Do đó góc là phổ biến hơn thể hiện trong điều khoản của GAP mỗi đường kính. Khoảng cách riêng của mình là không có ý nghĩa, nó phải được chia cho đường kính để có ý nghĩa. Đường kính là chính xác được gọi là một "đường kính làm việc", nhưng thường được gọi là một đường kính khớp nối. Đường kính làm việc có thể được bất kỳ giá trị thuận tiện. Đó là mối quan hệ giữa khoảng cách và đường kính đó là quan trọng | Troubleshooting Coupling strain and shaft deflection New readings do not agree with moves just made When performing an alignment whether using dial indicators or laser optical systems sometimes the readings following an alignment adjustment do not agree with the corrections made. One possibility is that coupling strain is deflecting the shaft the machine mounts or the foundation. This has frequently been noticed particularly on pump sets which have a front steady mount as shown in the following sketch. In this application the flexible coupling element is radially quite rigid and can influence the alignment measurement. In this situation we advise splitting the coupling element to free the measured alignment from such external forces. If not accomodated the net effect of influences such as noted above is that the new alignment is not only wrong but quite often has been made in the opposite direction to the required alignment correction. In extreme cases coupling strain imposed by the newly aligned machines can bend shafts during operation. In most cases this bending will be minimal but sufficient to affect the measured axes of shaft rotation. The following sketches illustrate the potential problem. 21 2002 PRUFTECHNIK LTD. Troubleshooting This is the alignment condition with shafts uncoupled This is the measured alignment with the shafts coupled. Projected centerlines of rotation are shown The moves are made as measured. There is less strain on the coupling now and the shafts can be properly aligned at the next attempt. 22 2002 PRUFTECHNIK LTD. Causes of machine breakdown Couplings can take misalignment An often quoted comment is .why bother to align the machine when it is fitted with a flexible coupling designed to take misalignment Experience and coupling manufacturers maximum misalignment recommendations would suggest otherwise. Anecdotal evidence suggests that as much as 50 of machine breakdowns can be directly attributed to incorrect shaft alignment. It is true
