Hi L in Baker AWA-IV 2 kV and Baker AWA-IV 4 kV. 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

Special features of the Baker AWA-IV

Hi L in Baker AWA-IV 2 kV and Baker AWA-IV 4 kV

Hi L is a technique that extends the range of the base surge test circuitry in Baker AWA-IV 2 kV and 4 kV models. This circuitry, like all electrical circuits, has design and operational characteristics that can be enhanced or fine tuned to meet specific additional requirements.

Hi L technique is an example of this.

In essence, the useful range of electric coils that the analyzer can test is dictated by the capacitance (C) supplied by the test set, and the inductance (L) of the coil under test. The “Q” factor—or loss of the test object—also has a direct influence.

Per the data specifications, the Baker AWA-IV 2 kV and Baker AWA-IV 4 kV models are supplied with a .1 microfarad energy storage capacitor. To illustrate the phenomena at work, this value (0.1) shall be the basis of the following discussion.

The sample, or data acquisition window, of the Baker AWA-IV 2 kV and Baker AWA-IV 4 kV is dictated by its analog-to-digital converter and the memory size assigned to it. The maximum sample time of both models is approximately 2 milli-seconds. This illustrates the transient nature of the surge pulse; it is applied, measured, analyzed, and displayed in a fraction of a second.

The Baker AWA-IV 2kV analyzer has a 0.1 micro-farad capacitor. The frequency (f) generated—and therefore, the sample width needed—when a 100 micro-henry coil is tested with the standard surge test is calculated using the following formula:

becomes

when solved, reveals a ringing or resonance frequency of approximately 50 kHz. The period of said 50 kHz sinusoid is equivalent to or approximately 0.00002 second. This is well within the sample window width detailed previously.

What happens to these frequencies if the inductance of the tested coil is raised by several orders of magnitude? For example, what if the coil inductance is now 5 henry, or 50,000 times greater?

when solved, reveals a frequency of approximately 225 hZ

The period of this signal is or approximately .0044 seconds.

PUB CM/I4 71-015 EN V13.2 Static Motor Analyzer—Baker AWA-IV User Manual 109