l. For generators powered by internal combustion engines, the internal combustion engine part should be operated in strict accordance with the operation safety of the internal combustion engine. 2. For generators newly installed, overhauled or out of service for more than 10 days, the insulation resistance and absorption ratio of the stator and excitation circuit should be measured before use. The insulation resistance of the stator should not be less than 30% of the last measured value.