| 摘要 |
An electrical system wherein an intrinsic safety barrier between electrical field apparatus and a DC supply source therefor includes voltage threshold devices connected from both lines at the field end to ground to protect against excess voltages, and current limiters in both lines between the source and field ends for preventing current above a predetermined value from flowing in the lines regardless of voltage or loading values. The current limiter in one line includes an electric valve in series in the line, which valve is turned OFF in response to loss of the aforementioned ground connection. Diodes in both lines oppose wrong polarity voltages that might be applied thereto. |
