The Pico MT03A Milliohm and Motor Tester is designed for technicians, engineers, automotive specialists, industrial maintenance teams and research laboratories that need accurate low-resistance measurements.
It combines milliohm resistance testing, single-phase and three-phase motor winding testing, earth-bond measurement and temperature-compensated analysis in one USB-connected test system. Pico specifies a current resistance measurement range that autoranges up to 5 Ω, with a resolution of 10 µΩ and typical accuracy of ±(0.5% + 100 µΩ).
Precision Low-Resistance Measurement
The MT03A is designed for applications where conventional multimeters may not provide sufficient resolution for very low resistance values.
Key measurement specifications include:
- Resistance range: Autoranging up to 5 Ω
- Resistance resolution: 10 µΩ
- Typical resistance accuracy: ±(0.5% + 100 µΩ)
- Input protection: ±30 V
- Temperature compensation: Supported using the supplied temperature sensor
These capabilities make the MT03A suitable for measuring small resistance changes in windings, cables, earth bonds, busbars and electrical connections.
Three-Phase Motor Winding Resistance Testing
The MT03A can measure the resistance of all windings on a three-phase motor in under one minute.
It uses three Kelvin-connected measurement paths, allowing the resistance of the motor phases to be checked efficiently without repeatedly moving a conventional pair of test leads.
This is useful for identifying potential problems such as:
- Winding imbalance
- Loose electrical connections
- High-resistance joints
- Damaged windings
- Poor terminal connections
- Changes in motor winding resistance
- Electrical faults developing between phases
The software can display and compare winding resistance values to help engineers evaluate phase balance.
Single-Phase Motor Testing
The MT03A is not limited to three-phase systems.
It can also be used for low-resistance measurements on compatible single-phase motors and electrical components where detailed winding or connection resistance needs to be evaluated.
Typical uses include:
- Motor repair
- Preventive maintenance
- Manufacturing quality control
- Electrical troubleshooting
- Component verification
- Workshop testing
Temperature-Compensated Resistance Measurement
Electrical resistance changes with temperature, particularly in copper windings.
The MT03A includes a dedicated temperature sensor input and can automatically compensate measured resistance values according to temperature. This helps engineers compare the measured winding resistance against manufacturer specifications referenced to a standard temperature.
The current sensor specification provides:
- Temperature measurement range: −40 °C to +125 °C
- Temperature resolution: 0.2 °C
- Typical temperature accuracy: ±0.5 °C
Pico identifies the supported temperature sensor as TA527.
Temperature compensation can help prevent a healthy motor from appearing outside specification simply because the winding temperature differs from the manufacturer's reference condition.
Kelvin 4-Wire Resistance Measurement
The MT03A uses Kelvin measurement techniques to reduce the influence of test-lead and contact resistance.
Kelvin clips separate the current-injection and voltage-sensing paths, allowing the tester to measure the voltage drop close to the component under test rather than including the resistance of the test leads in the result.
This technique is especially useful for:
- Milliohm measurements
- Motor windings
- Busbars
- Earth straps
- Cable connections
- Welded joints
- High-current connections
Pico includes Kelvin clips with the MT03A kit.
Earth-Bond Testing
The MT03A also supports earth-bond resistance testing.
Pico states that the tester supports earth-bond testing in accordance with UN ECE R100 requirements and provides a minimum test current of 200 mA for relevant low-resistance measurements.
Typical earth-bond applications include:
- Electric vehicles
- High-voltage vehicle systems
- Chassis bonding
- Safety earth connections
- Ground straps
- ECU earth connections
- Battery and starter cables
- Welded conductive joints
- Electrical enclosures
For UN ECE R100 applications, Pico highlights measurement of resistance between exposed conductive parts and the electrical chassis.
Electric Vehicle Testing
The MT03A is particularly useful in electric and hybrid vehicle diagnostic environments.
Applications can include:
- Traction motor winding resistance
- Electric motor phase comparison
- Earth-bond testing
- HV component grounding
- Battery-system connections
- Busbar connections
- High-voltage cable connections
- Chassis bonding
- Electrical safety verification
Pico developed the MT03A for use across automotive, industrial and other electrical maintenance applications.
Transformer and Generator Testing
Pico also identifies the MT03A for applications including:
- Transmission transformers
- Distribution transformers
- Servo motors
- Generators
Low-resistance measurement can be useful for checking windings, connections and conductive paths in these systems.
USB PC Connectivity
The MT03A connects directly to a Windows computer through USB.
The USB connection provides:
- Data communication
- Power to the tester
- Software control
- Measurement display
- Data analysis
- Reporting
No separate external power supply is required during normal USB operation.
Dedicated MT03A Software
Pico provides dedicated Windows software for controlling the tester and reviewing measurement results.
The software supports:
- Resistance measurement
- Three-phase motor tests
- Temperature-compensated resistance
- Phase comparison
- Test-result display
- Measurement analysis
- Reporting
The current PC requirement is:
- Windows 10 or Windows 11
- 64-bit application
Typical Applications
The Pico MT03A is suitable for:
- Single-phase motor testing
- Three-phase motor testing
- Motor winding resistance testing
- Milliohm resistance measurements
- Earth-bond testing
- Electric vehicle diagnostics
- Hybrid vehicle testing
- Transformer testing
- Generator testing
- Servo motor testing
- Busbar resistance testing
- Ground strap testing
- Electrical cable testing
- Weld contact verification
- Industrial maintenance
- Rail applications
- HVAC systems
- Elevators and escalators
- Water-treatment equipment
- Mining and drilling
- Wind turbines and renewable energy
- Scientific research
- Manufacturing quality control
