Running Other Tests; Checking The High Voltage Test Cable; Checking The Low Voltage Test Leads - doble M4000 series User Manual

Checking the High Voltage Test Cable

Running Other Tests

Checking the High Voltage Test Cable
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Continuity
DC Insulation
Resistance

Checking the Low Voltage Test Leads

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4-42
Certain additional tests can be run without gaining access to the M4100
interior. Any of the following tests can and should be run based upon an
indicated error message, symptom or diagnostic test result.
Most of the difficulties encountered with the High Voltage Test Cable are of a
mechanical nature, external, and easily identified. The following resistance
measurements are helpful in locating internal defects that cause erratic or
otherwise abnormal test results.
The High Voltage Test Cable must be isolated for the following
measurements. Disconnect it from the M4100 and the specimen.
The end-to-end resistance of each cable conductor (i.e. the center conductor,
guard shield and ground shield), measured with a low-voltage ohmmeter,
should be less than 1 ohm. If any conductor's resistance is greater, replace the
High Voltage Test Cable.
The DC resistance of insulation between cable circuits (i.e. center conductor to
guard shield and guard shield to ground shield), measured with a low-voltage
instrument (500 V or less) at either end of the cable should be 100 megohms or
greater. If any insulation resistance is less, replace the High Voltage Test
Cable.
The Low Voltage Test Leads are both single-conductor shielded cords
terminated by a clip on one end and a locking plug on the other. Note that Pins
1 and 2 of the inboard connector are short-circuited to each other and
connected to the lead shield. Pin 3 is connected to the center conductor of the
lead to which a clip is attached at the outboard end.
The Low Voltage Test Leads both must be isolated from the M4100 for
the following measurements. Both leads should be tested.
72A-1230 Rev. F