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Baker WinAST

Baker WinAST

Automated Stator Testing System

Baker WinAST with test fixture

Manufacturers of stators, coils, alternators, rotors and other kinds of motor windings need advanced, dependable and proven test systems. If the ability to conduct common in-process electrical tests in one custom built automated test instrument is required, look to SKF’s Baker WinAST automated stator test system.

Hipot, surge and temperature-compensated resistance test capabilities are standard. A rotation-direction test is optional for testing stators and field coils. Because each tester is a semi-custom instrument assembled to customer specifications, its capabilities are not limited to those described here; additional features are available. For more information, contact SKF Condition Monitoring Center – Fort Collins at 970-282-1200, or send an inquiry to [email protected].

Baker WinAST operation

Baker WinAST systems not only test manufactured products, they also test manufacturing processes. Trends within the manufacturing process can be monitored allowing the anticipation of problems. The Baker WinAST system is set apart from other winding test systems because of its highly-sensitive computer-controlled testing, analysis and report generation software. The Baker WinAST computer makes testing virtually automatic.

Ease of use: To test a winding, a master data file is created. In a manually-loaded system, the operator merely starts each test from the test fixture. When each test is complete, a pass/fail indication is clearly displayed on the screen and on the operator’s control console. The Baker WinAST can be integrated into fully automated lines with automatic fixtures and a PLC (or host computer) communications interface.

No master winding needed: Connection of a master winding is unnecessary during routine production testing. An operator does not need to set the test voltages or pass/fail limits during model changeover, saving time. Test parameters are programmed into a master data file. Programming winding models takes just a few minutes. The Baker WinAST’s programme has a simple, pull-down menu-driven interface. The user is prompted for all necessary information. Once the master has been defined, it is permanently stored. Testing is then automatically sequenced according to the master file.

AC and DC tests: For AC hipot (high potential) testing, the Baker WinAST uses arc detection to sense breakdowns to ground or between windings that may go undetected using average current measurement techniques. The instrument also has capacitive compensation capability. This measures the resistive portion of the leakage current, rather than the total current. DC hipot testing checks the integrity of the insulation system with high DC voltage. Leakage current is then measured in micro-amps instead of milli-amps.

Surge test: The high voltage surge or impulse test checks for insulation problems between turns, coils and phases of the winding. Surge tests can detect other faults that change the inductance of a winding, such as improperly annealed lamination steel and reversed coils. The surge test also has the ability to detect corona caused by weak insulation.

Resistance test: The resistance test checks for wrong turns count, poor connections, mislabelled leads and incorrect wire size. With the use of Kelvin connections, low resistance winding tests are accurate and repeatable. Resistance measurements are temperature corrected to the equivalent resistance value of 25 °C (77 °F).

Rotation direction: The optional rotation direction test is for stator testing. Both induction and Hall-effect type sensors are available. This test is also capable of detecting bad connections in some cases.

Reports and statistics

Reports can be displayed on the monitor, printed, stored on floppy or hard disk, or transferred over a computer communications network. Report and plot information includes, but is not limited to, average, standard deviation and failure tallies.


All Baker WinAST static motor analysis systems feature a standard control console, safety interlock switch and alligator clip terminations (unless optional custom fixtures are requested). A wide variety of single and dual station fixtures are available. In addition, test fixtures can be custom built to winding specifications. For more information concerning fixtures, contact your SKF representative.

High voltage WinAST option

A high-voltage version of the Baker WinAST is available for testing low-inductance form coils and motor stators of greater than 500 kilowatts or greater than 575 VAC. See specifications for particulars of this instrument.