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Removing rotational uncertainty

Joe Bush, Editor

05/01/2012

Tags: Test & Measurement

Topics: Test & Measurement

Megger’s new PSI410 phase sequence indicator enables the phase rotation of 3-phase supplies to be checked quickly, reliably and safely, thus eliminating the risk of the costly damage to equipment that can occur when supplies are incorrectly connected.

With a CAT IV 600V safety rating, the new PSI410 is suitable for use on all parts of LV installations. It uses a bi-colour LED display to show phase sequence - for clockwise phase rotation the LEDs show green and are illuminated in a clockwise sequence, whereas for anti-clockwise phase rotation the LEDs show red and are illuminated in an anti-clockwise sequence.

The apparent rotational speed of the display is not governed by the frequency of the supply. Instead, the speed has been chosen to make it easy to see the direction of rotation. As well as being visibly displayed, clockwise phase rotation is indicated audibly by a continuous tone and anti-clockwise rotation by a warbling tone.

To confirm the presence or absence of phases, three additional bi-colour LEDs are provided. These show green for phases that are present and have a voltage of at least 195V, and red for phases that are absent or have a lower voltage.

The indicators, which are supplied complete with a set of 830mm long fused test leads, together with probes and crocodile clips, need no batteries as they are powered from the supply under test.

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