Pump maker triples testing speed

A REO product story

Edited by the Engineeringtalk editorial team Dec 13, 2005

ABS Production Wexford has tripled the speed at which it can put its pumps through vigorous testing procedures to verify specified performance criteria to meet international requirements.

ABS Production Wexford has tripled the speed at which it can put its pumps through vigorous testing procedures to verify specified performance criteria to meet international requirements.

This lets the company issue an appropriate performance compliance certificate.

Tests previously performed manually are now automated resulting in a threefold increase in throughput.

Helping achieve this is a variable voltage transformer from REO.

To achieve certification, each pump is tested through its full range.

Hydraulic performance measurements include pressure against flow, efficiency against flow and power against flow.

Results are plotted against advertised data and must fall within specific tolerances 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 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 while 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.

The REO transformer runs off a 3 x 380V supply, with the fixed/variable combination able to deliver any output voltage from 0 to 700V, with a total power output of 182kVA.

This lets the test system handle ABS's full range of pumps, rated from 1.3 to 20kW, at all the standard worldwide voltages.

The communication between the transformer and the computer, via a 0-20mA analogue signal, stabilises 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 with.

say, a 460V 60Hz pump, the details of the pump are fed into the computer which selects the correct setting on the transformer for 460V and generates 60Hz.

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 give a feedback signal to the transformer to tell it the voltage has dropped and needs adjustment to ensure voltage stability.

For correct measurements to be taken at the start of any test, the transformer has a soft start system that ramps up the voltage from zero to the operating voltage within a specific time, preset by the computer.

If there is 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 safe.

The only maintenance required by the transformer is annual brush cleaning.

ABS has installed another transformer for a similar role in its research and development department.

During the testing of new pump designs, 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 refine a pump's design.