PROMET SE - Compact, high-precision ohm meter PROMET SE is a compact, battery-operated ohm meter with an adjustable test current of up to 200 A. Two current outputs and two voltage measurement inputs allow the resistance to be determined at two measurement points simultaneously. Flexible handling with battery operation and the high functionality and precision which are characteristic of the popular PROMET product range make this universal measuring device particularly suitable for portable use in switching stations or industrial environments. Four-wire measuring technology enables PROMET SE to meet the most stringent accuracy requirements, making it ideal for the high-precision determination of resistances in the μΩ range.

1. PROMET SE
Precision Ohm Meter

2. Condition & Analysis of
• Electrical contacts
• Breaker Main Contacts
PROMET SE
Content
 Problem
 Effects on a connection
 Solution
PROMET SE

3.  Electrical plant and equipment:
Cross temperatures must not be exceeded
 Resistance increase with operating time
 Heating by power loss
 Ageing connections
Which problem is to be solved?

4.  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

5.  Reliable operation is endangered
 Power supply companies want to avoid interruptions of
energy transport
 Inspection and maintenance of equipment
Lifetime and Functionality

6.  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?

7.  Oxidation
Oxide layer  reduce current bearing area
 Contact wear
Mechanical effect  movement, friction and arc effect
 Contact force
Force can decrease: e.g. loose or misaligned contact
 increase the contact temperature, leading to its destruction
Further effects for contact resistance

8. New solution for connections and switching devices
PROMET SE
Precision Ohm Meter
Stand-alone unit and external control via ACTAS systems
Static- and dynamic resistance measurement

9.  Stand alone device
 Up to 200 A
 Small lightweight box
 Independent from mains voltage
 Static resistance measurement
 Quality of contacts
e.g. busbar, earthing switches, …
Stand-alone

10.  Via ACTAS
• Digital communication
 Up to 200 A
 2 breaks per phase
Total: 3 x 2 chambers
 Connection direct at the chamber
• Short current and voltage cables
• Less weight
 Static and dynamic measurement
• Synchronization between
poles and chambers
External control
PROMET SE
PROMET SE

11. Specifications
PROMET SE
Housing Hand case
(200 x 178 x 100) mm
With strap for attachment to the breaker
Transport case
Weight 1,5 kg (without accessories)
Connection 4 mm safety plugs
9 mm high current plugs
Current up to 200 A
Current/Voltage
channels
2
Terminal
voltage
~ 2,5 VDC
Resistance up to 200mΩ
Power supply - Battery back-up (all day measurement)
- External power supply (AC-Adapter)