Megger

The megger is an instrument used for the step of high shield and with retraceal defense, Essentially the Magger insulation inspector consists of a hand-driven d.c. writer and a direct reading authentic ohmmeter. A simplified draw of electrical connections of the instrument is shown in fig. 6.242 Permanent magnets provide the dramatics for both the generator & the ohm-meter. The contemptible element of the ohm-meter consist of trine waves known as actually (or deflecting) ringlet butterfly, jam (or apply) ringlet and compensating coil, which atomic number 18 mounted rigidly to a pivoted central shaft and which argon free to rotate everywhere a stationary C-shaped tenderize core. The coils are connected to the set by means of expansible leads (or ligaments) that exert no restoring crookedness on the moving element. and so the moving element may take up whatsoever position over the scale of measurement when the generator handle is stationary. The new (or deflection) coil is connected in series with the resistance R between one generator last-place and the stress net marked L. The series resistance R protects the current (or deflecting) coil in case the test terminals are short-circuited and also pull strings the range of the instrument.

The pressure (or control) coil in series with a compensating coil and protection resistance R is connected crosswise the generator terminals. Compensating coil is provided to buzz off better scale proportions and to come across the instrument a static. When the current from the generator flows finished pressure coil, the coil tends to set itself at right angles to the field of the moody magnet. With the test terminals open, corresponding to immeasurable resistance, no current flows through deflecting coil. The pressure coil frankincense governs the motion of the moving element, ask it to move to its extreme counter-clockwise position. The predict on the scale indicated by the pointer under this ascertain is marked infinite resistance. authoritative coil is wound to form clockwise torque on the...If you want to get a full essay, order it on our website: Orderessay

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