SX3 E-Stop Faulty

[neilw20]

If the relay clicks, then it looks like it is not working properly.
It sounds like you use the ES a lot.
The relay in question is rated at quite high current, but my experience with that particular style of relay has shown it to be unreliable when switching a high current. In normal operation were it is on all the time, at high current, the contacts can become quite hot. The trouble occurs when a high current is switched. I have only ever used my ES switch in anger, and have no reliability problems. I think your relay has welded contacts.
The ES should still stop Mach3, and if so it almost surely welded contacts.
WITH THE POWER UNPLUGGED and REMOVED, measure the resistance (ohms range) between the horizontal tab on the wide track (rectifier leg) at the top left of motor pcb, and the top of the fuse holder. If it measures between 1 and 2 ohms, the relay is shorted. If while measuring shorted, you hit the relay with a plastic screwdriver handle it will probably become unstuck.

It would appear like you use the ES a lot? Was it really an emergency?

neil

[Ed from NY]

Question... what you described, does it also apply when you invoke a ES from Mach3 or is it only when pressing the button on the machine???

Thanks!

[SDesigns]

Hi Neil,

I only have a problem if I hit the button on the front of the machine. If I hit the ES (reset) from Mach3, the machine does stop.

The Red ES mushroom does not stop or reset mach3 though. Still think it could be welded contacts on the relay? I think not, because if they were, I wouldn't hear it switch.

I don't use the mushroom often at all. I mostly use it just before I switch off the machine. In over a year of owning the machine, I can proudly say that I have never broken a tool. Apart from switch off, I hardly ever use the shroom.

Interesting that the mushroom doesn't reset mach3?

[iGG1e]

The Red ES mushroom does not stop or reset mach3 though. Still think it could be welded contacts on the relay? I think not, because if they were, I wouldn't hear it switch.
?

I had the same problem and the relay contacts were welded. It freed after a sharp tap and for now I put a snubber across it to help before I contemplate changing it as it doesnt look like a quick de-solder job.

On the subject of the click, I've found in many relays the click isn't the contact faces making the noise as they move together, but it is the rocker mechanism that makes the click. This I've seen still move even when the contacts are fused in other clear bodied relays.

[Al_The_Man]

This I've seen still move even when the contacts are fused in other clear bodied relays.

This is very true, it is the relay armature that you can hear.
Any welding of contacts is aggravated if any DC currents are being switched, Most relays are very much de-rated if switching DC.
Al.

[SDesigns]

Oh ...... wait!!!!

I had a crash a while ago, where the spindle got buried in the nylon I was cutting. I hit the mushroom then - obviously! Is it possible that the damage to the relay was caused then? The spindle would have been under load when the shroom was hit. The spike from that would damage the relay right?

I'll take the back off again and try the screw driver tap thing.

Can I get a replacement relay?

Thanks for the help. I really appreciate it.

[Al_The_Man]

If it is controlling a spindle, I would pick up a contactor, they are built more for this kind of service with heavier duty contacts, ebay are a good source. Look for the more compact DIN style.
When switching a heavy DC current, it will more readily sustain and arc across a gap, the contact surface melts and then welds to the opposite contact.
Al.

[SDesigns]

Thanks Al, but I have no idea what a contactor is!

Is it a big job?

[SDesigns]

I measured the resistance as described by Neil in a previous post.
He was bang on! 2.6 ohms. WELDED!!!

I gave it a few taps with the handle of a screw driver, and it now works perfectly.

Thank you to every one for the assistance.

[Al_The_Man]

If it welded once, it should be replaced.
Contactor = Heavy duty relay.
http://www.eatonelectric.com.au/Prod...rs/modular.asp
Al.

[neilw20]

If it is controlling a spindle, I would pick up a contactor, they are built more for this kind of service with heavier duty contacts, ebay are a good source. Look for the more compact DIN style.
When switching a heavy DC current, it will more readily sustain and arc across a gap, the contact surface melts and then welds to the opposite contact.
Al.

In the X3 and X4 the relay is switching AC current, and is within it's normal ratings.

DO NOT put a contactor on the motor winding side. This is guaranteed to fry the electronics.

Just replace the faulty relay. That is all that is required.
If you want to find a better brand, use Zetler.
Make sure the COIL VOLTAGE is correct.
These PCB's have possible variations in the voltage spec for relay from country to country.
The relay:
http://www.azettler.com/index.php?id...product=az2850

[Al_The_Man]

In the X3 and X4 the relay is switching AC current, and is within it's normal ratings.

I would have thought that if a relay contacts weld together there is some potential for it happening again to the same component?
I would definitely use a better rated component.
From the R.O.C. electrical components I have seen so far they leave alot to be desired.

DO NOT put a contactor on the motor winding side. This is guaranteed to fry the electronics.

I am not sure I understand that one? Used with an R/C snubber on the coil, contactors are used all the time together with logic circuitry?
Al.