Home Page with Town List
Topics Topics Help/Instructions Help Edit Profile Profile Member List Register  
Search Last 1 | 3 | 7 Days Search Search Tree View Tree View  
This forum was closed 18 May '07 and transferred to here. The user database was not transferred - sorry, but you will have to register again.

Forum * 70. Control Systems * * Wiring "quality" < Previous Next >

Author Message
Top of pagePrevious messageNext messageBottom of page Link to this message

Gerald_D
Registered
Username: Gerald_d

Post Number: 113
Registered: 11-2005
Posted on Saturday, June 03, 2006 - 09:44 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

This thread is intended to discus the points that determine the "quality" of a control box....

To kick off, the following pics show a poor quality of connection:
2 2 2

The copper shouldn't be exposed outside the terminal by that much. A slip of a measuring probe could cause a short.

Good terminal blocks have deep separators:
5


Here is another terminal block that has good separation between the wires:
3


But the Gecko terminals are a bit too shallow and close for 80V 7Amp applications and I feel that the terminals shown below are needed:
4


These terminals are crimped with the following tool:
1

1
Top of pagePrevious messageNext messageBottom of page Link to this message

Steve M
Registered
Username: Stevem

Post Number: 4
Registered: 12-2005
Posted on Sunday, June 04, 2006 - 01:40 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

If you touch the exposed heads of the lock down screws on the terminal block, you also cause a short.
Top of pagePrevious messageNext messageBottom of page Link to this message

Gerald_D
Registered
Username: Gerald_d

Post Number: 114
Registered: 11-2005
Posted on Sunday, June 04, 2006 - 06:37 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Steve, have you noticed the big bare leads on the other side of that terminal block? They are the legs of the G202's internal capacitor.

The exposed copper I showed above is not serious, but it can get worse. For us guys with poor eye-sight, we can't easily tell when one copper strand has not entered the terminal properly and is threatening to visit its neighbour.

Some guys would "tin" the strands together with solder, but that practice is frowned upon by others. The crimped lugs are just so darned easy, but they take up space.
Top of pagePrevious messageNext messageBottom of page Link to this message

Gerald_D
Registered
Username: Gerald_d

Post Number: 115
Registered: 11-2005
Posted on Sunday, June 04, 2006 - 08:25 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Here are some more arguments for the crimped end terminations. At first glance, the wire on the left is fine, but on closer inspection it has a stray. When it is removed, it looks like a birdnest:

01L 01M 01R fr


A basic problem is that the strands of the wire are too fine - this happens when very flexible wires are used in panels


Another problem is that the stripping process easily cuts some copper away:

3L 3r


When a wire is removed from a teraminal, it should look as on the left. The right side version is messy and dangerous because the little broken strands fall into other circuits and cause shorts:

Healthy Sick

Broken strands after tightening is often caused by the type of terminal where the rotating screw rubs directly on the strands. Use better terminals of the "cage-clamp" type.

Twisting wires together before clamping in a terminal can work, but it mostly gets messy:

TwistOK Mid bad


The insulated crimp lugs solve a lot of these issues:

ZL ZR


A basic rule is that a maximum of 2 wires may be fitted to a terminal. And most times a pair of wires will only be properly clamped if:
- they are twisted together first, or
- they are exactly the same size and lie side by side.

The crimped pins in the last pic show that the pins are the same size even though the wires are completely different sizes. (The colour on the crimped pins give the wire size only).

Good wired joints can be disconnected and re-connected a good number of times without degrading the connection. An inspector will tug quite hard on a couple of joints and he will undo a few suspicious ones to see what is happening inside - any single failure and whole panel must be redone.
Top of pagePrevious messageNext messageBottom of page Link to this message

Mike Richards
Registered
Username: Richards

Post Number: 9
Registered: 05-2006
Posted on Wednesday, June 07, 2006 - 04:13 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

As someone who has worked on a lot of machines during the past thirty years, I can vouch for everything that you've posted, Gerald. Much of my work has been with Kodak design and built photo printers (S-series mainly). Kodak was famous for connecting everything via open terminal strips. At least they used crimped ring-style connectors; but, because the terminal strips were open, anything falling onto them, including dropped multimeter probes, destroyed things. When I started servicing European machines, particularly Durst and Gretag from Germany (at the time - both companies have changed hands and countries multiple times), I was amazed at the difference in wiring. The Durst and Gretag used the same practices that you've shown. They were neatly laid out. The 2.5mm DIN connection blocks were numbered. Scope and meter probes could be used without worry. Years ago, I copied them, except for the crimped lugs - which I'll start using immediately. After all, it's faster and easier to crimp something than it is to solder the exposed wires. (Maybe the lead in the solder is the real reason for my approaching insanity.}
Top of pagePrevious messageNext messageBottom of page Link to this message

Gerald_D
Registered
Username: Gerald_d

Post Number: 128
Registered: 11-2005
Posted on Saturday, June 17, 2006 - 04:17 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

The first check by an inspector is often the floor of the box. Any signs of copper lying there and the box is condemned on the spot.

Posed photos:

1 2
Top of pagePrevious messageNext messageBottom of page Link to this message

krymis
Registered
Username: Krymis

Post Number: 2
Registered: 08-2006
Posted on Thursday, August 17, 2006 - 04:59 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

what do you call the connectors used to wire into the gecko drives? Where would one find these?
Top of pagePrevious messageNext messageBottom of page Link to this message

Gerald_D
Registered
Username: Gerald_d

Post Number: 180
Registered: 11-2005
Posted on Saturday, August 19, 2006 - 06:19 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

BlockMaster DGPBP111 from www.blockmaster.com are the ones that Gecko now use (and supplied with each drive). Beware, there are also many generic equivalents, but you must ensure that they connect positively - a bad connection can blow the drive.

Add Your Message Here
Post:
Username: Posting Information:
This is a private posting area. Only registered users and moderators may post messages here.
Password:
Options: Enable HTML code in message
Automatically activate URLs in message
Action:

Topics | Last Day | Last Week | Tree View | Search | Help/Instructions | Program Credits Administration