Electrical Testing

Reflective Surge Oscillograph (RSO)

RSO is a useful electrical test used on Generator Rotors where the windings are symmetrical predominantly 2 pole turbogenerators. Comparison of two reflected signals on either pole of a 2 pole winding can determine its continuity and location of possible interturn faults.

Tan Delta Winding Tests

Tan Delta Winding Test will determine the state of the insulation on a High Voltage winding and it’s ability to maintain a charge. The individual & combined phases can be tested during routine maintenance and results compared thus instulation state can be assessed.

Flash Testing

Flash Testing evaluates whether the electric insulation section of an electric motor or generator has sufficient dielectric strength for the working voltage (sometimes known as dielectric withstand or hipot test). This test is applied at varying levels dependant on the age and service of the machine and not recommended for older windings.

On Line Rotor Tests (IMCA)

Induction Motor Current Analyser (IMCA) is a test that completes a spectrical analysis of a Induction Motors supply current to test for cracked rotor bars while the machine is running in service.

Providing that the design of the Rotor and number of bars is known  then electrical defects, such as cracked rotor bars or shorting ring can be detected.

Flux Testing for Core Integrity

During the Rewind process, of  a generator or motor, the Stator Core requires to be stripped of  all the old coils leaving bare core laminations. During the actual failure the core maybe damaged resulting in shorts  between the core laminations thus causing “hotspots” especially in the teeth and inner bore areas of the stator.  A Core flux test using HV cables wrapped round the core and energised to electrically saturate the core allows a thermal image survey to be completed and areas of concern identified. Subsequent the core can be etched or restacked to eradicate these hot spots.

Insulation Resistance/Polarisation Index

The Polarization Index (PI) Test provides an Indication of the degree of contamination and moisture of the insulation on a High Voltage Winding. Utilising a HV DC Insulation Tester the test can be used as a comparative tool or as a standalone assessment of a High Voltage Winding condition. Working to National & International Standards the winding can be assessed and customers advised of required further works

Portable Appliance Testing (PAT)

Accessing customer sites and using equipment is only possible if the electrical devices have been PAT tested in advance. This service is offered both externally & internally to provide approved equipment.

Mobile Diagnostic Off-line VLF ‘Withstand’ and Tan Delta Testing Services

RE Field Services Ltd. is expanding its comprehensive electrical test services by introducing Very Low Frequency (VLF) AC ‘Hi-pot’ and Tan Delta (TD) diagnostic testing in accordance with internationally recognised IEEE 400.2 and IEEE 433-2009 standards. Our new, highly portable 60 kV rated VLF off-line HV diagnostic test set enables us to detect insulation problems at installation, commissioning and maintenance testing stages on land and subsea MV cables rated up to 33 kV and rotating machines rated up to 11kV. Testing with RE Field Services VLF power supply is a perfect marriage of DC ‘Hi-pot’ test set portability and AC voltage stress distribution across insulation similar to real operating conditions rotating machines and MV power cables are experiencing during normal service life.