Permanent magnet motor safety box with insulation direct current resistance detection function

The invention relates to a permanent magnet motor safety box with an insulation direct current resistance detection function. The safety box is connected with a power output interface of a frequency converter through an alternating current power line. The number of the alternating current power lines is two, and the two alternating current power lines are provided with power switches. A main loop control module, a pump working condition detector, a feed detection circuit, an insulation detection circuit and an interphase resistance measuring circuit are arranged in the box body of the safety box; the main loop control module comprises a power supply indication loop, a contactor indication loop, a power-off delay loop and a starting circuit which are connected in parallel; two nodes of the parallel circuit are respectively connected with an alternating current power line; a main contactor is arranged in the starting circuit, and three wiring copper bars are arranged at the wiring position above the main contac