Applications of megohmmeters and general multimeters
Multimeter ohm gear is mainly used to measure ordinary resistance, range from about 1Ω ~ 200MΩ. megohmmeter is mainly to measure 1M ~ hundreds of megohms of insulation resistance. The starting point of the range differs by millions of times. If we are familiar with the weighing tool to compare, it is like a small electronic scale and the other is a weighing car weighbridge.
It doesn't say which part of the pump is being measured. Because the DC resistance of the pump winding is generally in the tens to hundreds of ohms, if you use a shaking table to measure the equivalent of half a catty of cabbage into the weighbridge, the reading is likely to be zero. This will give a person the feeling that the coil is short-circuited. Because not only is not measured with a shaking table, both the use of multimeter RX10K or 200MΩ file will also show zero.
How to use a multimeter to determine the good and bad capacitors
Capacitor types, in these types of capacitors in the capacitor damage rate is relatively low, such as ceramic capacitors, monolithic capacitors, vitreous enamel capacitors, etc.; some damage rate is relatively high, such as electrolytic capacitors, single-phase motor start capacitors, etc.. In a large number of maintenance of common capacitor damage faults are mainly open-circuit faults in capacitors, capacitor breakdown short-circuit faults and capacitor leakage faults, etc., the following I will talk to friends in this regard.
Capacitor failure appearance check
Some capacitor failure we can see from the appearance can be seen, such as electrolytic capacitor failure can sometimes see the top of the bursting mouth will be bulging or rupture; for like single-phase motor start capacitor will sometimes also find capacitance appearance of bulging appearances. If the capacitor appears the above phenomenon shows that the capacitor has been damaged, must be replaced with the same specifications of the same type of capacitor.
