What are the requirements for measuring the insulation resistance of hydraulic motors? Dalan Motor tells you the specific requirements are as follows: 1. When measuring the insulation resistance of the winding of the hydraulic motor, if the head and tail of the three-phase winding can be separately wired, the windings should be separately measured on the casing (to the ground) and the phases and phases. The insulation resistance between. 2. If it has been integrated (triangle or star), only the insulation resistance of the entire winding to the casing can be measured. 3. It should be selected according to the rated working voltage of the tested winding on the oil pump motor, see the following table: Winding rated voltage (V) Megohmmeter specification (V) ≤36 250 >36~500 500 >500~3000 1000 > 3000 2500 4. When measuring temperature measuring components or other special devices embedded in the windings, a megohmmeter of not more than 250V is generally used. 5. The method of using the megohmmeter is as follows: 1 If the insulation resistance of the winding to the casing is measured, the end marked with L should be connected to the winding of the motor, and the end marked with E should be connected with the casing of the motor. 2 When measuring, the shaking speed should be as uniform as possible, preferably 120 rpm ("two turns for one second"). After the needle is stabilized to a position, the reading is determined to determine the measurement result. Under normal circumstances, it should be shaken for about 1 minute. 3 In order to prevent the influence of insulation damage caused by insulation damage on the two lead contact parts of the instrument, separate two leads should be used. If necessary, shake the generator to check the insulation of the lead and other parts of the instrument before the formal measurement. When normal, the meter indication should be infinite (∞). 6. Qualification standard of insulation resistance of motor winding 1 When the motor winding is at working temperature, the insulation resistance value should reach the following formula: R≥UN÷{1000+PN÷100}(megohm) where: R-motor insulation resistance (Mega); UN-motor rated voltage (V); PN-motor rated power (KW) 2 According to the above formula resistance value is the resistance value of the hot state 75 ° C, which is the national standard requirement. Reference formula for cold resistance value: RMC≥U÷1000×(75-t)÷5 where: RMC-cold resistance evaluation value (megaohm); t-measurement winding temperature (°C); u-winding Rated voltage (V) 3 motors are typically measured in the cold state to determine if the motor winding insulation is normal. How to give the standard at this time, GB14711-2006 stipulates that the low-voltage motor (1100V and below) should be no less than 5MΩ. There is no specific regulation for high-voltage motors, which generally needs to be determined by both parties. 7. Insulation absorption ratio of motor 1 For large-capacity motor windings, the moisture content should be checked by measuring the absorption ratio. When the moisture is severe, even if the insulation resistance is qualified, it can not be put into use. The correct method is to dry the motor windings and measure the absorption ratio. If it meets the requirements, put it into normal use. The absorption ratio of the two windings is the ratio of the two insulation resistance values ​​from the start of the shaking to the 15th and 60s. B represents the absorption ratio, and Rm15 and Rm60 represent the two insulation resistance values ​​at the 15s and 60s, respectively, and are expressed by the formula: B = Rm60/Rm15. 3 The acceptance criterion of the absorption ratio is B ≥ 1.3, if B
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