| 摘要 |
A solid state overload protective apparatus for an AC load(2) supplied power from an AC source (L1 - L3) comprising means (4) to sense actual current supplied to said load (2) from said AC source (L1-L3)and means (36) to convert said actual current to a first voltage (V3) proportional to said actual current. Means (32) is provided to generate a second voltage from said first voltage (V3), said second voltage proportional to an approximate value equal to the rms current of said load (2) and means (44) is provided for integrating said second voltage to provide a trip signal (V10) representative of a predetermined full load carrying capacity of said AC load (2). Comparison means (46) is provided for comparing said trip signal (V10) with a predetermined trip reference voltage level (12), said comparator means (46) producing a drive output signal when said trip signal (V10) is a lessor magnitude that said trip reference voltage level (12), and said comparator means (46) producing a turn-off drive output signal when said trip signal (V10) is a greater magnitude than said trip reference voltage level (12) indicative of an overload condition; and means (22) for removing said AC source from said load (2) responsive to said drive output signal when said overload condition exists. <IMAGE> |
