Resistance Test (End-to-End and Bar-to-Bar):
The resistance test reads all of the 180º resistance readings at each 180º pair of commutator bars. Every reading is compared to the internally stored low and high resistance limits. The ranges are .02-1000 ohms with a resolution of .0001 ohm on the 1 ohm range. The Series 6000 tester features ambient temperature compensation, which allows for fluctuations in the room temperature. Infrared temperature compensation is available as an option. Resistance readings are
compensated to 25° Celsius. Click here to view the set-up screen.
Resistance testing will detect errors such as broken wires, stretched
wires, open coils, wrong number of turns and wrong wire size.
ESW's surge test is far superior to the competition. We are able to stress the windings with a greater amount of energy, enabling the most sensitive of shorts to be detected.
A capacitor is discharged into the windings. The system monitors and
analyses the surge waveform by measuring the ringing
time and amplitude of the characteristics ringing
waveform. Voltage is adjustable from 0-3000 volts. Testing is performed in both forward and
reverse directions. Click here to view the set-up screen.
This surge test will reject windings and insulation faults such as shorts between windings and breakdowns between wires. It also detects incorrect turn counts, shorted
turns and improper connections.
Chips between the commutator bars can also be detected. If a chip is touching both bars, the weld and resistance tests will detect the fault. However, if the chip is wedged in and not touching both bars, ESW's surge test will detect this.
The Series 6000 testers perform both bar-to bar and end-to-end weld tests. The end-to-end test is the most accurate method of detecting armature weld flaws.
- End-to-end readings are scanned and the lowest and highest readings are selected. The readings are scanned and the deviations between opposite coil readings are compared.
- Bar-to-bar testing is useful on some hand-staked applications. The readings show wire size and stretch of one flyer versus the other winder flyer. Controlling the flyer and wire size variations will result in less need for balancing corrections.
If a weld reject is detected, the test will stop and the weld resistance and position of the commutator bar will be displayed. This insures that bad welds are detected regardless of their location. Limits as low as .0001 can be set on the 1 ohm resistance range
Weld testing detects armatures with open bars, poorly fused
commutator bar connections, out of limit welds, side-to-side electrical imbalances, winder and
wire tension device differences and different sized wire on opposite sides.
A hipot voltage is applied to the armature between the commutator, stack and shaft. The voltage is applied at the zero crossover point of the sine wave to prevent a voltage surge. The leakage current is constantly monitored and compared to the internal low and high leakage limits. If excessive leakage is detected, the hipot voltage is immediately removed to prevent further damage to the armature. Voltage is adjustable from 0-3000 volts; higher voltages are available as an option. Test time is adjustable from .1 to 10 seconds. Our hipot testing also features our exclusive hipot fault process. This prevents the armature from going through the test without an accurate hipot test being performed. Click here to view the set-up screen.
Hipot testing is used to satisfy regulatory requirements by detecting armatures with excessive leakage and breakdowns between the wire and the adjacent metal.
- Commutator Offset. (AKA: Bar Advance Testing.) Detects armatures wound in the wrong slot or connected to the wrong bar. No other test available can detect this type of winding fault.
- Secondary Hipot. Two hipot voltages are applied to the armature between the commutator, stack and shaft. Both voltages are applied at the zero crossover point of the sine wave to prevent a voltage surge. The leakage currents are constantly monitored and compared to the internal low and high leakage limits. This test is necessary when testing double insulated armatures.
- Low Resistance Armature Testing. ESW has developed a testing process specifically for low resistance parts. Due to the uniqueness of the process and properties of these parts, special methods are necessary.
- Corona Testing. The corona test is performed during the standard surge test. This testing method will detect the high frequency component on the surge discharge
waveform. No null adjustments or compensation are required. Corona can be detected on turn-to-turn , phase-to-phase and coil-to-core.