[Zeppelin1007]

Hey Guys,

Maybe another set of eyes on this issue couldnt hurt me here.

So I've been in contact with Marcus at geckodrive. Hes great help! Seriously. That guys is in too many places at once. Phone. Email. CNCZone lol. But, maybe some one else's views on this couldn't hurt. I'm scratching my head here.

Here's my panel layout. I left out the 5v control for now because I cant get past powerup without hellfire coming out of it!


Machine has been running great since October. Now I'm in Ohio and we've had some temp swings which caused some condensation in the shop. I waited days til after everything dried up to fire up the machine. She came up fine. Sat idle about 10 minutes. I plugged my USB drive into the pc and stepped back and BOOM! Sparks rained out of the control panel. Ok. Thats not good! My X and Y drives both had green OK lights (G201x's) the Z axis (G203v) said Fault.

I took all her guts inside. Tore through everything. Couldnt find where anything sparked. I mean these were big. ok. Test the faulted Z on a meter. Passes the Gecko test. Take faulted drive to work. hook it up on a 24vdc supply and all green.

Ok....Reassemble panel. Power up 120 -Check
Power up 74VDC - Check
Add drives (without motors) and powerup - sparks!

Dangit!

Only now i found where it came from this time. One of the screws on the back of the Y axis gecko arc'd to the heatsink. Uh. Why? Upon more inspection, it looks like my X axis arc'd to it either previously or just recently. The corner of the case of the drive is all charred.

Amazingly? I remove the drives from the heatsink and power them up one at a time on a different supply- no sparks. No faults. Now I was testing on a 24V switching supply at work.

I put it back in my system. Sparks.

Now, WHY did it start this after all these months? Could it have been the condensation? Possibly. But why wont it stop now?
Marcus over at gecko told me i should have my DC- tied to my AC earth ground. Ok. I dont doubt this. But why wont it stop going ballistic now? Yet one at a time I'm ok.

Leads me to bellieve:
-Ground loop?
-74v is too close to geckos limit? (its 80v and i was assured by Gecko I'm more than ok at 74v)
-Somethings wrong with my linear supply?
-These things really dont like the cold? My G540 Ive run in 0F temperatures just fine. Ive run this system around that temp before i got heat going.
-My mounting screws causing a gap between drive and heatsink?

What am i overlooking here guys?

Thanks a ton!

[mactec54]

Hey Guys,

Maybe another set of eyes on this issue couldnt hurt me here.

So I've been in contact with Marcus at geckodrive. Hes great help! Seriously. That guys is in too many places at once. Phone. Email. CNCZone lol. But, maybe some one else's views on this couldn't hurt. I'm scratching my head here.

Here's my panel layout. I left out the 5v control for now because I cant get past powerup without hellfire coming out of it!


Machine has been running great since October. Now I'm in Ohio and we've had some temp swings which caused some condensation in the shop. I waited days til after everything dried up to fire up the machine. She came up fine. Sat idle about 10 minutes. I plugged my USB drive into the pc and stepped back and BOOM! Sparks rained out of the control panel. Ok. Thats not good! My X and Y drives both had green OK lights (G201x's) the Z axis (G203v) said Fault.

I took all her guts inside. Tore through everything. Couldnt find where anything sparked. I mean these were big. ok. Test the faulted Z on a meter. Passes the Gecko test. Take faulted drive to work. hook it up on a 24vdc supply and all green.

Ok....Reassemble panel. Power up 120 -Check
Power up 74VDC - Check
Add drives (without motors) and powerup - sparks!

Dangit!

Only now i found where it came from this time. One of the screws on the back of the Y axis gecko arc'd to the heatsink. Uh. Why? Upon more inspection, it looks like my X axis arc'd to it either previously or just recently. The corner of the case of the drive is all charred.

Amazingly? I remove the drives from the heatsink and power them up one at a time on a different supply- no sparks. No faults. Now I was testing on a 24V switching supply at work.

I put it back in my system. Sparks.

Now, WHY did it start this after all these months? Could it have been the condensation? Possibly. But why wont it stop now?
Marcus over at gecko told me i should have my DC- tied to my AC earth ground. Ok. I dont doubt this. But why wont it stop going ballistic now? Yet one at a time I'm ok.

Leads me to bellieve:
-Ground loop?
-74v is too close to geckos limit? (its 80v and i was assured by Gecko I'm more than ok at 74v)
-Somethings wrong with my linear supply?
-These things really dont like the cold? My G540 Ive run in 0F temperatures just fine. Ive run this system around that temp before i got heat going.
-My mounting screws causing a gap between drive and heatsink?

What am i overlooking here guys?

Thanks a ton!

Try Grounding the Heat sink

[RCaffin]

The heatsink is meant to be anodised to provide the required insulation. Sometimes the anodising fails. Photograph the arc marks and ask for a replacement. It is a known problem. I had it once, and it was replaced in 24 hours. Marcus supports his products.

See arc marks at red arrows.

Cheers
Roger

[Zeppelin1007]

Hi Roger,

Yup thats the transistor thats now blown.

So heres what i did:
Plugged one drive in - The drive that arc'd. It was fine. No motor. Nothing.

Mactec i did ground it for this last test. Same result.

Ok. Added a second drive and kaboom to the first drive. Blew out a capacitor and the same transistor you have shown here.

Can you clarify this for me a bit Roger? So the anodization is supposed to isolate the back? I only ask because when i mount em, i usually end up dinging up the hole mounts where the screws go and exposing the bare metal. Is this causing it?

Ive not heard of this issue but i'd love to know thats all it is!

Thanks!

[RCaffin]

Sorry - can't help much.

When the drive faulted it tripped out the magnetic breaker on the supply line - several times. So I knew there was a problem. Having a separate breaker in each supply line is a wonderful idea. The drivers can handle a significant current overload for a brief period, but they are protected against an excess by the fast breakers.

I took a physically closer look at the drive, and I think I smelt it. With 40+ years in electronics, I recognised the smell and pulled the driver out of the chassis and opened it up. Once I saw the problem (per the photo), I simply contacted Peter Homann, local agent from whom I had bought the drive, sent him a photo, and he posted a replacement that day.

I THINK the black base is meant to be insulated so the devices themselves don't need mica washers. Either that or the devices would have to be internally insulated, and I doubt that would be so for these power levels. I might be wrong.

Cheers
Roger

[Zeppelin1007]

Hi Roger,

Where did you add these breakers? AC side? DC Side? only asking since they advise highly against putting on the DC Side, but i'd like to add some form of protection to mine.

Heck I'd add the mica washers myself if you told me thatd prevent it altogether.

Thanks Roger

[RCaffin]

Hi Zeppelin

The motor PS is just a big transformer, bridge and cap. That is in fact what 'they' all recommend for the drivers.
The breaker goes in the line from the cap to the driver. If the driver tries to pull more current than it should the breaker trips.
There is no harm in having a breaker in the DC power line if it only interrupts the supply. Don't use it to turn the supply to the driver on: that makes too much of a sudden slam.
I use some Tyco W28 series resettable thermal breakers (not magnetic ones as I thought), but anything like that would do.
Attachment 386748
You can see them to the right of the XYZ labels, under the ammeters. The drivers themselves are visible below that.

Dunno about adding mica washers - could do of course, but poorer heat sinking. With Gecko units you are much better off just asking for a replacement. Very good company.

Cheers
Roger