| 摘要 |
PROBLEM TO BE SOLVED: To eliminate unequality in the heat of a heat sink and to improve the cooling effect of a power source device by arranging temp. detecting means in at least two optional places in the heat sink and reversely changing-over the blow direction from a fan in the case that a difference between the output values of the both temp. detecting means becomes more than a prescribed value. SOLUTION: Switching elements fitted to the heat sink for cooling are arranged in a bridge state in a current amplifier 33 in the power source device of an MRI device. A cooling fan A and a temp. sensor A are attached on the entrance side of the heat sink, the fan B and the temp. sensor B are on its exit side, temp. A and temp. B detected by the respective temp. sensors are fetched to a judging means 31 and the difference between A and B is obtained. When the difference becomes more than 5 deg.C, for example, unequality is judged and the rotations of the fans A and B are inverted by a control means 32. Thus the temp. difference between the switching elements is reduced and the unequality of temp. in the entrance and the exit of the heat sink is eliminated.
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