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Safety First with the Doble M4000 and M4100

Doble M4000 M4100 Power Factor Insulation AnalyzerThe Doble M4000 M4100 Power Factor Insulation Analyzer supplies test voltage and test current to insulation apparatus.

The Doble M4000 M4100 Power Factor Insulation Analyzer also contains measuring circuits to determine the condition of the insulation under test, as well as direct control safety circuits to ensure electrical safety of personnel and test instruments.

The M4100 has a time base generator that may be synchronized either with the power system supplying power to the test instrument, or with an internal crystal oscillator. This choice allows the test operator to select one of two modes of test operation, Line Sync Reversal or Line Frequency Modulation.

When Line Sync Reversal Mode is selected, the time base is synchronized to the power source and the test will use the standard Doble polarity reversal technique to reverse the effects of electrostatic interference.

Selecting the Line Frequency Modulation Mode of operation will synchronize the time base generator to the crystal oscillator. Two tests will be run for each programmed test sequence. The first test is run at a frequency of 57 Hz and the second test is run at 63 Hz. The measured test results of each test are combined and averaged to give a 60 Hz equivalent test result. When operating in the 50 Hz frequency, the same technique will apply. The first test will run at 47 Hz, and the second test will run at 53 Hz. This mode of test eliminates electrostatic interference from measurement, by avoiding measurement at power line frequency. It is also possible to select ± 10% of power line frequency as well.

Safety circuits have been designed into the M4100 to ensure safety of personnel. High voltage will not be supplied by the instrument if either of the following circuits and conditions are not satisfied:

• The ground safety circuit verifies that the #6 bare copper safety ground, which is attached from the instrument to the apparatus earth ground, is at the same potential as the power supply ground.

• Two safety switches must be attached to the M4100 front panel and in the closed or depressed position prior to testing. One switch is held by the M4000 operator and the second switch is held by a safety supervisor. The M4100 can be configured to require both switches to be opened between test sequences for the M4000 Insulation Analyzer to operate. Release of one or both switches will terminate the test sequence and high voltage potential.

A safety strobe light can be used in conjunction with the instrument and is plugged into the front panel of the M4100. Whenever high voltage potential is applied from the M4100, the safety strobe light will be energized and flashing.

Safety strobe connection will be required in order to operate the M4000 Insulation Analyzer, unless the default system configuration has been modified to allow for the absence of a safety strobe. In this case, the strobe connector can be removed from the M4100 front panel.

Related electrical test equipment available for rent from Protec:

Omicron CPC 100 Multi-Functional Primary Test System

Doble M4110 Leakage Reactance Module

Megger DELTA4000 Series 12 kV Insulation Diagnostic System

With multiple locations to better serve your needs, Protec offers electrical testing equipment rental options that work for you.

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