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PROMET SEPrecision Ohm Meter

Condition & Analysis of Electrical contacts Breaker Main ContactsPROMET SE



Effects on a connection



Electrical plant and equipment:Cross temperatures must not be exceeded

Resistance increase with operating time

Heating by power loss

Ageing connectionsWhich problem is to be solved?

Switching devices are essential equipment in a substation.

The current must be interrupted save if a failure occurs.

To guarantee the operation the circuit breaker need maintenance.

Reasons: Wear of the moving parts Leak on valves and seals Failures in control circuits Deterioration of contact parts

Switching devices

Reliable operation is endangered

Power supply companies want to avoid interruptions of energy transport

Inspection and maintenance of equipment

Lifetime and Functionality

Contact: 2 surfaces

Contact surface: rough

Micro contacts

Small effective area Greater resistance

P = R I2

Contact resistance

Which affects the temperature of a connection?

OxidationOxide layer reduce current bearing area

Contact wearMechanical effect movement, friction and arc effect

Contact forceForce can decrease: e.g. loose or misaligned contact

increase the contact temperature, leading to its destruction

Further effects for contact resistance

New solution for connections and switching devicesPROMET SEPrecision Ohm MeterStand-alone unit and external control via ACTAS systems

Static- and dynamic resistance measurement

Stand alone device

Up to 200 A

Small lightweight box

Independent from mains voltage

Static resistance measurement

Quality of contactse.g. busbar, earthing switches,


Via ACTAS Digital communication

Up to 200 A

2 breaks per phaseTotal: 3 x 2 chambers

Connection direct at the chamber Short current and voltage cables Less weight

Static and dynamic measurement Synchronization betweenpoles and chambers

External control


SpecificationsPROMET SEHousingHand case(200 x 178 x 100) mmWith strap for attachment to the breakerTransport caseWeight1,5 kg (without accessories)Connection4 mm safety plugs9 mm high current plugsCurrentup to 200 ACurrent/Voltage channels2Terminal voltage~ 2,5 VDCResistanceup to 200mPower supply- Battery back-up (all day measurement)- External power supply (AC-Adapter)