2008 Polaris ATV Sportsman 300 400 H.O. Service Manual, Page 208Get this manual
ELECTRICAL Charging System Alternator Tests
Three tests can be performed using multimeter to determine the condition of the stator (alternator)TEST 2: Resistance Value of Each Stator Leg to Ground 1Measure the resistance value of each of the stator legs to ground: W1 to Ground, W2 to Ground, W3 to GroundEach test should measure: Open Line (OL) Test Battery Charge Coil Connect Meter Leads To: W1, W2, or W3 to Ground Ohms Reading Open Line (Infinity)
NOTE: Any measurement other than Infinity (open) will indicate failed or shorted stator legW1 W2 W3
TEST 3: Measure AC Voltage Output of Each Stator Leg at Charging RPM 12Set your voltohm meter to measure AC VoltageDisconnect the 3-wire stator connector near the voltage rectifierregulatorStart the engine and let it idleWhile holding the engine at specified RPM, separately measure the voltage across each leg' of the stator by connecting the meter leads to the wires leading from the stator (W1 to W2, W1 to W3, W2 to W3)Refer to the following table for approximate AC Voltage readings according to RPMTest each leg at the specified RPM in the tableExample: The alternator output reading should be approximately 18 VAC at 1300 RPM between each leg'NOTE: If one or more of the stator leg output AC voltage varies significantly from the specified value, the stator may need to be replacedRPM Reading 1300 3000 5000 AC Voltage (VAC) Reading 18 VAC 25 42 VAC 25 64 VAC 25