Design and Development of Endurance Test Unit for the Design Modification of Rom for the Safety Enhancement of the MCCB

Abstract

The Rotary Operator Mechanism (ROM) is an external accessory of the MCCB. This accessory's mechanism transforms rotational motion of ROM knob operated by the user into reciprocating motion of slider which drives the MCCB knob joined directly to the MCCB. It is a safety device for avoiding the direct contact with the MCCB which gives protection from direct contact with the MCCB terminals. When the MCCB experiences an overcurrent and the contacts get fused together, a feature with the operating mechanism of MCCB kicks in. The present MCCB mechanism is built and organized in such a way that the MCCB knob will always display the TRUE indication in this case. But due to lack of Forces inside the ROM, the ROM standalone is not capable to show the true indication of the MCCB with the PAD lock Safety feature of the ROM. This is serious problem with the current deign of the ROM. Hence the present work comprises of design of new mechanism of ROM to overcome the problem of ROM not showing the true indication with the PAD lock safety feature. With the use of static force balancing method equations are established to solve the existing problem with the ROM. In order to ensure the reliable and safe functioning of the new developed mechanism, a test set up has been designed & developed. The concepts are being developed for the endurance set up followed by concept selection. The design of the endurance test set up has been carried out. At present, the prototype development of the test set up is in progress. The new design of the ROM endurance test setup has resulted in no use of human intervention for operation. The endurance test set up developed is fully automated and does not require human intervention. The new design has also resulted in reduction of operation lead time from 16 – 24 hrs. To 8 – 10 hrs. For 50,000 operational cycles.