KoCoS Blog

Filtered by category Circuit breaker testing Reset filter

Compact motor and coil testing system for switchgear testing

KoCoS Messtechnik AG now offers the compact, portable EPOS MC4 test system for the supply, testing and analysis of motors and trip coils of switching devices.
In addition to its use as a powerful AC/DC source, EPOS MC4 records the operating currents of spring tensioning and pump motors as well as release coils and displays the motor and coil currents as numerical results on a 5" touchscreen.

The voltage source is based on state-of-the-art power electronics and is insensitive to interference in the power supply due to the synthetic generation of the output variables. Test sequences can therefore always be carried out under the same conditions, which enables a direct comparison of the results.

The EPOS MC4 can be operated and controlled via the integrated operating unit with high-resolution, resistive 5" touchscreen, rotary selector switch and function keys or in combination with the ACTAS test systems. EPOS MC4 can be conveniently integrated into switchgear tests via the ACTAS test software. A remote control unit is also available for controlling motor and coil outputs.

EPOS MC4 provides additional functions for analyzing switchgear:

  1. Analysis of motor running and coil tripping
  2. Determination of the coil resistance
  3. Determination of the minimum tripping voltage
  4. Testing undervoltage releases

The evaluation of the results is simple and conclusions about the condition of coils, motors and mechanics can be drawn immediately. The integrated measuring functions therefore guarantee meaningful analyses for maximum operating times and minimum maintenance effort.

EPOS MC4 enables the direct connection of a PC/notebook. The measurement results stored in the device can be read out and managed using easy-to-use software.

The test system is housed in a handy, extremely robust and hard-wearing hard case. Waterproof and dustproof to IP67 when closed, the case absorbs even hard knocks without sustaining damage. The robust test system is just as suitable for demanding outdoor use as it is for use in production or in the laboratory.

For many years, KoCoS has been recognized as the world's leading manufacturer of switchgear test systems. With the new ACTAS P260+ and ACTAS P360+ switchgear test systems, KoCoS now offers two portable devices which once again overtop the previous series in terms of performance.

  1. Larger range of functions thanks to new hardware and software features
  2. Increased flexibility in switchgear testing
  3. Improved ergonomics, functionality and performance
  4. Operation via integrated operating unit with 7" touch screen and/or the specially developed test software
  5. Easy operation with optimal display of all information
  6. Built in an extremely robust and compact case housing

ACTAS P360+ has been extended by two controllable outputs in the form of relays, which can be easily integrated into the test sequence. This also works retroactively with existing test templates from the pre-production series. ACTAS P260+ also received two additional control outputs, one also in the form of a relay, the other as an IGBT control output. For example, the reserve output coil of a switchgear can be connected directly without reconnection, which enables the connection of one input and two output coils simultaneously. The systems offer another major advantage with the display of measurement data oversampled at 200 kHz at 50 kHz.

There is also news in the testing software. ACTAS EXPERT is now generally included in the scope of delivery and offers some additional functions. Among other things, it is possible to export measurement data in various formats, to overlay measurement data using the measurement history and compare them directly, or to insert envelopes as a reference. For the display and analysis of the data, you can also create your own display graphics, which are also used in the corresponding test reports.

Do you have any questions, additions to the topic or would you like to convince yourself of the performance of the systems during a product demonstration online or in person at your premises? Then feel free to contact us via the comment function here in the blog or by e-mail to cstuden(at)kocos.com.

When we talk about "P L C" at KoCoS, we don't mean the programmable logic controller but our various ACTAS test systems. But why does KoCoS offer three different ACTAS product lines?

Quite simply! KoCoS serves the entire mechanical switch testing market with its three different ACTAS product lines. Starting with fully automatic routine testing at the switchgear manufacturer, through the service technician to the test laboratory. The requirements of the various applications can only be optimally met with different devices.


