In the analysis of the dynamic characteristics of cryostating systems of SC installations carried out earlier in [2], the authors omitted an account of a number of factors which have a noticeable effect on the thermal stability of current-carrying elements to lengthy pulsed heat liberation, chiefly the change of magnetic induction over the radius of the magnet windings; and that means also along the cryostating channels. Characteristic of the coils of the toroidal field is a substantial nonuniformity of distribution of the thermal load and of the flow rate of helium in different channels, and this nonuniformity is greater in cooling of coils by helium at subcritical pressure. In tests of assembly blocks T-15 on the complex SIMS it was also established that the temperature of the helium at the inlet to the winding is higher than the initial assumed value of 4.5 K, and this also has to be taken into account. In [2] the effect of the current-carrying element itself on the thermal stability was not taken into account, and the possibility of stabilizing the windings by superheated helium at subcritical pressure was not examined. Let us consider the results of the calculations of the dynamic characteristics of cryostating systems which make it possible to evaluate their advantages and shortcomings in different variants of cooling the windings. The calculations were carried out for an Oshaped coil of the toroidal field shown in [i]. The main characteristics of the c0il are: the superconductor is made on the basis of a niobium-tin compound; the outer and inner diameter of the coil is 3.1 and 2.1 m, respectively; the length of the spiral cryostating channel is 340 m; its inner diameter is 2.8 m~n. The condition of cooling the coil is: the temperature of the cryogen at the inlet to the coil is 4.7 K when it is cooled by supercritical helium and helium at subcritical pressure with subcooling at the inlet; in cooling by helium at subcritical pressure the mass vapor content of cryogen at the inlet to the winding is 0.i; the pressure at the outlet from the winding is 0.I and 0.5 MPa, respectively, for subcritical and supercritical helium; the helium enters the channel from the side of the small radius of the winding. The magnetic induction of the coil decreases from its center to the periphery. Magnetic induction Bma x is equal to 8.2 and 6.4 T, respectively, with forced and nominal operating regime of the blocks T-15 [3]. The steady-state thermal load of the coil is 90 W which corresponds to the data obtained on the complex SIMS. The fraction of heat penetrating through the housing of the coil to the winding was taken to be equal to 0.7. For individual disks of the coil the degree of nonuniformity in regard to thermal load is equal to 1.8 and 3, in regard to the flow rate of helium it is 1.06 and 1.4, respectively, for supercritical helium and for helium at subcritical pressure. The degree of nonuniformity in regard to thermal load and flow rate of helium shows how many times greater the thermal load and smaller the flow rate of helium is on the outermost disk which is in direct contact with the housing of the coil in comparison with the mean values (for all the disks of the coil) of these parameters.