A new polyglass banding tape

Polyglass banding tapes consist of parallel, non-woven, twisted and high tensile strength glass yarns that are pre-impregnated with a special thermosetting resin; the resin employed permits long self life in the semi cured tapes. The tape has replaced steel rope in large DC rotor, commutator banding and transformer leg locking to minimize eddy current, over-heating and flashover etc. The thermosetting resin has an important role in the performance of polyglass banding tapes. A new polyglass banding tape was developed with a very special thermosetting polyester resin modified with organic silicone compound. The mechanical and electrical properties of the cured banding tape were thoroughly evaluated. Special test rings were fabricated from this tape to measure the moisture resistance by the effects of immersion in boiling water on tensile strength. The accelerated thermal aging test on the flexural strength of the tape was done and the Arrhenius type plot of logarithm of time vs. inverse of absolute temperature to 20000 hours line gave its temperature class. It was observed that the new polyglass banding tape had very high thermal stability (over 220degC) as well as an excellent humidity resistance. The cured structure was a homogenous laminate with smooth, resin rich surface that offered excellent track and arc resistance. The silicone modified polyester based glass banding tape is expected to be suitable for motor and transformer operating in a tropical environment as evidenced from the sufficient resistance to moisture