[stude8]

Recently we purchased a new Genos 300 with live tooling. Our distributor sent in their men to setup and train us. No problem with that and the machine is ok for what we plan to run on it.
Here's the problem. In the same room we have (2) LC 40's, (3) LC 20's, and (2) LC 20 4 axis machines. Also a bunch of verticals and horizontals. The problem is we can't run the other Okumas at the same time as the Genos because the spindle and axises go crazy when the Genos spindle is running. In fact when the Genos spindle ramps up and down the other Okuma spindles can actually even reverse. (showing no alarms BTW)
At first I thought we were having spindle drive and axis drive problems, but when each and every one had the same problem we knew it was the Genos.
Well the Okuma people said we needed a transformer on the Genos so we put a transformer there. It made absolutely NO difference. Then they said we need an earth ground so we put in a 8foot grounding rod. It made absolutely NO difference.
The weird part of it is we can run our Hitachi Seiki verticals, our Matsuura horizontal and our Mori Seike horizontals unaffected. They have both AC drives and DC drives.
Have any of you guys run into this before? I'm at a loss and not getting any help from the factory at this point. I really don't want to return the machine but...
Thanks for reading.

[cncts11]

They probably figured that adding a transformer would isolate transients that might be coming form the other machine to the ones being affected; the ground rod was to be sure you were properly grounded (however, you should never run two separate grounds; either use the ground rod, or run a ground wire back to the panel but not both). In any event, I've had a few customers with a similar situation; off the top of my head, I'd say it sounds like an internal"grid"/line impedance issue might be at work here. Okuma is notorious for dumping the regen. voltage to line; we would always test this on a new install as follows: measure the incoming three phase going into the machine with the spindle at rest. While your meter is still hooked up, ramp up the spindle to max rpm (or thereabouts) and notice how much the voltage drops during acceleration. Keep the spindle running, the voltage reading on the meter should stabilize and then hit reset to stop the spindle, and see how much the voltage rises. If you are getting more than 2-3% swings from normal, the impedance is probably too high on the incoming line (we would actually have to lock the machine out and would not continue the install until the customer changed his incoming service). Now, here is where it gets interesting: if your service in your shop is relatively small (meaning your internal"grid" is small), then these voltage swings can start to affect other machines. How I figured this out at one of my customers was I was measuring the incoming power on one machine and had him ramp up the largest spindle in the shop, which happened to be about 3 machines down the busbar line. He ramped it up and my incoming went from 208 to ~195v; then when he reset that spindle my voltage shot up to over 225v while it was decelerating. Now, this may not be the issue in your case at all, but it is definitely worth checking the incoming voltages on some of your equipment while the spindle on that equipment is running, and then also check it while the Genos is ramping up and down.

[stude8]

Thanks for you response. I will check the voltages tomorrow.
I do have a question about the grounding. Yes we have a ground rod And a ground wire going back to the busbar which you indicated wasn't a good idea. However if I disconnect the ground to the busbar aren't I still grounding through the conduit? Also don't I need that ground wire for Code reasons?

[cncts11]

Regarding the grounding: although this seems to be a hotly debated issue (regarding what is acceptable, what isn't, what is better: rod or wire, etc.) the issue involving running two different grounds is the potential for ground loops caused by multiple grounding sources (between the ground rod at the machine and the one that is at the electrical panel for the building). Personally, I like the wire run back to the panel, as the soil around here can be too sandy or rocky, etc. which has caused issues with the single ground rod at the machine being inadequate (which then leads to potentially unsafe conditions as well as susceptibility to noise and other transients). However, if the wire runs from each machine are installed incorrectly (for instance, where the grounds are "daisy chained" back to the panel), that is also a recipe for trouble.

The truth is, I highly doubt the grounding is your issue at all...my guess is you will find that the voltages are fluctuating considerably as the regen voltage from the other machines and those generated by the Okumas are overwhelming the internal grid you have there.

[underthetire]

Ive seen okumas blow out computers in business parks from decel. One customer showed me his power meter spin backwards! They are the only ones that seem to do it..,

[Algirdas]

building installation and nothing else. I have seen a lot of crazy PFC solutions. Effective and proper PFC is when capacitors are located next to problematic coil. Chasing for cheap and because of the lack of knowledge many owner install PFC on the input of building.
Powerfull intelligent PFC for Genos can help a little. Every machine needs intelligent PFC in case, if building installation cannot be fixed.

[stude8]

The voltages do not vary more than a volt or 2 when the spindle is ramping up or down either on the Genos or the other machines.
I heard from Okuma and they think it's a noise filter problem and will send a tech in with a scope in a week. I appreciate all your posts and will report the solution when it occurs.

[Algirdas]

it's not a voltage problem. phase. You need to check cos ɸ. Power factor register is necessary for that. Doesn't matter really, because the solution is only reconstruction of factory installation. On the basis of your comments I suspect another cause of problem. Check if installation in your factory is not redundant. Check the neutral. You need to have factory installation schematics. Maybe there is loop in neutral or some other "magic"

[cncts11]

"The voltages do not vary more than a volt or 2 when the spindle is ramping up or down either on the Genos or the other machines.
I heard from Okuma and they think it's a noise filter problem and will send a tech in with a scope in a week. I appreciate all your posts and will report the solution when it occurs."

OK, so it sounds like your line impedance is good and your grid is capable of distributing the regen voltage dumps...Curious: what is the voltage coming into the machine? Is the service in your shop 120/240 delta (which would have a wild leg)?

[kawarta]

i did request help to okuma and they sent me comments i am attachhing those like a pdf

[cncts11]

Recommendation #1 is often overlooked - customers assume that they have enough physical room to add more equipment so they do, without regard to the capacity of their service when all the loads are running at once. Definitely do the total calculation and see where you are compared to your overall capacity. Recommendation #2, 3 and 4 is what some of us were referring to regarding the regeneration voltage issue. However, since you have stated that the voltage variations are minimal (I assume you were checking between phases), then it seems this wouldn't be the problem (when it is a problem, then the isolation transformer/line regulator works very effectively to isolate the voltage swings from the "grid" in your shop). I would follow the checks here that they are outlining and get back to them...curious to see what it turns out to be.

[stude8]

Last week an isolation transformer was installed. I want to thank the people at Okuma and the people on this board for their help and advice. Today we ran 3 older Okumas with the Genos with no spindle or axis problem.