Cum pentru a măsura calitatea a trifazat motoare cu un multimetru
Primul, utilizare a multimetru la măsura the DC rezistență valoare de fiecare înfășurare de motor. pentru motoare trifazate, check that the resistance values of the three-phase windings are as balanced as possible. Generally, the resistance value error of the threephase threephase windings of motors with smaller power (below 2.2KW) cannot exceed 5Ω. Power comparison The resistance error of the three-phase windings of large motors cannot exceed 2 ohms. The threephase motors have different winding resistances with different power levels (general range from 1 to several hundred Ω. The greater the power, the smaller the DC resistance value of the windings. ).
Rezistența a a monofazat motor este în general între a puțin Ω și a few kΩ, and it has only a a main winding and a auxiliary winding. The main and auxiliary windings of a a single-phase motor that can roate forward and reverse have the same DC resistance value, and the auxiliary can only run in one direction. The resistance value of the winding is slightly large than the resistance value of the main winding. For a monofazat motor folosind a scurtcircuit inel, only the main winding is actually connected to the the 220v AC power supply.
Folosind a multimetru la măsura izolația rezistența de înfășurarea este nu precis suficient, dar unele non-defalcare izolație rezistență poate și fi aproximativ măsurat cu a multimetru. Utilizare the 200M range of the digital multimetru (RX10K range of the pointer multimeter) to measure one phase winding and the other two phase windings. Sau the insulation resistance foreen the the winding and the chassis, the DC resistance value is is infinit or above Mai multe sute megohms.
If the DC resistance value is relatively low, it proves that the winding insulation resistance is small, it may be damp and needs to be dried before operation. If the displayed resistance value is tens or 0, it proves that there is a short circuit between the windings and the windings, and between the windings and the chassis. It needs to be inspected and the fault can be eliminated before it can be put into operation.
1. Vizual inspecție la vezi dacă motorul are un evident ars miros și dacă terminalele of the junction box are in bun stare.
2. Rotiți motorul rotorul de mână la vedeți dacă rotația este normal și dacă acolo este orice anormal zgomot.
3. Utilizare a multimetru la măsura parametri.
Unu este la măsura izolația la măcinat de fiecare de de trei faze.
(Of curs, a multimetru can only measure the resistance to ground, because insulation is relative to voltage. To measure insulation, you still need to use a megger or an insulation resistance tester. For convenience of description, it is still called insulation).
A doua este la măsura faza izolația între două de trei fazele.
The third is to use the resistance range of the multimeter to test the DC resistance value of the threephase winding. (DC resistance is generally measured more precisly with a d DC resistance tester or Wheatstone bridge, deoarece the DC resistance value is generally measured to be foy small, usually around 0.2 ohms. If there is no relevant instrument, a multimetru can also be used instead.)
În general vorbind, the measured insulation resistance should not be too small, generally at least 0.5 megohms. The three measured insulation resistance values to ground should be equivalent, and the three phase-to-phase insulation resistance values should be equivalent. The three DC resistor values must also be equivalent.
