Technical library

This application note describes tap changer testing in general and details on how to use the capabilities inMTO210, 300 and 330 for tap changer measurements. It is not replacing the MTO user manuals where generaloperation of the instrument and connection schemes for various transformers is described.

The BITE3 battery impedance tester comes standard with a built in spectrum analyzer. The spectrum analyzer gives the user the ability to examine the frequency content of the ripple current on their batteries. By examining the ripple frequency the health of the charger can be verified.

Performing ohmic testing on parallel strings:  Parallel strings present a challenge when performing ohmic testing. This is because a parallel battery string has multiple paths for the test current to flow. In a series string the injected test current only has one path, through the battery under test. Since the all the test current goes through the battery under test a proper repeatable measurement is made.

What is NERC? How does it affect my battery maintenance practices? Founded in 1968, NERC was first known as the National Electric Reliability Council. NERC was created   in   response   to   the   1965   blackout,   where   30 million people lost power.

Before starting testing of an electrical installation, Megger Limited recommends that the risk assessment should consider the use of fusted test leads.

OTS vessel preparation and elimination of the effects of moisture and contamination

Safety Warnings for OTD

Test the breaker at first operation after a longer period of static position.Trip the circuit breaker from stationcontrol (Local or remote system). During operation coil currents are recorded by current clamps connected toTM1700 control part or TM1800 analog module. 3 phase timing are  recorded by current clamps in secondarycircuit station of current transformers (in the bay). The “timing” current clamps are connected to the analogchannels.

The CAT (Category) rating of a test instrument defines where in the electrical supply chain the instrument can besafely used. This is usually printed on the instrument across the test connections and appears as CAT II, CAT III orCAT IV. CAT I is generally no longer used, as it has no practical application.

Megger has been manufacturing low resistance ohm meters for many years. In fact the first Low resistanceohmmeter was launched in 1908. The first low resistance ohm meter, launched under the DUCTER trade markwas developed by Evershed and Vignoles (one of the companies that evolved into Megger) and used a cross-coils meter movement. Today, Megger has a comprehensive range of Digital Low Resistance Ohmmeters,under the DLRO trade mark, providing accurate and reliable measurements with test currents ranging from afew μA to 600 A suitable for many applications.