(1) Monitor the load current of concrete mixer motor. When the motor breaks down, the stator current will increase sharply and the motor will overheat. The mixer with larger power shall be equipped with an ammeter to monitor the load current of the motor. The load current of the motor shall not exceed the rated current specified on the rating plate.

(2)监视电源电压。频率的变化和电压的不平衡度、电源电压和频率的过高或过低、三相电压的不平衡造成的电流不平衡都可能引起电动机过热或其他不正常现象。

(2) Monitor the supply voltage. The change of frequency and the unbalance of voltage, the too high or too low power supply voltage and frequency, the unbalance of current caused by the unbalance of three-phase voltage may cause motor overheating or other abnormal phenomena.

(3)对绕线型混凝土搅拌机转子电动机。应检夜电刷与滑环间的接触、电刷房损以反火花情况，如火花严重必须及时清理滑环表面，并校正电刷弹簧压力。

(3) The rotor motor of wound type concrete mixer. Check the contact between the brush and the slip ring, the damage of the brush room and the anti spark condition. If the spark is serious, clean the slip ring surface in time and correct the brush spring pressure.

(4)经常检查轴承润滑情况，定期更换润滑油。更换润滑油时，应将轴承及轴承盖用煤油清洗·并后用汽油洗干净。滚动轴承润沿脂不宜超过轴承室容积的70％。

(4) Check the lubrication of the bearing regularly and change the lubricating oil regularly. When changing the lubricating oil, the bearing and bearing cover should be cleaned with kerosene and then with gasoline. The lubricating grease of rolling bearing should not exceed 70% of the volume of bearing chamber.

(5)注意保持电动机内部的清洁．不允许有水而、油污以及杂物等落人混凝土搅拌机电动机内部。搅拌机电动机的进风口和出风口必须保持畅通。

(5) Pay attention to keep the inside of the motor clean. No water, oil and debris are allowed to fall into the motor of the concrete mixer. The air inlet and outlet of mixer motor must be kept smooth.

(6)注意电动机的气味、振动和噪声。运行中如闻到焦味或发现不正常的振动或碰擦声、特大的嗡嗡声或其他杂声时，应立即停电检查。

(6) Pay attention to the smell, vibration and noise of the motor. In case of burning smell, abnormal vibration or rubbing sound, extra loud buzzing or other noises during operation, the power shall be cut off immediately for inspection.