Portable dynamic balancing is required for turbines, fans, and propellers and other rotating components in machinery that cannot be removed from the field and brought to a balancing facility. While portable balancing is similar in process to static dynamic balancing, it is much more difficult to undertake because it often has to be conducted under less than ideal conditions that are beyond the control of the portable dynamic balancing technicians.
Dynamic balancing equipment in situ (where it is installed) is much more difficult where system resonance exists. Knowing how to identify a system that is in resonance is an important part of a balancing technician’s job. Most portable balancing electronics use two-channel or four-channel data acquisition, and there are telltale signs in the raw balancing data. The trigger for making a call that a system is in resonance usually starts with the technician having difficulty making balance corrections that produce efficient results.
All types of rotating machinery need to be balanced and checked regularly, including blowers, fans, generators, and much more. Some types of equipment that may need portable balancing include power plants, utilities, mills and other manufacturing facilities.
A perfect example of system resonance we’ve encountered was a US Navy warship powered by two Rolls Royce 50,000 hp MT30 gas turbines driving into a combiner gearbox with a driveshaft coupled to the rear of the turbine. The combiner mixes power from two 15,000 hp diesel engines with turbine power. The ship is designed to cruise on diesel power and the Turbines can be off or running a “core idle”. Core idle is 2400 rpm. Full power is 3500 to 3600 rpm.
HI-TEK had been tasked to trim balance the output shafts that are connected to the turbine engines. The shafts are 24” diameter using Bibby Turboflex disc couplings. The shafts are about 20 feet long. Only the front of the shaft where it meets the turbine is corrected. No one has seen the need to do more than this. HI-TEK has serviced five ships with ten turbines in this configuration.
This gives you some idea of the wide range of rotating systems that we’re often called on to balance out in the field. That’s why we offer complete portable dynamic balancing services at customers’ facilities for those hard-to-service systems and components including:
- Roof-top mounted machinery
- Difficult-to-ship items
- Machinery requiring normal operating conditions
- Special installations
Our field service technicians and portable balancing, testing, and analysis equipment, including Commtest vBSeriesR vibration analyzers, are ready to travel just about anywhere to service virtually any rotating component and system.