Wiring Harness (Short Circuit) - Test
短路是一种可以导致意外电流的电路故障。 通常,短路是指绕过负载电路。 电路内导线间的短路会在导线中产生过高的电流。 正常电路中的电阻值可能会发生变化,但是特定电路与其它无关电路之间的电阻值应始终大于 5000 欧姆。 下述步骤将说明短路测试:
参考关于完整的电气示意图,请参阅所维修机器的电气系统示意图。
测试是否存在短路。
- 确定可疑电路中的接头和导线编号。 利用机器的电气系统示意图确定这些电路。
- 将钥匙起动开关和断路开关转到 OFF 位置。
- 从配线线束上断开部件和 ECM。
- 在 ECM 机器线束接头可疑导线触点上放上一支万用表表笔。
- 使用另一支万用表表笔检查 ECM 接头中的所有其它触点与机架接地之间的电阻。
预期结果:所有电阻测量值都高于 5000 欧姆。
正常 - 所有电阻测量值都高于 5000 欧姆。 线束电路正常。
停止。
不正常 - 电阻小于 5 欧姆。 机器线束中存在短路。 可疑导线与最低电阻测量值的导线之间短路。
修理:修理或更换机器线束。
停止。
Caterpillar Information System:
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Product Link - PL522/523 Electronic Control Module (ECM) - Flash Program
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