Test configuration. SKF Baker AWA-IV 4 kV, Baker AWA-IV 12 kV, Baker AWA-IV 12 HO, Baker AWA-IV Series, Baker AWA-IV 2 kV

Baker AWA-IV software overview

Test configuration

Three setup windows are used to configure tests: Temperature/Resistance, DC Tests, and

Surge Tests. Each window is described below.

Settings and parameters specified in the setup windows define the Test ID. If you want to update parameters for all motors using the selected Test ID, check the Edit Test ID box before editing test parameters. You can then save your changes when finished.

Temperature/Resistance test setup window

When one of the temperature or resistance test configuration buttons is clicked, the

Temperature/Resistance Test setup window appears. The resistance and temperature test parameters are combined into one window as shown below.

The temperature entry and resistance test can be turned on or off using the enable radio buttons on the left side of the window.

Figure 57. Temperature/Resistance test window.

The temperature entry is used to acquire the motor’s temperature (as close as possible to the winding). Some motors may even have temperature detectors installed, but other methods such as scanning guns can be used to acquire the motor (winding) temperature. The temperature collected via the external devices is entered manually in this setup window.

Temperature can be entered in degrees Celsius or Fahrenheit.

The temperature acquired at test time is used during testing to temperature correct coil resistance values per IEEE 118 and insulation resistance values per IEEE 43/95.

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Baker AWA-IV software overview

Resistance measurements can be influenced by humidity. To enable setting the relative humidity, check the Relative Humidity box then enter the humidity present. Click on Accept to commit the settings. .

The resistance test has several options. The test can be performed on a two-lead device such as a single coil or a three-lead device such as a three-phase motor. The motor may have wye or delta winding configurations. The wye or delta configuration is entered in the nameplate window and is defined here based on that entry.

Figure 58. Resistance enabled.

Resistance values can be automatically acquired by the analyzer, or by some other means and manually entered into the software. The method for entering or obtaining resistance data is described later.

By checking the Delta R (%) box, the resistance values will have their percent spread calculated at the end of the test. If the percent spread is outside the number entered in the corresponding field, the motor will fail the resistance test.

The acquired resistance values may be temperature corrected by checking the Correct to box and defining the related parameter in the adjacent field.

The temperature the resistance value is corrected to is set to 25o C by default, but it can be changed to another value. IEEE 118 recommends 25o C. The constant used to convert resistances at one temperature to another is known as the IEEE 118 constant and is 234.5 for copper or 224.1 for aluminum.

A motor that does not have a resistance reading within a target resistance range can also fail.

Correct this issue by checking the Target Corrected Resistance box and entering the expected corrected resistance values and tolerances.

NOTE

Only temperature corrected values will be used in determining if values are within tolerance.

At the end of the test, the analyzer compares corrected resistance readings to the target corrected resistance to determine if the motor passes.

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Baker AWA-IV software overview

The lower portion of the Temperature/ Resistance Test window contains buttons used in manual and semi-automatic testing. It also include three columns that display test results for all testing options. The Delta R average result is also displayed here.

Three columns report measured line-to-line resistance, temperature corrected resistance, and calculated coil resistance values.

As mentioned previously, there are two ways to obtain resistance data. In automatic mode, the analyzer will measure the resistance when you click on the Automatic radio button. The second way is to manually measure the leads using a precision resistance bridge then directly entering the values into the corresponding Measured L-L fields.

NOTE

A precision resistance bridge is a typical example of a device that is sensitive enough to collect accurate data to use in resistance imbalance calculation. It is most important to ensure that the instrument used can give you accuracy that is consistent with the measurement being made and the device being measured.

Figure 59. Test Results section of the Temperature/Resistance Test setup window.

Another key difference between the automatic and manual modes is that the automatic mode will make a resistance measurement per your specifications between a lead with the other two leads held at ground. A balance test can be done, or the low-voltage leads can be used for a more precise test.

A resistance value that is manually entered will be different: a measurement made with a bridge will be between two leads with a third lead allowed to float. Due to this difference, the winding configuration becomes even more important. The Baker AWA-IV software assumes that manually entered data will be made with a two-lead precision bridge and that the third lead is allowed to float. Clearly, a wye motor’s lead-to-lead measurement will be different from a delta lead-to-lead measurement.

Regardless of how the resistance measurements are acquired, after they are obtained the software will calculate the temperature corrected resistances and display them. Additionally, if possible, the analyzer will calculate the individual coil resistances. If not, the software will display a message indicating that a solution to the coil resistance could not be found.

While the Temperature / Resistance window is open, there are several ways to start a resistance test measurement:

1) Click the Test All Leads button. The analyzer then measures each lead’s resistance sequentially (semi-automatic testing).

2) Click one of the lead buttons on the Baker AWA-IV front panel. The analyzer then measures the resistance of the clicked lead only and displays the results (manual testing).

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