Electronic Circuit Breakers (ECBs)
WAGO's Space-Saving Electronic Circuit Breakers
WAGO's EPSITRON® ECBs have a lot to offer in the way of performance and features. They not only provide reliable protection against overloading and short circuiting, they also enable activation of high-capacity loads of 50,000 microfarad and higher – without having to increase the nominal current setting. One, two-, four- and eight-channel models with 0.5–12 A current ratings offer you the flexibility you need for setting the nominal current for your individual applications. With a maximum width of 45 mm, WAGO's ECBs feature high channel density, providing space-saving installation in the control cabinet. Some devices are also available with active current limitation, preventing the power supply unit from overloading during a short circuit.
Advantages of WAGO's Electronic Circuit Breakers:
Why secondary-side fuse protection?
On the secondary side, switched-mode power supplies provide DC voltage to control circuit loads (e.g., controllers, operating panels, displays and auxiliary relays). These control circuits also call for wiring protection and if the load has no protective unit of its own, device protection as well. Furthermore, Machinery Directive EN 60204 requires the detection of hazardous ground faults in control circuits and switching off within five seconds.
The overcurrent protection in primary switched-mode power supplies reacts very quickly to overcurrents on the output side. Selective protection of individual current paths in the secondary circuit via fuses or conventional circuit breakers is often ineffective, if the power supply cannot deliver a brief overcurrent.
What types of fuse protection are there?
10-fold overcurrent (related to the fuse nominal current):
Tripping within range 30 ms (best case) or 200 ms (worst case)
Only 2-fold overcurrent: Tripping within range 2 s (best case) or > 100 s (worst case)
|Thermal and Magnetic||Picture example:|
3 … 5-fold overcurrent for B-characteristic and AC operation, additional safety factor:
1.2 or 1.5
Thus, in the worst case a tripping current of 7.5 times the nominal current is necessary.
|Electronic||Electronic circuit breakers (ECBs) ensure reliable protection, even at low overcurrents and long cable lengths.|
How does an ECB function?
The ECB verifies that the output current is greater than the nominal current. As soon as the output current exceeds the nominal current, the output is electronically switched off by a semiconductor switch. The trip time depends on the magnitude of the overcurrent. The measurement of the output current, processing and calculation of the tripping time, as well as actuation of the semiconductor switch are performed by a microprocessor that monitors one or more output channels. The corresponding tripping times can be taken from the graph on the right.
- Switch off secondary-side overcurrents and short circuits – even with long cable runs and small conductor cross-sections – precisely, fast and repeatedly
- Selectivity, especially with ECBs having active current limitation
- Remote operation via digital input and output
- Readout functions (communication) through serial data transfer via digital input and output
- Beneficial installation size and width, for example, 8 output channels in just 42 mm (save more than 70% of installation space compared to miniature circuit breakers)
- Nominal current assignable for each channel
- Satisfy EN 60204-1 requirements for dependably switching off ground faults after five seconds (see right)