Melting switches

TimAustinTX
Posts: 30
Joined: Wed Dec 04, 2013 5:29 pm

Melting switches

Postby TimAustinTX » Mon Apr 03, 2017 5:27 pm

Hi,

I have a couple machines that have shown signs of heat damage to the main power switch. I swapped them but then they started to blow fuses.

Any ideas on what would cause this and a fix?

SWMS
Posts: 158
Joined: Mon Jan 06, 2014 4:28 am

Re: Melting switches

Postby SWMS » Mon Apr 03, 2017 10:04 pm

Something is drawing too much current which means something in your laser cutter that runs on 240/110v is probably faulty and needs/fixing/replacing.

It would be a case of measuring the amps draw by each component to see which one is being naughty.

Tech_Marco
Posts: 4388
Joined: Mon Jun 15, 2009 3:00 pm

Re: Melting switches

Postby Tech_Marco » Mon Apr 03, 2017 11:32 pm

@TimAustinTX: It shouldn't happen to 60W or smaller machine. I guess you have 80W or higher power laser, right?
Many laser exported from China has bad practice: use a single toggle switch to control the main power. Most of those switch can handle up to 8A current and for 80W, the max current may run at high as 9A. So, sooner or later the contact of the switch melt.

To solve this issue, either use a high current breaker (not switch) or use SSR.

Marco

TimAustinTX
Posts: 30
Joined: Wed Dec 04, 2013 5:29 pm

Re: Melting switches

Postby TimAustinTX » Tue Apr 04, 2017 10:54 am

Tech_Marco wrote:@TimAustinTX: It shouldn't happen to 60W or smaller machine. I guess you have 80W or higher power laser, right?
Many laser exported from China has bad practice: use a single toggle switch to control the main power. Most of those switch can handle up to 8A current and for 80W, the max current may run at high as 9A. So, sooner or later the contact of the switch melt.

To solve this issue, either use a high current breaker (not switch) or use SSR.

Marco



Thank you very much.

It's a "60W" machine but who knows.

Which SSR that you sell do you recommend?

Tech_Marco
Posts: 4388
Joined: Mon Jun 15, 2009 3:00 pm

Re: Melting switches

Postby Tech_Marco » Tue Apr 04, 2017 11:03 am

It seems that you have a very low quality or low current switches installed on your machines.
Any 25A SSR is good enough for your case.Get DC control, AC output type SSR and a small heat sink It take DC 3V~36V to operate. So, that you need one of DC power supply to be "ON" all times in order to get power for the SSR.

Marco

TimAustinTX
Posts: 30
Joined: Wed Dec 04, 2013 5:29 pm

Re: Melting switches

Postby TimAustinTX » Tue Apr 04, 2017 11:14 am

Tech_Marco wrote:It seems that you have a very low quality or low current switches installed on your machines.
Any 25A SSR is good enough for your case.Get DC control, AC output type SSR and a small heat sink It take DC 3V~36V to operate. So, that you need one of DC power supply to be "ON" all times in order to get power for the SSR.

Marco



So this SSR?

http://www.lightobject.com/25A-Solid-St ... t-P61.aspx
and
http://www.lightobject.com/Heat-sink-fo ... -P583.aspx

The AC adapter to power the SSR?
http://www.lightobject.com/Universal-DC ... -P232.aspx

I assume some kind of power switch like this to replace the old one?

http://www.lightobject.com/Red-SPDT-Pus ... -P531.aspx

Should I replace the e-stop too?

Tech_Marco
Posts: 4388
Joined: Mon Jun 15, 2009 3:00 pm

Re: Melting switches

Postby Tech_Marco » Tue Apr 04, 2017 11:20 am

The SSR, heatsink and the power supply are good.
I don't know much about your machine but I won't use that switch to replace the main power switch. Remember that the label of '5A' is the peak current and for a 60W laser machine, the overall power consumption could be as high as 700W or 7A.

Marco

TimAustinTX
Posts: 30
Joined: Wed Dec 04, 2013 5:29 pm

Re: Melting switches

Postby TimAustinTX » Tue Apr 04, 2017 11:27 am

Tech_Marco wrote:The SSR, heatsink and the power supply are good.
I don't know much about your machine but I won't use that switch to replace the main power switch. Remember that the label of '5A' is the peak current and for a 60W laser machine, the overall power consumption could be as high as 700W or 7A.