Use of the ACTAS test systems


ACTAS Portable           Service Technician (manual testing)


ACTAS Laboratory       Test laboratories, production, development (semi-automatic testing)


ACTAS Cabinet            Test laboratories, production, development (fully automatic testing)

However, the situation is quite different when it comes to testing software, where an end-to-end solution is important:

With ACTAS 2.60, all tests can be performed with all ACTAS test systems. This is essential in order to be able to reuse tests and test results throughout the entire life of the switchgear. It is then possible to test a switch with ACTAS from the start of its development through to its use in the field, e.g. under using the same templates. For example, the test parameters and limit values developed in the laboratory with ACTAS L can be used directly during routine testing as part of the quality assurance process with ACTAS C. With ACTAS P, the service technician is then also able to access the original parameters during maintenance.

Almost all major switchgear manufacturers, test laboratories and also service technicians appreciate this and take advantage of the great ACTAS benefit of being able to use measuring instruments flexibly for the various applications and to fall back on existing data.

Any questions or additions to the topic? Then please use the comment function here on the blog or send an email to cstuden(at)kocos.com.

A look inside the switchgear chamber "Dynamic Timing" and "Dynamic Resistance

In contrast to evaluation via a simple binary signal, as is the case with high-frequency measurement methods, the use of switchgear test systems ACTAS in combination with resistance measuring devices PROMET allows a well-founded diagnosis of breaker units throughout the entire switching process. The result of the measurement is displayed in the form of a curve in which all events of a switching operation can be seen in detail. An exact assessment of the start of movement and end position of the contacts is thus made possible, even time differences between the movements of the main and resistor contacts become visible.

Evaluation of the breaker unit by means of contact resistance analysis

Regular measurements of the static and dynamic contact resistance allow precise statements to be made about the condition of the entire contact system. Necessary maintenance work can thus be detected at an early stage and downtimes prevented. With the PROMET SE resistance measuring device, contact resistance measurements can be carried out on up to 12 or more interrupters and directly integrated into the overall test sequence. The test current can be set up to a maximum of 200 A. Even very small resistances in the single-digit microohm range can be measured with extremely high accuracy. The measured values are included in the evaluation of the test and output in the test report.

A high contact resistance within a switching device leads to a high power loss, combined with thermal stress and possible destruction of the switching device. Faults, such as high contact resistance due to defective connections, can be detected by measuring the static contact resistance. With the dynamic contact resistance measurement, the resistance curve is determined during a switching operation that can be defined as desired. The measurement allows, for example, conclusions to be drawn about the length and condition of arcing contacts in high-voltage switches.


Any questions or additions to the topic? Then please use the comment function here on the blog or send an email to cstuden(at)kocos.com .

Is it possible to perform a switching time measurement on a medium voltage system encapsulated in SF6 gas?

KoCoS offers a measuring method using the ACTAS switchgear test systems and external sensors which enables this type of system to be tested at a reasonable cost. As the system does not need to be isolated, the measurement procedure is even less time consuming than testing a non-gas-insulated medium-voltage switchgear using the conventional measurement procedures.

The VDS (Voltage Detection System) installed in the systems is used to measure the switching times. These are capacitive measuring points for voltage indicators or integrated capacitive voltage indicators according to VDE 0682-415 or IEC 61243-5. If no voltage transformers are installed, these measuring points are the only and safe way to establish a connection to the main contacts of the circuit breakers.

The capacitive measuring points can be connected directly to the analog measuring inputs of the ACTAS test system provided for this purpose without interposing additional measuring components. The capacitive measuring points are used to measure the three-phase sine wave of the voltages. If the circuit breaker is switched via the control room, the voltage drop is displayed on the ACTAS test system. However, in order to be able to determine a switching time, current clamps are used and attached to the open and close coils. External trigger signals that can be set in the test system can be used to initiate the recording of the measured values and the corresponding evaluation. External triggers can be set in ACTAS to any signals, regardless of whether they are individual binary or analog signals or signal groups.

The evaluation of the switching time in ACTAS is fully automatic; there is no need to set a cursor to manually evaluate the switching times and enter values manually.