New user with Cosmo 170 (SIP) and a headache

[R Kraft]

Here's a SPDT automotive type.
http://www.the12volt.com/relays/relays.asp

 

[BChild]

Here's a SPDT automotive type.
http://www.the12volt.com/relays/relays.asp

Ahh so I need a 5 pin Relay................

Goes off to rummage

Back soon - I have a tote bin full of relays as spares

 

[BChild]

That one is a single pole, single throw.
You need a single pole, double throw.

Ta for this post and your one that follows - bear with me - I can just about wire a plug...........

 

[R Kraft]

Here's a little miller welder diagram,on page 31 , The CR1s on the M motor are the normally open and closed contacts.http://www.millerwelds.com/om/o1307b_mil.pdf

 

[BChild]

Rummaged - looks like I need to order one - I have several but only one has a schematic

Terminals underneath (labeled for clarity)

No 87a so I assume no use hence off to find one in the interweb

 

[BillJ]

Unless you have a 12V supply somewhere in your welder that's only on when you pull the trigger, you'll need a more suitable coil voltage than the 12V relays you're looking at. 24V is commonly available so you could wire it onto your new transformer. I used 240V (because I had one), wired across the input to the power selector switches. Better (safer) to stick to the lower voltage if you have to buy a relay anyway.

 

[BChild]

Unless you have a 12V supply somewhere in your welder that's only on when you pull the trigger, you'll need a more suitable coil voltage than the 12V relays you're looking at. 24V is commonly available so you could wire it onto your new transformer. I used 240V (because I had one), wired across the input to the power selector switches. Better (safer) to stick to the lower voltage if you have to buy a relay anyway.

Right of to google 24V SPDT Relay (Automotive)

Thanks to all

Looks OK?

http://www.maplin.co.uk/module.aspx?TabID=1&criteria=usb&ModuleNo=37526&C=SO&U=Strat15

 

[BChild]

Ahh Good old RS
Choice of just one with 24V and automotive type spades but I think it ticks all the boxes

http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=1782006

 

[R Kraft]

Looks like it will work.

 

[BChild]

Looks like it will work.

Excellent - unfortunately this means I will be asking further questions regarding the terminals to use



I do believe I've sussed the photo facility on this forum now FLW

 

[BChild]

Should have posted this too



So I've got 5 terminals 30, 85, 86, 87 And 87a

I've got 2 wires being fed to the motor unit and I can't for the life of me work out how to wire up a relay to do as described

 

[R Kraft]

I have to hurry to work.
So look close before you use this, #87 would be power from the speed control.
#87a would be on the Neg side of the motor with the ground wire.
#30 would be on the positive side of the motor alone.

 

[BChild]

I have to hurry to work.
So look close before you use this, #87 would be power from the speed control.
#87a would be on the Neg side of the motor with the ground wire.
#30 would be on the positive side of the motor alone.

Well I've had some help with this.........



Have I got it safe side of close?

85 and 86 Positve and negative sides of the coil (when the power is provided to the circuit the coil moves the switch)
30 = common connected to the positive of the motor
87a = Positive from the transformer
(the above two terminals are closed when relay is not powered up
87 = connect to negative side of the motor

It's a bit tricky it all depends on which of 87a and 87 are the closed positions on the relay I'll have to look at the relay when I get hold of it so it could be that I need to swap those about.

 

[R Kraft]

You just have 87 and 87a swapped.

 

[BChild]

You just have 87 and 87a swapped.

I did wonder



Credit given accordingly

 

[R Kraft]

When the motor is coasting it acts as a generator.
When the relay shorts across the motor it loads the motor/generator and makes it stop.
If it stops it too fast, you can use a resistor in series with your 87a lug to ground , to let a little more wire feed.

 

[BChild]

When the motor is coasting it acts as a generator.
When the relay shorts across the motor it loads the motor/generator and makes it stop.
If it stops it too fast, you can use a resistor in series with your 87a lug to ground , to let a little more wire feed.

Or a even a potentiometer to adjust the stick out

- nooooooo enough with the modificaerations



Ta for all you help and Bill too I've learnt so much in this thread

 

[Jake SS]

I did wonder

View attachment 9716

Credit given accordingly

Can you post the modified circuit as I cant see that this will work?

 

[BChild]

Can you post the modified circuit as I cant see that this will work?

Thats asking a bit much of my MSpaint skills

 

[BChild]

Ahh Good old RS
Choice of just one with 24V and automotive type spades but I think it ticks all the boxes

http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=1782006

Meh........... PCB Fitment Relay Arrived Friday

Phone call to RS customer service resulted in an alternative that I couldn't find on line being found and now on route to me - Good thing about RS is customer service

Looking at tuesday evening to see if I can get it wired in and see if it works