Marco



I have a couple machines that look like this (http://ebay.to/2nARd7s) but with the shorter laser tube.

They both have that same main power switch that melted. The e-stop melted on one of them too.

What do I need to buy to resolve this issue?

Tech_Marco
Posts: 4388
Joined: Mon Jun 15, 2009 3:00 pm

Re: Melting switches

Postby Tech_Marco » Tue Apr 04, 2017 11:34 am

A customer from Bay area who brought us that particular machine for service a couple times. Finally we couldn't do much because the laser headf and pulley got damage. It is very hard to get spare parts for that machine and the customer ended by a new machine from us.

Anyway, you can't use the E-Switch to turn On/Off the machine and that's how it was implemented. If you don't correct it, chance is that you may need to replace both switches every month!

Just use the E-Switch to control the DC power for the SSR that's all you need to do


Marco

TimAustinTX
Posts: 30
Joined: Wed Dec 04, 2013 5:29 pm

Re: Melting switches

Postby TimAustinTX » Tue Apr 04, 2017 11:39 am

Tech_Marco wrote:A customer from Bay area who brought us that particular machine for service a couple times. Finally we couldn't do much because the laser headf and pulley got damage. It is very hard to get spare parts for that machine and the customer ended by a new machine from us.

Anyway, you can't use the E-Switch to turn On/Off the machine and that's how it was implemented. If you don't correct it, chance is that you may need to replace both switches every month!

Just use the E-Switch to control the DC power for the SSR that's all you need to do


Marco


That makes a lot of sense.

So if take the e-stop out of the power line and install the SSR it should stop blowing fuses?

Tech_Marco
Posts: 4388
Joined: Mon Jun 15, 2009 3:00 pm

Re: Melting switches

Postby Tech_Marco » Tue Apr 04, 2017 11:45 am

Blowing fuse is another issue!!

Stupid things is the power voltage in China the power is 220V so if they put 5A fuse on your machine, then you need to put 10A if it is running AC110V now. You know how stupid those manufactures there?! That's why I always tell my customers do NOT touch those machine on Ebay even though it look like it is cheap. But it will ended up more to repair it because you don't know what are they selling. Good luck!


Marco

TimAustinTX
Posts: 30
Joined: Wed Dec 04, 2013 5:29 pm

Re: Melting switches

Postby TimAustinTX » Tue Apr 04, 2017 11:58 am

Tech_Marco wrote:Blowing fuse is another issue!!

Stupid things is the power voltage in China the power is 220V so if they put 5A fuse on your machine, then you need to put 10A if it is running AC110V now. You know how stupid those manufactures there?! That's why I always tell my customers do NOT touch those machine on Ebay even though it look like it is cheap. But it will ended up more to repair it because you don't know what are they selling. Good luck!


Marco


We did put a 10Amp fuse in there but they kept popping them after they run a few minutes. But this is after we had replaced the main switch.

Tech_Marco
Posts: 4388
Joined: Mon Jun 15, 2009 3:00 pm

Re: Melting switches

Postby Tech_Marco » Tue Apr 04, 2017 12:01 pm

:eek: May be the LPSU die already. Double checked it

TimAustinTX
Posts: 30
Joined: Wed Dec 04, 2013 5:29 pm

Re: Melting switches

Postby TimAustinTX » Tue Apr 04, 2017 12:09 pm

Tech_Marco wrote::eek: May be the LPSU die already. Double checked it


We are using 125V 10A fuses BTW.

Any pro tips on checking that LPSU? We can run it for maybe a few minutes now and then it blows the fuse but while its running it seems fine.

Tech_Marco
Posts: 4388
Joined: Mon Jun 15, 2009 3:00 pm

Re: Melting switches

Postby Tech_Marco » Tue Apr 04, 2017 12:15 pm

Only thing you may want to do is to get 12A fuse instead. It is a little strange that it blew a 10A fuse
You take the risk to scale up the fuse though

Marco


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