1. Hand touch method: a method of estimating the temperature of the motor according to the strength of the hand touch by touching the specified part of the motor by hand. See the table. Relationship between surface temperature and feel of motor casing Case surface temperature °C Feel Description 30 Slightly cold Lower than body temperature, feeling a little cold 40 Slightly warm Feel the degree of warmth 45 mild Feel warm when touched by hand 50 Slightly hot Touching the hand for a long time, the palm turns red 55 heat Only use hand to touch 5~6s 60 Hotter Only use hand to touch 3~4s 65 very hot Only touch the hand for 2~3s. After the hand leaves, the palm still feels hot. 70 very hot Only one 3s can be touched with one finger 75 Extremely hot Touch with a finger, can endure 1 ~ 2s 80 Extremely hot, suspect that the motor has burned out I can't touch it with a finger, vinyl crimping 85～90 Extremely hot, suspect that the motor has burned out If you touch it with your finger, it’s like burning it. 2. Thermometer method: The temperature rise of the motor is directly measured by a thermometer. Al2O3 Ceramic Ring, High Purity Ceramic Ring, 99% Aluminum Ceramic Ring Yixing Guangming Special Ceramics Co.,Ltd , https://www.yxgmtc.com