Complex sentence: In 1867, Werner von Siemens described a dynamo without permanent magnets (independently invented also by Charles Wheatstone), and Siemens became the first company to build such devices.
Split into simpler sentences: In 1867, Werner von Siemens described a dynamo without permanent magnets. A similar system was also independently invented by Charles Wheatstone, but Siemens became the first company to build such devices.