中文
含义
F7E1 表示洗衣机主控板无法从转速传感器（测速发电机/霍尔传感器）获取有效的电机转速反馈信号。肯摩尔洗衣机通过安装在驱动电机后端的转速传感器实时监测电机运转速度，主控板根据该信号调节洗涤和脱水的转速及加速度。当电机启动后控制板在连续数秒内未检测到转速脉冲信号，或检测到的转速与指令转速偏差超过允许范围，系统即判定转速传感器故障并触发 F7E1，电机停止运转。
常见原因
- 转速传感器（霍尔元件或测速线圈）本体损坏，内部磁铁退磁或线圈断路，无法产生转速脉冲信号输出。
- 电机与转速传感器之间的磁性信号盘（tone wheel / magnet ring）脱落、碎裂或被油污覆盖，传感器无法感应到磁场变化。
- 转速传感器与控制板之间的连接线束因电机振动导致内部铜丝疲劳断裂，或插接器端子氧化接触不良。
- 电机电刷磨损严重（有刷电机机型），碳刷粉末积聚在换向器和传感器周围造成信号干扰。
- 主控板上的转速信号调理电路（如比较器或 ADC 输入通道）损坏，即使传感器正常也读不到数据。
- 传动皮带过松打滑或断裂，电机虽然旋转但滚筒/波轮未随之转动，控制板收到的实际转速与预期严重不匹配。
自助排查
- 拔掉电源，等待 10 分钟让主控板电容充分放电后重新插电，运行一次快速洗涤程序（不放衣物），观察 F7E1 是否复现。
- 打开洗衣机后盖板，目视检查电机后端的转速传感器线束插头是否松脱，将插头用力按紧确保完全卡入。
- 沿着转速传感器线束检查是否有被机壳边缘磨损或折断的痕迹，重点关注线束与金属框架接触区域的绝缘层状况。
- 取下驱动皮带，手动旋转电机轴，感受是否有卡滞、异响或转动不均匀的情况，必要时清理电机轴上的缠绕物。
- 检查传动皮带的张力和磨损状态：如皮带表面有裂纹、硬化或明显拉长松弛，需更换同规格皮带。
- 如以上步骤无效，用万用表交流电压档测量转速传感器输出端的脉冲电压（需维修手册参考值），无输出则需更换传感器或整个电机总成。
- 传感器线束和皮带均正常时，故障指向主控板转速检测电路故障，联系肯摩尔售后更换主控板。
English
Meaning
F7E1 indicates that the main control board is unable to obtain a valid motor speed feedback signal from the tachometer (speed sensor / Hall sensor). Kenmore washers monitor motor rotation speed in real time via a speed sensor mounted on the rear of the drive motor. The control board uses this signal to regulate wash and spin speeds and acceleration. When the motor starts but the control board detects no speed pulse signal for several consecutive seconds, or the detected speed deviates beyond the allowable range from the commanded speed, the system flags a speed sensor fault, triggers F7E1, and stops the motor.
Common Causes
- The speed sensor itself (Hall element or tachometer coil) is damaged — internal magnet demagnetization or coil open circuit, unable to generate speed pulse output.
- The magnetic tone wheel or magnet ring between the motor and the speed sensor has fallen off, cracked, or is covered in grease and oil, preventing the sensor from detecting magnetic field changes.
- The wiring harness between the speed sensor and control board has internal copper wire fatigue breaks caused by motor vibration, or the connector terminals are oxidized and making poor contact.
- Motor brushes are severely worn (on brush-type motor models), with carbon dust accumulating around the commutator and sensor causing signal interference.
- The speed signal conditioning circuit on the main control board (such as comparator or ADC input channel) is damaged, failing to read data even when the sensor is functional.
- The drive belt is excessively loose, slipping, or broken — the motor spins but the drum or pulsator does not follow, causing a severe mismatch between actual and expected speed.
Self-Check Steps
- Unplug the washer, wait 10 minutes for the control board capacitors to fully discharge, then plug back in. Run a quick wash cycle (empty) and observe whether F7E1 reappears.
- Remove the rear access panel, visually inspect the speed sensor wiring connector at the motor rear for looseness, and firmly push the connector until it fully seats.
- Trace the speed sensor wiring harness for signs of abrasion or breaks where it contacts the cabinet edges, focusing on insulation condition at points where the harness touches the metal frame.
- Remove the drive belt, manually rotate the motor shaft, and feel for binding, unusual noise, or uneven rotation. Clear any debris wrapped around the motor shaft if needed.
- Inspect the drive belt for tension and wear: if the belt surface is cracked, hardened, or visibly stretched and loose, replace it with a same-specification belt.
- If the above steps are ineffective, measure the pulse voltage at the speed sensor output using a multimeter in AC voltage mode (refer to the service manual for reference values). No output indicates the sensor or entire motor assembly needs replacement.
- When both the sensor harness and belt check fine, the fault points to a control board speed detection circuit failure. Contact Kenmore after-sales service for control board replacement.