To ensure that its pumps satisfy customer performance demands, ABS Production Wexford Ltd puts its pumps through vigorous testing procedures to verify specified performance criteria to meet international requirements. This enables the company to issue an appropriate performance compliance certificate. Tests previously performed manually are now automated resulting in a three fold increase in through put. Helping to achieve this is a variable voltage transformer from REO (UK).
To achieve certification, each pump is tested through its full range. Hydraulic performance measurements include pressure against the flow, efficiency against flow and power against the flow. Results are plotted against advertised data and must fall within specific tolerances in order to achieve certification.
Until recently, the whole testing process was a manual operation. However, a rapid increase in the number of pumps requiring certification, plus one particular range having to be tested to confirm compliance with industry standards, saw the time burden become unrealistic. Storage of associated paperwork also became an increasing problem.
To overcome these problems, an automatic testing procedure was developed. This involves mounting pumps in a test rig where appropriate diameter pipes are fitted using quick fit brackets. Pump operation is computer controlled and tests are pump specific with type and serial number logged. During the test, voltage is monitored whilst valve settings are electronically controlled permitting performance readings to be taken, logged and compared against pass / fail criteria.
With the pumps being exported all over the world, and therefore having to be run on different voltages and frequencies, an essential part of the new automated test system is a variable / fixed transformer combination from REO UK. The REO transformer runs off a 3 x 380V supply, with the fixed / variable combination being able to deliver any output voltage from zero to 700V, with a total power output of 182 kVA. This enables the test system to handle ABS's full range of pumps, rated from 1.3kW all the way up to a 20kW, at all the standard worldwide voltages.
The communication between the transformer and the computer, by means of a 0 - 20mA analogue signal, stabilizes the delivered voltage to ensure a valid certification test. This is because variations in voltage will affect the speed of the pump motor and impact on hydraulic performance, a function of impeller speed.
At the start of the test, for instance of a 460V 60Hz pump, the details of the pump are fed into the computer which then selects the correct setting on the transformer for 460 V and generates 60 Hz. Voltage fluctuations start to occur when the pump motor draws more power while running between one end of the test curve and the other. The computer, which monitors the voltage, will then give a feedback signal back to the transformer to tell it that the voltage has dropped and needs adjustment to ensure voltage stability.
For correct measurements to be taken at the start of any test, the REO transformer has also been designed with a soft start system which ramps up the voltage from zero to the operating voltage within a specific time, preset by the computer.
In the event of a problem on the test rig, an emergency stop button will immediately isolate the transformer plus all circuit breakers for protecting the cabling and the pumps that are local to the test rig. The fixed transformer also has separate primary and secondary windings which render the output "floating", making it completely safe. The only maintenance required by the transformer is periodic brush cleaning on an annual basis.
ABS Production Wexford has now installed another REO transformer to fulfill a similar role in its Research and Development department. During the testing of new pump designs, from an electrical standpoint, the voltage, three-phase currents and, from that, the input power are all monitored. From these values, power factor and hydraulic performance are calculated and then used to further refine a pump's design.
Chris Dawkins, formerly Head of the R&D Test Department at ABS Pumps has been impressed with the new system's performance, "The new automated test system with the REO transformer has increased throughput at the test rig by a factor of three. We were recommended to use REO by our local contractor and have not been disappointed. The level of service has been excellent, including them making the long trip over here to go through all our specifications, rather than trying to do it all over the phone.