论文标题
实现Bullard的Disc Dynamo
Realization of Bullard's disc dynamo
论文作者
论文摘要
我们报告了三个成功运行的Bullard型同型圆盘发电机的实验结果。该设置由半径为30 cm的铜盘组成，厚度为3 cm，该铜盘由相同尺寸的平坦的多臂螺旋线圈共放置，并通过滑动液体金属触点在中心和周长的圆周上进行电气连接。使用固定在线圈顶面上的霍尔探针测量磁场。我们还测量了整个线圈上的径向电压下降。当圆盘旋转速率达到$ω\约7 $ Hz时，磁场在线圈的中央部分陡峭地增加了$ b_ {0} \约40 $ mt。该场比背景磁场强两个以上的数量级以上。在前两次运行中，电磁扭矩在发电机状态下制动圆盘超过了驱动盘的电动机的故障扭矩。结果，电动机停滞不前，发电机被中断。当驾驶频率设置得更高并更快时，在第三次运行中不会发生停滞。我们还提出了一个扩展的圆盘发电机模型，该模型可定性地再现实验结果。
We report experimental results from three successful runs of a Bullard-type homopolar disc dynamo. The set-up consisted of a copper disc with a radius of 30 cm and thickness of 3 cm which was placed co-axially beneath a flat, multi-arm spiral coil of the same size and connected to it electrically at the centre and along the circumference by sliding liquid-metal contacts. The magnetic field was measured using Hall probes which were fixed on the top face of the coil. We measured also the radial voltage drop across the coil. When the disc rotation rate reached $Ω\approx 7$ Hz, the magnetic field increased steeply approaching $B_{0}\approx 40$ mT in the central part of the coil. This field was more than two orders of magnitude stronger than the background magnetic field. In the first two runs, the electromagnetic torque braking the disc in the dynamo regime exceeded the breakdown torque of the electric motor driving the disc. As a result, the motor stalled and the dynamo was interrupted. Stalling did not occur in the third run when the driving frequency was set higher and increased faster. We also propose an extended disc dynamo model which qualitatively reproduces the experimental results.
