UNI-T UT261A Phase Sequence Indicator, 40–690 V AC, LCD, CAT III 600 V

UNI-T UT261A Phase Sequence Indicator, 40–690 V AC, LCD, CAT III 600 V

The UNI-T UT261A is a three-phase AC phase sequence and phase-loss indicator designed for checking electrical installations, three-phase equipment and motor supply circuits. Its LCD shows the status of the L1, L2 and L3 phases and indicates the phase sequence, allowing the supply wiring to be verified before connecting three-phase equipment. The UT261A is powered directly from the circuit under test and therefore requires no battery.

Key specifications:
40–690 V AC • 15–400 Hz • phase sequence and phase-loss indication • LCD • CAT III 600 V • IP40 • battery-free

Key features and benefits

• Phase sequence detection – allows the phase order of a three-phase supply to be checked before connecting a motor, pump, compressor or other three-phase equipment.
• Phase-loss indication – the LCD indicates the presence of L1, L2 and L3, helping identify a missing or disconnected phase.
• 40–690 V AC operating range – suitable for various three-phase AC systems within the specified voltage range.
• 15–400 Hz frequency range – supports standard 50/60 Hz mains systems as well as other systems within the specified frequency range.
• LCD indication – phase status and phase sequence are presented on the display for convenient interpretation.
• No battery required – the UT261A is powered from the circuit being tested, eliminating battery replacement and maintenance.
• Operating current below 1 mA – places only a small load on the circuit under test.
• CAT III 600 V rating – intended for use in electrical installation locations falling within the specified CAT III measurement category.
• IP40 rating – the enclosure carries the manufacturer's stated IP40 protection rating.
• Durable design – UNI-T specifies that UT261 series instruments can withstand a drop from a height of up to 2 m.

Applications

The UNI-T UT261A is intended for electricians, electrical installers, maintenance personnel and other users who need to verify phase sequence in three-phase electrical systems.

Typical applications include:

• checking phase order in three-phase power systems;
• identifying a missing or disconnected phase;
• checking the supply before connecting three-phase motors;
• inspection of supply circuits for pumps, fans, compressors and other three-phase equipment;
• electrical installation and maintenance work.

Correct phase sequence is particularly important where the operating direction of a three-phase motor depends on the phase order.

Compatibility and limitations

The UT261A is designed for three-phase AC systems within the manufacturer's specified 40–690 V AC and 15–400 Hz operating ranges.

The UT261A and UT261B should not be confused:

• UT261A provides phase sequence and phase-loss indication on an LCD;
• UT261B additionally provides the motor rotation indication function specified by the manufacturer.

Therefore, the UT261A is not intended to determine the mechanical rotation direction of a disconnected motor. It is also not a general-purpose multimeter and is not specified by the manufacturer as an instrument for precision measurement of voltage magnitude or other electrical quantities.

Technical specifications

Parameter	Specification
Model	UNI-T UT261A
Instrument type	Three-phase phase sequence indicator
Phase sequence detection	Yes
Phase-loss detection	Yes
Indication	LCD
AC voltage operating range	40–690 V AC
Frequency range	15–400 Hz
Operating current	<1 mA
Motor rotation indication	No; this function is provided on the UT261B
Power supply	No battery required
Measurement category	CAT III 600 V
Ingress protection	IP40
Certifications	CE, UKCA, ETL
Manufacturer-specified drop resistance	Up to 2 m
Dimensions	123 × 71 × 29 mm
Net weight	160 g
Product colour	Red / grey

Design and operation

The UT261A uses an LCD to display phase sequence and individual phase status. Three test leads are used to connect the instrument to the phases of the three-phase circuit being checked.

The unit draws its operating power from the circuit under test, so no separate battery or periodic battery replacement is required. The compact enclosure measures 123 × 71 × 29 mm and the instrument weighs 160 g.

Important operating and safety notes

• Use the instrument only within the voltage and frequency ranges specified by the manufacturer.
• Observe the CAT III 600 V measurement-category limits.
• Inspect the test leads and insulation before use.
• Testing a three-phase electrical installation may involve hazardous mains voltages; appropriate electrical safety procedures must therefore be followed.
• An IP40 rating does not provide water protection, so the instrument must not be regarded as waterproof.
• The UT261A indicates electrical phase sequence; the actual mechanical rotation direction of a motor also depends on its wiring and construction.

Package contents

• UNI-T UT261A phase sequence indicator;
• 3 test leads with alligator clips;
• carrying case. ```