Ideal Phase / Motor / Transformer Testing

Ideal Phase / Motor / Transformer Testing

Ideal Phase and Rotation Meters

Phase Sequence and Motor Rotation Testers have two primary functions. Both are necessary to ensure that a motor will rotate in a prescribed direction when energized.

Determine the rotation direction of motors: clockwise or counterclockwise, before connecting line voltage. Running motors backwards/wrong direction may damage expensive machinery. In these cases, motors are tested on a bench or temporary power is run to uncoupled motors for a rotation test. This can be costly, time-consuming, and hazardous, especially with high voltage motors. Using a motor and phase rotation tester, an electrician can make the final motor connections on the first attempt.

Determine phase rotation or sequence of energized power circuits: The load side (i.e. unpowered motor) and also the supply side should be checked. The phases of the line voltage must also be properly identified so that they can be connected to the motor for the desired rotation. This is true in a new or replacement motor situation, but also when working on switchgear, such as transformers, disconnects, and breakers. Utility crews or plant personnel working on switchgear must correctly connect or the result might be many backward rotating motors at different locations when power is re-applied. This can be very dangerous, plus possibly damage equipment.

Additional uses for Phase Sequence and Motor Rotation Testers

• Identifying polarity and phase of motor windings where the terminal markings have been destroyed or where connection diagrams are lost
• Determine polarity of instrument and power transformers
• Continuity tester in checking electrical circuits

How to select a phase and motor rotation meter?

• Make sure to have the right CAT safety rating for the voltages of live circuits being tested. Potential transformers (step-down transformer) are required for measurements on systems above the common CAT IV 600 V // CAT III 1000 V limit of many phase and motor rotation testers. Click here to learn more about CAT safety ratings.
• Dedicated Phasing Testers are available for utility work in the kV range. Applications include checking high voltage fuses, testing for correct phase connections, and testing for absence of high voltage on de-energized lines.
• Each phase meter varies slightly in the layout of buttons/switches, LED’s, and operation. Some have a buzzer in addition to LED. Our site has instruction manuals under each instrument so you can get a detailed look at a meter before purchasing (ask if not posted).

• Certain Phase Detectors feature non-contact clips, reducing risk of electric shock and short circuit hazards. The clips do not have any exposed metal to contact the conductor. Clip right over 10-40 mm insulated wires. Certain Ideal Phase Testers have no exposed metal parts. These are essentailly the same as non-contact clips. This combined with Ideal's shock resistant meter housings means your risk of shock or shorting is greatly reduced.