四、试验台研制中几个 主要问题的探讨 1.动力的选择 试验台采用的动力,常见的有两种,一种是用拖拉机原配发动机,这样与实际情况一致,匹配良好,但调节范围窄。如当试验台要求转速和负载作频繁迅速的变化,发动机上则必须增设闭环控制系统,费用较大,且在技术上很难完全满足要求。另一种是用调速电机,调速范围广,工作时噪声低又无有害气体排出,易于实现自动控制,所以一般 Fourth, the test bed in the development of several major issues 1. Selection of power test bed used in the power, there are two common, one is the original engine with a tractor, so consistent with the actual situation, a good match, but the adjustment range is narrow . Such as when the test bed requires frequent and rapid changes in speed and load, you must add a closed-loop control system on the engine, the cost is larger, and technically difficult to fully meet the requirements. The other is the use of speed motor, speed range, low noise and no harmful gas discharge, easy to achieve automatic control, so the general