Bad news for American Superconductor, the company that, despite its name, actually gets most of its revenue from its wind turbine parts and licensing lines of business and much of that from a single customer. That customer, China’s Sinovel Wind Group, has apparently “refused to accept” shipments of wind turbine components from AMSC, the company announced in an after-market Tuesday press release — and there’s no information from the Devens, Mass.-based company about why Sinovel has refused the parts, or whether it’s going to change its mind. AMSC now predicts its fourth-quarter revenues will fall to less than $42 million, down from analysts expectations of about $119 million. AMSC shares have plummeted from $24.88 to $12.88 in Wednesday trading, losing nearly half their value in the space of a few hours. What’s going on?Sinovel did hold the first quarter’s largest greentech IPO, raising 9.46 billion yuan ($1.4 billion) on the Shanghai Stock Exchange. China is known for “encouraging” its homegrown green tech industries by setting certain quotas and requirements for domestic sourcing of equipment and support services, and in March set certain minimum manufacturing and generation capacity benchmarks for any Chinese wind power seeking to expand — a move taken by many observers as a sign that the Chinese government wants to weed out the smaller of its 80 or so wind power companies to allow the biggest to better thrive against the international competition.