA requirements have resulted in dramatic improvements in engine design while the use of electronic controls has resulted in increased performance.

Every client should require load bank testing when commissioning an emergency power system to ensure proper installation, adequate cooling at ambient temperature, sufficient fuel delivery, and proper load transfer.

To test performance, load bank testing should be performed annually (for a minimum of two hours) for standby applications. During weekly exercises, the engine will not reach manufacturer's recommended operating temperatures. The National Fire Protection Association (NFPA 110) has established the standards for monthly maintenance and operation for standby generators that states, "Generators should be exercised monthly at 30 percent of the nameplate rating or loaded to the minimum engine exhaust temperature recommended by the engine manufacturer."

Planning

Load banking can create unexpected results. In many cases, the engine has not been tested to its capacity since the manufacturer's testing at the factory. If regular load banking was not instituted as part of a preventive maintenance plan, then the older the engine, the greater the risk of operational breakdown during testing. As a surgeon would review the potential consequences with his patient prior to an operation, it is important that you review the worst case events with your client prior to subjecting their facility to the potential risks of generator failure during a test. Test results will reflect the level of neglect or underutilization of the generator system.

The load should be disconnected from the generator while testing to prevent overloading the generator. For this reason, life support and mission critical clients need to be advised of the load bank test, and staff must be notified in the event of a loss of power. Backup generators should be recommended where a blackout is not an option for the facility. Testing should be scheduled during the most favorable time of the day, week and month when interruption would be most manageable. Be aware of any local Environmental Protection regulations.

Methods

There are two methods for load banking generators: resistive testing and reactive testing, with resistive load banking being the most common. The resistive method, which measures kW, but not kVA at the rated power factor, is ideal for testing the engine cooling system, exhaust system and the fuel delivery system. Reactive testing is a generator specific kVA test typically performed at the factory.

Observations

1. If the exhaust has not cleared (smoke-free) during the test period, engine repair will most likely be required. Extensive smoke is most often caused by rings that have never seated properly, a fuel pump that needs to be rebuilt or bad fuel.

2. If the temperature is not within the manufacturer's recommended range, the cooling system may need to be flushed to remove any restriction, or there could be a faulty thermostat or defective water pump.

3. If the oil pressure drops below the manufacturer's recommended range, the oil pump may need to be rebuilt or low pressure may be an indication of excessive engine wear that could signal the need for an engine overhaul.



Documentation

Ideally a digital recorder should be connected to chart frequency, voltage and amperage, and document in one-second sampling. This information should be downloaded to graph a detailed performance report. Engine oil pressure and temperature should be documented at 25, 50, 75 and 100 percent of the nameplate rating of the generator.

Conclusion

Load bank testing should not be considered an option, but rather a critical element of your emergency preparedness plan. If you are the maintenance provider, consider it your responsibility to recommend load banking to your client. As a generator owner, make sure this is included as part of your annual maintenance plan. There is no better way to have the peace of mind that you are prepared when the lights go out!