How to Attach Ring Terminal Crimps to PCB?

[sean0118]

Hi everyone,

What's the correct way to attach crimped ring terminals (Is that the right name?) to a PCB? For high-current, low-voltage applications a lot of the terminal blocks are physically oversized as they are often rated for 1kV.

Is it acceptable to bolt the ring terminals with some washers directly to a pad on the PCB? Or is there a large danger of the copper stripping off the board?

    

[mikeselectricstuff]

An issue is that PCB will cold-flow over time, reducing  contact pressure.
use something like this
http://www.toby.co.uk/content/catalogue/products.aspx?series=PCB-11-xxx

[RobertHolcombe]

I've not seen ring terminals used in the way you suggest, rather spade terminals are used as there are PCB mount male spade terminals.

[T3sl4co1l]

I've done it before, but as Mike says, PCB will shift.  Be sure to use cone (Belleville) or wave washers rated for a good amount of spring force.  Multiple in a stack if necessary.

Tim

[sean0118]

Ok, thanks guys, I'll play it safe and use one of the terminals Mike linked to. 

I've not seen ring terminals used in the way you suggest, rather spade terminals are used as there are PCB mount male spade terminals.

Hey, I'm not sure exactly which terminals you're referring to? Is it the quick connect crimp terminals you see in consumer electronics etc?

[nanofrog]

The AMP/Tyco 63849-1 would be an example of a PTH Quick Disconnect. 

[sean0118]

Ok thanks, those are the type of terminal I thought he was referring to.

Something else I just thought of, which of the two terminals mentioned in this thread have the lowest risk of shorting to another terminal? This is for a battery charger so I really do not want a short across the output terminals. Maybe, I should also use an inline fuse to protect against such a fault (as opposed to PCB mounted fuse)?

[cs.dk]

At work we use some like these; http://www.digikey.com/product-detail/en/7461383/732-3216-ND/2682507
You can get them in female thread to; http://www.digikey.com/product-detail/en/7460307/732-3201-ND/2682492

They seem to be fairly strong and reliable.

[nanofrog]

Something else I just thought of, which of the two terminals mentioned in this thread have the lowest risk of shorting to another terminal? This is for a battery charger so I really do not want a short across the output terminals. Maybe, I should also use an inline fuse to protect against such a fault (as opposed to PCB mounted fuse)?

Why not use fully insulated female spade terminals on your wiring then?

[sean0118]

Yeah I think I might, those screw terminals (and my original idea) look pretty susceptible to shorting. 

[woodchips]

As mentioned, the cold flow of the PCB is a killer, but it is worse than that. If you just screw the terminal to the board, and the PCB will prevent the correct torque being applied then the joint will get warm. At 120 deg C the PCB passes its glass transition temperature when it becomes like a stiff paste. This will not help the long term reliability of the joint.

If you screw terminals to a PCB always use Belville washers. Flat, crinkle and all types of shakeproof washers are a waste of time.

How do I know? Repairing and scrapping all types of electronics.