Baker D30R, User'S Manual & Operating Instructions

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D30R Users Manual
88
Do Not Touch Test Leads while test is in Progress!
71-023 Rev C 5/8/2007
4. Perform the test as described in Three Phase Motor Surge Test and
Set-Up.
For each test, check the display for a wave pattern. Recall a SUMMARY from
the digital tester’s memory for wave patterns for the motor to compare. If three
good wave comparisons are seen, there is every indication to believe the motor
is good. If anything other than good patterns are visible, there is a possible fault.
Determination of a Fault
If any wave pattern becomes erratic and/or flickers during testing, intermittent
shorting or arcing is probably occurring in the windings under the voltage stress.
Arcing is often accompanied by audible sounds. It may be desirable to store the
wave pattern produced by this arcing for reference if the operator can release the
Test (this freezes the wave pattern) at the moment when the wave pattern
appears the most affected (reduced amplitude and increased frequency or shift to
the left).
Separation in two of three wave pattern comparisons indicates incorrect turns
count. The fault will be in the phase connected to the test lead in common
between the two comparisons which show the separation for wye-connected
windings.
In the Repair Shop: separation of compared wave patterns on Stators indicates a
hard fault, such as a solid turn-to-turn or group-to-group short, an incorrect turns
count, or misconnections.
In the Field: In assembled motors, separation of the wave patterns is often the
effect of rotor coupling, also known as rotor loading (see Rotor Loading
(Coupling) when Testing Assembled Motors).
Two or More Single Coils
Surge testing can be used to test two or more identical single coils separately
and then compare their wave patterns against each other.
1. Connect test lead #1 to one side of coil #1 and connect the ground test
lead to the other side.