The shaking table, also known as megohmmeter, is mainly used to measure the insulation resistance of electrical equipment. It is composed of the AC generator voltage doubling rectifier circuit and the component at the top of the table. When the shaking table shakes, it generates a DC working voltage. When it is insulated with a certain voltage, the insulation material will flow with extremely weak current. The current consists of three parts, namely, capacitive current, leakage current and absorption current. The ratio of DC working voltage to leakage current generated by shaking table is insulation resistance. Using shaking table to check whether the selection of insulation material is qualified is called insulation resistance test, which can find out whether the insulation material is damp, damaged and aging in time, so as to find out the defects of enterprise equipment management.
the rated 25Voltage of megohmmeter is 25,5,1,25 v, and the measuring range is 5,1,2 m Ω.
(1) It usually has a voltage of 5,1,25 megohms. Which predetermined megohmmeter should be selected for the voltage level of the device?
(2) When measuring the insulation resistance of technical equipment, the working power supply must be cut off first. For the equipment (such as capacitors, transformers, motors and cable lines) that have great influence on improving capacitance, it is necessary to develop and analyze the discharge first.
(3) the megohmmeter should be placed in a horizontal position, and the megohmmeter should be shaken first to see if the pointer is ∞, then the two terminals of "L" and "E" are short-circuited, and the megohmmeter should be shaken slowly to see if the pointer refers to "zero". Pan-European semiconductor short-circuit checklist should not be used.
(4) Multi-strand flexible wires are used for megohmmeter reference wires, and they should have a good insulation.
(5) In a thunderstorm or when the double-loop overhead lines and buses cannot be completely cut off. When the induced voltage of the tested circuit exceeds 12 volts, overhead lines and electrical equipment connected with overhead lines shall not be measured.
(6) Measuring capacitors, cables, transformers and large-capacity motors have a certain charging time. The greater the capacitance change, the longer the charging learning time should be. Generally speaking, the megger reads the theme one minute after the rotation.
(7) When measuring the resistance of insulating materials by shaking, the megger should be kept at the basic rated working speed, which is generally 12 rpm. When the capacitance of the measured object is large, the rotating speed can be appropriately increased (for example, 13rpm) to avoid the pointer swinging.
(8) The measured surface should be wiped clean without dirt, so as not to affect the accuracy of measuring the drain.
(9) Do not touch the measuring system part and the terminal of the megohmmeter by hand before the megohmmeter stops rotating and the equipment does not discharge, so as to avoid electric shock.
difference between shaking table and megohmmeter
shake the table to avoid accidents and measure the insulation resistance of various electrical equipment for megohmmeter.
Megger is commonly known as shaking table. Most megger measurements are powered by manual hand-cranked generators, so it is also called shaking table. Its scale is megahertz (mω), and electricians usually use it as measuring instruments. Megohmmeter can be mainly used to check the insulation resistance of electrical engineering equipment, household appliances or electrical control lines to ground and interphase, so as to ensure the normal development of our technical equipment, electrical appliances and line management and avoid accidents such as electric shock casualties and equipment damage in enterprises.
Responder: UHV power.