Qǐng dào sān hào xíngli chuánsòngdài lǐngqǔ nín de xíngli.
Please pick up your luggage at carousel number three.
Tips
usage
Standard airport terminology. 传送带 by itself is the generic 'conveyor belt' used in factories or supermarkets. Casual speakers may also say 行李转盘 - 'baggage turntable.'