Electronic Circuit Breakers for Industry 4.0 enabled systems

FASTER PROTECTION

Electronic circuit breakers

For Industry 4.0-enabled systems: BLOCK promises an individually configurable circuit breaker system with a new fast tripping characteristic that meets all requirements.

The clear benefit of electronic device protection

Familiar protection concepts based on fuses and traditional standard circuit breakers often do not work as desired in combination with switched-mode power supplies. The reason why: A short-term overcurrent is required for the magnetic quick tripping of standard circuit breakers. Yet the physics even imposes limits when a switched-mode power supply is used with high power reserves: long wires and small cross-sections prevent the necessary current flow for tripping a miniature circuit breaker due to high line impedance.

Electronic solutions are therefore the only sensible and cost-effective method for supplying a large number of sensors and actuators in the field with cable lengths of more than 100 m on the 24V DC side. Electronic circuit breakers are specially adjusted to the behaviour of switched-mode power supplies and to the supplying DC loads. They divide the load current into several circuits for reliable fuse protection of connected loads and their supply lines, including with long line lengths and small cross-sections.

Challenges with the protection of 24V DC circuits

Using different tripping characteristics to suit the requirements of the relevant load is common practice when designing conventional fuse protection concepts based on standard circuit breakers or fuses. Various requirements are imposed on the tripping characteristics of the protective devices in machines and systems: loads with high starting and inrush currents such as drives and contactors, for instance, require different tripping characteristics to sensors and control units that react sensitively to system voltage drops.

Little attention is paid to the characteristics of electronic solutions, unlike with traditional fuse protection for DC circuits. Manufacturers generally offer a universal characteristic that is ideally intended to function for all applications. In reality, the options offered by different manufacturers differ considerably.

When electronic device protection is used, a further switch-off mechanism must also be taken into account which is not known to the conventional solution, and which is not apparent from the tripping characteristic: i.e. the undervoltage switch-off.  Whereas conventional standard circuit breakers only react to thermal tripping due to overload and electromagnetic rapid tripping in the event of a short circuit, electronic solutions also trigger a shutdown in the event of unwanted system voltage drops. These can occur if the power supply unit cuts the power more quickly than the protective device is able to trip in the event of a short circuit.

The interaction between the power supply, load requirements and the tripping characteristics of the protective device must therefore also be considered for each application with electronic fuse protection concepts.

EasyB provides the right tripping characteristic for every application

The electronic circuit breakers from BLOCK are designed for a variety of requirements in machines and devices. Both the multi-channel circuit breakers from the Power Compact and Power Mini series, as well as the EasyB single-channel system, are available with two different tripping characteristics in each case, in order to provide the user with the optimum solution for the relevant application. Loads that do not tolerate short-term system voltage drops can receive optimum protection from an electronic circuit breaker with active current limitation. By comparison, a characteristic that deliberately permits high peak currents for a short period but which nevertheless switches off reliably in the event of a short circuit, even if the selected tripping current is only exceeded marginally, provides the optimum characteristic for protecting drives and contactors.

BLOCK is expanding the EasyB series to include a new fast tripping characteristic in the aim of responding even more effectively to the various requirements of electronic protection concepts in future. This guarantees safe and secure tripping within 2 ms in the event of a short circuit. Not only that, but all characteristics in the EasyB system can be combined with each other within the network in order to adapt the tripping characteristics to the requirements of the loads specific to the relevant channels.      

One system – three tripping characteristics                                                   

Slow (standard):

Ideal for protecting loads with high inrush or start-up currents. Contactors, drives and valves can be reliably operated and fused in combination with a high-performance power supply unit from BLOCK’s Power Compact series. Capacitive loads > 40mF can be connected and engaged safely and securely.

Fast:

The new characteristic in the EasyB series reacts significantly faster than the standard characteristic – particularly at rated currents <6A – and trips reliably within 2 ms in the event of a short circuit. Suitable for universal use and also ideal for loads that react sensitively to brief system voltage drops, such as control systems. The switch-on capacity within the 10 mF - 50 mF range is adequate for most applications.

Current-limiting:

A current-limiting characteristic is recommended for fuse protection of particularly sensitive loads or above-average load capacities. Although it is less suitable for loads with recurring high inrush or starting currents during operation, this characteristic also offers the possibility of charging highly capacitive loads > 70 mF with constant current when the supply voltage is switched on, without the need for a power supply unit that is oversized for the starting torque.

Worldwide applicability guaranteed as a result of compliance with comprehensive standards and certifications

(Standards and certifications can be used worldwide)

The EasyB series is consistently UL-certified in accordance with UL 508 and UL 2367. In addition, both the channels with current-limiting characteristics and the new versions with fast characteristics are NEC Class 2-approved for the current range 1A - 4A.

Whether for mechanical and plant engineering, wind power or transportation, EasyB series circuit breakers are optimally protected from the strain of shock and vibration and are accordingly DNV GL-certified.

The internal fuses are adapted individually in each case to the rated current from 1A to 10A comply with IEC 60127-4/2 as well as UL 248-14. The system also, of course, meets line protection requirements in accordance with EN 60204-1.

EasyB – more than just device protection

The modular EasyB circuit breaker system provides added value to the user that goes beyond the core functionality of line protection. Scalable functionality and equipment from the cost-effective version with basic functionality and tripping characteristics tailored to the relevant application, through to the intelligent power distribution and fuse protection system with fieldbus connection to the higher-level control level via different bus couplers. Messages regarding operating and error states for each channel are therefore available easily and quickly. Any output channels desired by the user can also be configured, actively switched on or off and reset. There is also an option for setting the tripping current via the communication bus. The IO-Link interface, in particular, can also provide the benefit of a cost-effective fieldbus-independent communication interface in this application. EasyB, therefore, has all the necessary attributes to set up Industry 4.0-enabled systems in condition monitoring and predictive maintenance.

EasyB will be available soon at RS Components

For more information on EasyB please follow the link below.

BLOCK Electronic Circuit Breakers

Author: Jens Marten, Head of Electronic Development, Electronics Product Manager, BLOCK
March 2020