The results of experimental study of two-stage explosive magnetic generator with magnetic flux trapping (EMG MFT) and opening switch in the primary circuit are presented. It was shown that this type of generator demands less than 3 μs to achieve the maximum of current derivative (30 - 100 kA/μs) and maximum of the output voltage. The generators with such parameters are necessary for a number of loads, for example, for the plasma accelerator with growing inductance. At the same time the problem of emerging surge in the secondary circuit of the generator was solved through the introduction of a separate single-turn closing switch with high breakdown voltage. The comparison of the performance of two types of EMG MFT is described. The first type generator was with opening switch in the primary circuit, the second one was without breaking of the primary circuit. They had approximately the same initial input parameters (inductances of the primary and the secondary circuits and the coupling coefficients) and the same inductance of model load - 1.16 μH.