UPDATE 1-Trina Solar top estimates, trims revenue forecast

* Trims full-year sales, margin forecasts

* Third-quarter earnings top analysts' forecasts

* Revenues rise 252 percent to $290.7 million

NEW YORK, Nov 19 (Reuters) - Chinese solar company Trina Solar Ltd (TSL.N) reported sharply higher quarterly earnings on Wednesday but trimmed its full-year sales and margins forecast because of the poor economic conditions.

Third-quarter net income was $32.1 million, or $1.17 per American Depositary share, compared with $7.8 million a year ago.

Wall Street analysts, on average, had been expecting earnings of $1.10 per share, according to Reuters Estimates.

Revenue was $290.7 million, slightly topping the $289.9 million that analysts had expected.

The Changzhou, China-based company cut its full-year revenue forecast by $50 million to between $800 million to $850 million and its module shipments to between 200 MW to 206 MW from its previous forecast of 210 MW to 220 MW.

The company's third-quarter gross margin of 22.4 percent fell short of its forecast of 23 percent to 25 percent as costs for polysilicon weighed.

Trina has said gross margins should improve next year due to a sharp drop in the cost of polysilicon, the solar industry's key raw material.

Since Oct. 1, Trina's shares have lost about 70 percent of their value as the global financial crisis and tumbling oil prices have tempered investor demand for renewable energy stocks.

Sales of solar panels have risen sharply in recent quarters as companies such as Trina have ramped up production of the clean power source. Tightening access to credit and a pullback in government subsidies in key markets such as Spain and Germany, however, have sparked concerns that an oversupply of solar panels will send prices tumbling and hurt manufacturers' profit margins. (Reporting by Matt Daily; Editing by Steve Orlofsky)