"Jürgen Spelter" wrote in message
...
Hi Mike,

measuring with an ohmmeter as you`ve done won`t bring any true result,
because the compressor is an electrical motor and has not only resistance.
With your method you should substract the values and you will get .4 ohms
as
the motor`s resistance. At 12 V voltage the current of that compressor
would
be 30 A. I don`t think, your compressor will have such a high current.

On startup, it will. Once the motor runs, it generates back-emf. The
difference voltage between supply and back-emf, divided by the internal
resistance, is the resulting current.

Meindert