Checking Field Coils

Both field coils should be checked for open circuit, winding and earth shorts.


  1. Check each field coil separately for open circuit connecting its ends with a 12 V test lamp in series with the battery. In the case of open circuit the test lamp will not light up.
  2. Winding shorts can be checked by connecting the ohmmeter with the ends of each coil and comparing the test result with the recommended values (see electrical data). If an ohmmeter is not available one should connect a 12 V battery in series with an ammeter to the coil ends and should then compare the current intensity at the coils, If the current consumption difference between the two coils is greater than 0,5 Amps, the coil with the higher reading has a short circuit.
  3. One should check the coils for short circuit to earth by connecting a 40 V test lamp to one end of the field coil and the generator housing. The test lamp should not light up.
  4. The field coils should also be checked for satisfactory electrical and mechanical contact with each other.
Last modified: Mon, 17 Jan 2005


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