If you are reading this blog, it might be because it is time to break out a Micro-Ohmmeter to ensure the reliability of electrical connections throughout your electrical power system. The Vanguard Auto-Ohm is the ideal tool to use when evaluating the integrity of electrical bonds to power system equipment, as well as the contact resistance within the electrical equipment itself.
A 10 ampere Digital Low Resistance Ohmmeter is sufficient for many low resistance measurement applications. However, industry standards and guidelines will recommend, if not require a minimum of a 100 amps DC source when evaluating connections relating to medium and high voltage power system apparatus. Very small changes in contact resistance can have significant impacts on these apparatus in terms of how they perform in service. The use of higher current helps in the precision of the measurement and is therefore preferred when evaluating connections in higher voltage applications.
TheAEMC 6250 Micro-Ohmmeteris uniquely designed to conduct tests on both resistive and inductive material, with operator selection directly from the front panel. Three test modes are available: resistive (instantaneous test), inductive (continuous test), and auto (repetitive test). Up to 1500 measurements can be stored and printed directly to a printer or from a PC.
Circuit breaker or relay contacts, bus bars and switchgears constantly carry high currents. If the junctions deteriorate, the current carrying efficiency may be reduced and cause several problems like welding of contacts, localized Ohmic heating and eventual component failure.
Protec carries a full line of AEMC products that includes clamp-on meters, DC Current probes, transformer turn ratio meters, megohmmeters, micro ohmmeters, ground resistance test sets and other electrical test instruments.
Industries that consume vast amounts of electrical power must include low resistance ohmmeter measurements in their maintenance operations. Not only does abnormally high resistance cause unwanted heating, possibly leading to danger, but it also causes energy losses which increase operating costs.