Current limiter or circuit breaker? How to protect 24 V load circuits
In the control cabinet, one power supply usually feeds many loads. If a short circuit occurs in one circuit, only this circuit should switch off. All others should keep running. This is exactly where circuit breakers on switching power supplies reach their limits.
Why the circuit breaker often does not trip
A miniature circuit breaker trips quickly in a short circuit when a multiple of its rated current flows. For characteristic B this is 3 to 5 times, for characteristic C 5 to 10 times. A C6 breaker therefore needs 30 to 60 A.
A switching power supply, however, limits its output current itself. A 10 A power supply delivers only slightly more than its rated current for a short time in a short circuit. The breaker does not trip quickly. Instead, the voltage drops for all loads and the whole machine stops.
The solution: electronic current limiter
An electronic current limiter sits between power supply and load circuits. It monitors each channel individually and switches off only the affected channel in case of overload or short circuit. It does not need a high short circuit current to do so. The remaining channels stay supplied.
- Selective disconnection per channel
- Adjustable tripping current per channel, for example 0.5 A to 10 A on the ESB10.4
- Reliable function even with small power supplies
- Less downtime, faster troubleshooting
Which current limiter fits?
- ESB10.2: 2 channels of 10 A, 10 to 31 V DC, trip thresholds 2, 4, 6 and 10 A
- ESB10.4: 4 channels of 10 A for 24 V DC
- ESB10.8: 8 channels of 10 A, 7 to 30 V DC
- ESB10.4-48 and ESB10.8-48: 4 or 8 channels for 48 V DC
- POWER-TEC10.4: 4 channels of 10 A, 22 to 28 V DC
When does the circuit breaker still make sense?
On the AC side upstream of the power supply and wherever high short circuit currents are available, the circuit breaker remains the right choice. For 24 V load circuits behind a switching power supply, the electronic current limiter is the more reliable solution.
Questions about selection? Write to dc-vertrieb@woehrle-svs.de or call +49 7157 7374 506.