Breaker & Contact Resistance Test

Advanced diagnostic instruments for circuit breaker timing, contact resistance, coil analysis, motion measurement, and dynamic resistance testing.

Circuit breakers are the last line of defense in a power system. A breaker that fails to operate correctly — or fails to operate at all — can turn a manageable fault into a major outage or equipment loss. ProgUSA supplies DV Power circuit breaker and contact resistance test equipment to utilities, electrical service providers, and industrial facilities across the United States, backed by application support, training, calibration, and repair.

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What breaker and contact resistance test equipment covers

Contact resistance measurement (micro-ohmmeter testing)
Dynamic resistance measurement (DRM) for contact condition assessment
Circuit breaker timing and travel measurement
Motion and velocity measurement
Coil resistance and coil current measurement (IEC 62271-100)
Minimum trip voltage testing (IEC 56, ANSI C37.09)
Undervoltage release testing (IEC 60694)
Mechanism charging time measurement (IEC 62271-100)
Pre-insertion resistor contact timing and resistance
Auxiliary contacts timing measurement
First trip testing
Disconnector analysis

Common applications

Where this equipment is used

Utility substation maintenance and commissioning
Transmission and distribution circuit breaker programs
Medium and high voltage breaker acceptance testing
Condition-based maintenance and fingerprinting programs
NETA and electrical service contractor field testing
Manufacturing and factory testing
Industrial switchgear maintenance

DV Power Logo

Circuit Breaker Analyzers & Timers

Field-portable analyzers for circuit breaker contact timing, motion parameters, voltage recording, resistance measurement, and analog signal capture. Supports standalone and PC-controlled operation via DV-Win software. Enables fingerprinting and result comparison across test intervals to detect performance changes over time. Key capabilities:

Main, auxiliary, and pre-insertion contact timing
Motion and velocity measurement
Voltage recording
Analog signal measurement
DV-Win test plans and graph overlay for trending

CAT-P CAT-H

Handheld Micro-Ohmeters - RMO-H Series

The RMO-H is the only handheld micro-ohmmeter on the market with regulated, user-selectable test current up to 300 A DC — in a package weighing under 1 kg / 2.1 lbs. Six models cover cable lengths from 1.3 m to over 5 m, with two battery configurations for short and long lead applications. All models support Both Sides Grounded (BSG) testing for maximum safety in energized substation environments.

Up to 300 A regulated DC — ripple-free, no rest time between tests
Battery powered — full day of testing on a single charge
Stores up to 1,000 measurements; Bluetooth sync to free DV Win software
BSG-capable for substation safety compliance
Six models: RMO-H1 / H2 / H3 (short leads) and RMO-H21 / H22 / H23 (long leads)
Compliant with IEEE C37.09 and IEC 62271-100

RMO-H Talk to ProgUSA About the Right Model

Portable Micro-Ohmmeters — RMO-G Series

Field-portable instruments for contact resistance measurement of medium and high voltage circuit breakers. Accurate low-resistance measurement confirms contact condition and identifies degradation before it leads to failure or overheating.

Contact resistance measurement per IEEE C37.09 and IEC 62271-100
High test current output for accurate micro-ohm readings
Results stored and compared against manufacturer limits

RMO-200G

Advanced Time/Motion/Contact DRM Analyzers

The CAT66 analyzer by DV Power extends the capabilities of the CAT64, adding an internal 300A micro-ohmmeter for static contact resistance measurement and dynamic graphing of arcing contact resistance. This feature allows for diagnostic analysis of arcing contacts without the need to open the circuit breaker.

Advanced Capabilities: Includes static and dynamic contact resistance measurements.
Diagnostic Tool: Enables analysis of arcing contacts.

CAT-66

Most Advanced CB Analyzer: CAT500

The CAT500 is the latest and most advanced circuit breaker analyzer in the DV Power lineup. It features BSG (Both Sides Grounded) technology, supports up to 12 main contacts, and includes a 10” graphical touch screen for simplified PC software downloads, minimizing IT department issues.

Advanced Features: BSG technology and support for up to 12 main contacts.
User-friendly: 10” graphical touch screen.

CAT-500

Entry-Level Circuit Breaker Analyzers

DV Power introduces the CAT100 and CAT250 circuit breaker timers/analyzers for your budget cycle. The CAT100 features a 7” screen and battery power, while the CAT250 offers a 10” graphic touch display with advanced features. Both models allow for extensive analysis and viewing directly on the device displays or via a PC.

CAT100: Basic model with a 7” screen and battery power.
CAT250: Feature-packed model with a 10” graphic touch display.

CAT100 CAT250

Substation Ground Grid Integrity Tester: GGT300N

DV Power’s GGT300N is designed for testing the integrity of substation ground grids. This model performs multiple point-to-point tests with 300A DC applied for 90 seconds, allowing for easy detection of faulty underground joints and cables. It is highly portable, weighing under 20lbs, and optional 200ft test cables are available.

High Current Testing: 300A DC applied for comprehensive testing.
Portable: Weighs under 20lbs with optional 200ft test cables.

GGT300N

CB Portable Power Supply: SAT40a

The SAT40a combines the functionalities of the POB-40D with the accurate measurement of coil resistance, making it an ideal tool for optimal coil testing. CB coil failures are a common weakness in MV and HV circuit breakers.

Combined Functionality: Includes coil resistance measurement.
Reliability Testing: Addresses a common weakness in circuit breakers.

SAT40a

CB Coil Tester: POB40D

DV Power’s POB40D CB Coil Tester is perfect for verifying adequate power supply to CB coils and spring charger motors, especially during commissioning when station DC is unavailable. It ensures coils operate at the lower end of their supply voltage rating.