| 摘要 |
An eddy-current (vehicle) retarder, has an electronic control unit 3 actuated by means of a multiposition handle 4 to connect a D.C. voltage source 2 of amplitude V to the inductor windings 1 of the retarder. The windings 1 are arranged so that their supply at a voltage of 0.65 V volts causes the retarder to develop its maximum permissible braking torque for permanent operation, and the electronic unit 3 transmits a voltage increasing from 0 to 0.65 V volts when the handle 4 is moved from its first position O to its last but one position C, this voltage becoming equal to V only when the control handle is moved into its end position D against a spring 6 to give braking over torque, the spring 6 acting as a safety means. The period of over- excitation corresponding to this last position may be limited by other safety means, e.g. a timing device (optionally adjustable), or means sensitive to temperature of an element heated by the retarder or to any parameter tied to such a temperature. <IMAGE>
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