RE: Slotted Busbars.
Dear Group, Thank you all again for you help in this issue. I have since found out that one of the Engineers I initially contacted was in fact working on a customer's site. For this reason he was unable to respond to my initial request for information. It was therefore perhaps unjustified, not to mention unproffessional, for me to imply that his company had given me a poor service. I would therefore like to take this opportunity to apologise for including this unfair remark in my original e-mail. Best regards, David Sproul, Alexander Lynn Approvals Management, Tel/fax +44 (0) 1383 85 Mobile +44 (0) 7950 744466
Slotted Busbars.
Dear Group, thank you all for you speedy but varied answers. Best regards, David Sproul,
RE: Slotted Busbars
I cannot say if it is acceptable, because I am not sure what your particular criteria for acceptability is. But I can say that there is no problem technically. In the company I previously worked for, we designed and made telco rectifiers (basically they are honking big 48V battery chargers). Each rectifier outputted 10KH, and there were 11 of them per rack cabinet (for a total of 110KW per cabinet). At the top of each row of cabinets there was a pair of rather large bus bars connecting the outputs of each cabinet in parallel. I'm not talking about a puny 400A here; average continuous current was 10,000 A, and peak current could reach 100,000A for a short time when clearing a fuse (in this case the batteries under charge supplied the current peak). The bus bars were all laminated from thinner material (1/4 thick x 6 wide copper bars). They were peppered with obround holes (i.e. slots with rounded ends) to make bolt alignment easier. There was no problem at all, nor can I imagine why there should be. The only problem I can possibly see would be if rectangular slots (with sharp corners) were used. I could see someone complaining about this causing stress concentration and possibly being a start for crack generation. But I doubt that this is the problem you are referring to, since only a rank amateur mechanical designer would use a sharp-cornered rectangular slot for bolt clearance. Bob Wilson TIR Systems Ltd. Vancouver. -Original Message- From: David Sproul [mailto:david.spr...@alexanderlynn.co.uk] Sent: June 21, 2002 2:12 AM To: EMC-PSTC Subject: Slotted Busbars Dear Group, I have a client who wishes to use open slots instead of closed holes for the connecting bolts used in joining two 400A busbar within their product. This decision was taken to make installation and maintenance easier. However, their installation Manager has objected to this without giving a reason. I have e-mailed my contacts within TUV and UL, and after some 48 hours they have not responded. Are there any sufficiently knowledgeable people who can tell me whether or not this is permissible, and why. Best regards, David Sproul.
RE: Slotted Busbars
David Can not say if there is any reason in a standard against using open slots. But do understand the reason for not using open slots. A hole will give a very positive lock between the parts, ensuring they are correctly mated holding it in place and do not move over time. An open Slot has a greater scope for the bus bar to be inadequately installed in the first place, and more prone to movement over time. At 400A it will only take a little increase in contact resistance before the whole thing overheats and ignites. Without looking very closely at the application, fastening method and maintenance procedures. My past experience would be a very definite no to open slots for parts carrying 400A. Andrew Carson - Senior Compliance Engineer, Xyratex, UK Phone: +44 (0)23 9249 6855 Fax: +44 (0)23 9249 6014 -Original Message- From: David Sproul [mailto:david.spr...@alexanderlynn.co.uk] Sent: 21 June 2002 10:12 To: EMC-PSTC Subject: Slotted Busbars Dear Group, I have a client who wishes to use open slots instead of closed holes for the connecting bolts used in joining two 400A busbar within their product. This decision was taken to make installation and maintenance easier. However, their installation Manager has objected to this without giving a reason. I have e-mailed my contacts within TUV and UL, and after some 48 hours they have not responded. Are there any sufficiently knowledgeable people who can tell me whether or not this is permissible, and why. Best regards, David Sproul.
RE: Slotted Busbars
David Hello! Open slots or is ok if you have to fixing means (such as bolt and lock washer) for the connection. This is similar to fork type crimp connectors which have been acceptable by UL,TUV and other test agencies. Please note that some test agencies including UL and TUV do not like the fork type connections if relied upon for earthing and/or earth bonding connections. You may wish to discuss with these agencies when you use an open-slot connection for earthing/bonding connections. Best Wishes, This e-mail message may contain privileged or confidential information. If you are not the intended recipient, you may not disclose, use, disseminate, distribute, copy or rely upon this message or attachment in any way. If you received this e-mail message in error, please return by forwarding the message and its attachments to the sender. PETER S. MERGUERIAN Technical Director I.T.L. (Product Testing) Ltd. 26 Hacharoshet St., POB 211 Or Yehuda 60251, Israel Tel: + 972-(0)3-5339022 Fax: + 972-(0)3-5339019 Mobile: + 972-(0)54-838175 http://www.itl.co.il http://www.itl.co.il/ http://www.i-spec.com http://www.i-spec.com/ -Original Message- From: David Sproul [mailto:david.spr...@alexanderlynn.co.uk] Sent: Friday, June 21, 2002 11:12 AM To: EMC-PSTC Subject: Slotted Busbars Dear Group, I have a client who wishes to use open slots instead of closed holes for the connecting bolts used in joining two 400A busbar within their product. This decision was taken to make installation and maintenance easier. However, their installation Manager has objected to this without giving a reason. I have e-mailed my contacts within TUV and UL, and after some 48 hours they have not responded. Are there any sufficiently knowledgeable people who can tell me whether or not this is permissible, and why. Best regards, David Sproul.
Slotted Busbars
Dear Group, I have a client who wishes to use open slots instead of closed holes for the connecting bolts used in joining two 400A busbar within their product. This decision was taken to make installation and maintenance easier. However, their installation Manager has objected to this without giving a reason. I have e-mailed my contacts within TUV and UL, and after some 48 hours they have not responded. Are there any sufficiently knowledgeable people who can tell me whether or not this is permissible, and why. Best regards, David Sproul.
