Marcin, Group,Long ago, when Methuselah was a boy, I worked for Simms Motor Units in the development labs. Although not personally involved, Simms made starter motors for diesel engines. One of the specifications was the "locked armature current draw" which was the current that the starter would draw from the battery if the motor would not turn and is the maximum current the motor would draw except under fault conditions. In fact the starter was not designed to stand this sort of abuse, for that is what it was, for more than 10 seconds continuously.
However, if you can find this figure - sometimes given in detailed service/testing information, that is figure that the starter circuit should be fused at. I have had a brief search of the net for Dynastart info. with no success. One type of 3.5 inch starter fitted to small car diesels is rated at 720A locked armature and that may be a good starting figure. My engine manual (Beta BZ482) suggests a cranking current of around 400A.
The simple rule is that there is no simple rule. Geoff#################################################Geoff Blake, G8GNZ JO01fq: Chelmsford, Essex, UK
geoff@... or melecerties@...Using Linux: Ubuntu 11.04 on Intel or Debian on UltraSparc
and Apple OS X 10.8.2 Mountain Lion on my Macbook Pro. Avoiding Micro$oft like the plague.#################################################
