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1987 LB could have a VACA drive, or a Fanuc drive. Please specify. VACA drive alarm on decel ? What alarm? voltage flutter alarm? OVC alarm?
Hi everyone, I run a 1987 model lb-15 that recently fried several resistors in the sdu. unit was rebuilt locally and replaced, however now anytime I run over 500 rpm or at any rpm in low gear, the machine shows SDU ALARM. The person who rebuilt unit had casually asked me at one point if I knew the dip switch settings on the top board. when I asked why he told me he was sure they didn't get changed but just wondered if they could be confirmed. Local Okuma reps say my company would have to let them check it out and if switches are wrong only okuma can tell me what they are, as this is proprietery information. shortly after this the power unit and transformer both died and were replaced, I am wondering if they could have been spiking board and caused problem in the first place. can still run in high gear at 500 rpm or less, but had to set rapid parameters down to keep from alarming out on long csf facing operations. Braking resistors test perfect and our own maintenance chief has tested everything he can with no explanation.
If this is a dip switch error, how dangerous is it to just try random settings?
There are four sets of switches, two side by side with 4 toggles each, and two side by side with 8 toggles each. I believe it was the 8 toggle he was refering to. the banks of 4 are set the same on/off pattern, while the banks of 8 are different. I have taken a picture of the board as they are now. unfortunately I was on vacation when they had sdu removed so noone thought to take a picture before removing it. If I found another lb-15 with the same motor and sdu would the settings possibly be valid? I run3 okumas in a department consisting of this machine, a 2002 Captain l370 and a 1982 4-axis lc30, which has a few quirks of it's own, so having limted capacity on this machine is killing our production schedule. Any ideas would be greatly appreciated Thanks
1987 LB could have a VACA drive, or a Fanuc drive. Please specify. VACA drive alarm on decel ? What alarm? voltage flutter alarm? OVC alarm?
It is a VAC A drive, The alarm is simply SDU alarm 201.
book describes as faulty sdu with no explanation codes.
It probably is a bad drive, regen circuit would be my guess. Those drives are NLA, and would need the $$$$upgrade$$$$. I've never had any outside companies able to succesfully rebuild any Okuma motors/drives. Some say they can, but i've never seen one work.
Thanks for reply. any idea on how i can check the dip switch settings? I would not suspect them at all if tech who worked on unit hadn't brought it up. It wasn't even after new problem came up, he asked if i knew them before re-installing the drive. And would regen circuits work at one rpm but not another? I'll keep using machine as long as it spins anyway. an okuma at 1/4 capacity is still better than nothing.
I don't have anything for the A type. Okuma would have it. I do however need to ask if you have a line transformer on the machine? The decel problem 99% of the time was from high impedance supply transformers, I have seen this for years, but usually you get a Voltage Flutter alarm. Also, did the spindle motor get a mega ohm check on it?Originally Posted by krusty
There is a transformer connected to sdu that burned up and was replaced after rebuild, but also after decel problem started. Our in house electricion installed it. There is also a step down transformer integral to machine for connection to 440 0r 220 systems, I know the input and output were checked on this unit as well. I believe the motor was tested when sdu went down initially, but I was on vacation at the time so I am not sure which tests were done. here is what I do know; In sept. the sdu alarm came on and would not clear, I was leaving the next day so my company called in a machine repairman we have used in the past. He discovered several dead capacitors in sdu and took to his shop to rebuild. When he returned with it he asked about the switches before even reinstalling it, which is why I have concerns that they were changed. After hooking it back up, machine ran but would give sdu alarm when spindle was stopped or slowed down, unless machine was in high gear and running at 500rpm or less. the next day he returned to troubleshoot the decel problem and power supply was dead, He replaced that with closest match available and machine ran with decel problem still happening. I ran that way for about a month and transformer burned up(literally caught fire on start up one day).
Our electrician replaced with similar unit and drove himself nuts for the last month or so trying to solve problem. when transformer was replaced on first powerup machine worked with same decel prob for a few minutes and I spotted smoke coming from top board so killed main power, board was sent out and tested and a short was repaired. According to bench test is functioning properly, but still has issue. Sorry to ramble on, but maybe something recognizable to you in here. Thanks again for trying to help me out. Chris
The dip switch settings are not proprietary. They are in the manuals and training manuals for the machine and anybody can find them. I have the books for this drive. I will look for the settings and get them to you but i am going out of town until Monday so it may be Monday night before i can get the settings to you. And just so you know. Dont let anyone touch the drives for repair. Order from your distributor or Okuma. Which is cheaper, an inexpensive repair or your machine down due to inproper repair. It is always a good idea to stay with the manufacturer especially with electronics. Trying to save money there will only cost you later.
Thanks cnczilla, appreciate the help and I will look for them monday then. I have most manuals for this machine but could not find info on switches. The choice to cut corners was not mine, and recommendations to follow up with local okuma rep have been pushed aside due to budget. Usually my bosses have no problem with calling factory in, so I'm thinking they feel there has been too much invested in this machine considering it's age.
recommendations to follow up with local okuma rep have been pushed aside due to budget
that's the case, when solution without Okuma representative is most expensive
SDU Alarm on a lb15 from 1987 sounds great, i had a ACT2SP3, with all time the same errors, was the board from the BDU50, i have change the complete drive for the servo, because BDU50 did not more exist. BL-D50 was the new drive, also i changed the power supply, all works well to now. Ask here for your switches
http://my.cfanet.com/~cncinc/servorepair.html
Okay, here is my concern-a burned up transformer. Not normal at all. Okumas are VERY sensitive to resistance internally to the transformer. They regen back through the line, and if you have too much impedance you will overheat the drive and cause decel alarms. Thats not to say there is not something wrong elswhere, like bad regen trans or whatever, but i've never had a transformer go up in smoke.
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