Certain types of drives should never be rotated in the wrong direction. In such cases, the temporary hookup or trial method, having a fifty-fifty chance of being wrong, can do serious harm.
The Motor and Phase Rotation Tester provides a positive way toidentify the leads of a disconnected polyphase
motor; it also identifies true phase sequence of energized 60-Hertz ac power lines up to 600 volts. Both are
necessary to ensure that a motor will rotate in a prescribed direction when energized.
There are three other important uses for this unique testing device: it can determine the polarity of power and
instrument transformers; it can identify phase and polarity of winding sections of multiple-winding (delta- and starconnected) motors; and it can be used as a continuity tester in checking electrical circuits.
A four-position switch selects the test to be made — system phase sequence, motor rotation and transformer polarity. The selector switch connects a D-size dry cell into the circuit when the rotation of a motor or the polarity of a transformer is being checked. In the OFF position, both the meter and the battery are disconnected from all circuits.
Fuses are inserted in the motor A and C test leads as protection in the event the user accidentally touches these leads to an energized circuit. These standard fuses are easily removed and replaced from their panel-mounted holders.
The three lines leading to the right of the test set are for direct attachment to energized ac power systems up to 600 volts to determine the system phase sequence.