SPZ Meaning? Mill spindle problem

jvobike · Mar 18, 2018

Hello,

I have a Shizuoka Millmaster B-3V CNC mill and recently I had a power surge in my building. Since this happened, I have had an alarm LED light up in my spindle amplifier control board region of my machine. I have been having very hard luck trying to find help or an owner's manual for this machine as it is over 30 years old. I have contacted Shizuoka Tekko Japan with no solution.

The LED is labeled LD20 and SPZ. I ask what the SPZ denotation might mean. I am assuming it stands for Spindle "Z" but what should this mean to me as for how to fix it? In it's current state, if I turn on the spindle, the spindle will not go and I will have fuse blown in my machine.

Any help would be appreciated, I have plenty of pictures on this problem if they may help.
Thanks

Roooster · Mar 18, 2018

This board?
SHIZUOKA B-5V CNC VERTICAL MILL CIRCUIT BOARD PRS-93 B AW-35-82 PRS-93B | eBay

Vancbiker · Mar 18, 2018

IIRC that machine uses a Fuji Electric DC spindle drive. I no longer have information on those and it has been many many years since I last worked on one.

Since you had a voltage spike and are now blowing fuses, that sounds like a shorted thyristor or SCR.

Post up the manufacturer and model of spindle drive. Then we may be able to figure more out.

jvobike · Mar 18, 2018

Roooster,
That looks identical to my board, yes. I am not sure myself if replacing the board will fix the problem however. Firstly, I am still not sure what the light means. Can you input if replacing the board should alleviate anything? I have attached picture of my board

Vancbiker,
I have found only 1 item that says Fuji on it in my spindle drive cabinet, see attached. I have found a Sanyo Denki SP-4146B name plate that I believe is the make and mode of the spindle drive. I have attached pictures of the Fuji and Sanyo Denki items. Can you elaborate on what a shorted thyristor or SCR may be?

Thank you

jvobike · Mar 23, 2018

Bump, I can use any and all input here. I am a newer machinist and without my Mill I am like a doctor without a stethoscope at my store here
Thanks

Vancbiker · Mar 23, 2018

jvobike said:
.....I have found only 1 item that says Fuji on it in my spindle drive cabinet, see attached. I have found a Sanyo Denki SP-4146B name plate that I believe is the make and mode of the spindle drive. I have attached pictures of the Fuji and Sanyo Denki items. Can you elaborate on what a shorted thyristor or SCR may be?

This is likely to be a tough one for someone without electrical/eletronics experience...

So the drive is Sanyo Denki. I don't have any service manuals for that brand. You mioght spend some time on google looking for documentation of that old unit. While you are at it you might search for firms that repair DC motor controllers. Your best bet will likely be to remove the unit from the machine and send it to a repair center.

Typically, DC spindle drives use a set of electronic devices to convert AC line power to DC of varying voltages to run the spindle motor at various speeds. Those devices are usually thyristors or SCRs. When one gets a short, it passes too much current to the DC side of the drive or another AC leg. Typically they are fused so the excess current blows a fuse preventing further damage.

jvobike · Mar 23, 2018

Vancbiker,

Thank you for the help. From talking to a tech at Shizuoka Tekko, Japan, i was able to get this wiring diagram from a "similar Sanyo Denki" spindle drive - I wasn't able to upload here due to file size so click link below to download wiring diagram:
Uploadfiles.io - img-31516197.pdf

This is what the Shizuoka Tech emailed me along with this wiring diagram:
"I tried looking, but I could not find that model.
Since there was a circuit diagram close to it, I attached it"

Could you point out which symbols are the thyristors or SCRs and/or any tips for looking at thyristors/SCRs on the actual, physical board.
Thank you very much for the inputs

Vancbiker · Mar 23, 2018

jvobike said:
.....Could you point out which symbols are the thyristors or SCRs and/or any tips for looking at thyristors/SCRs on the actual, physical board.
Thank you very much for the inputs

The schematic you linked appears to be just a portion of your board. I could not find the LED SPZ on that schematic. The thyristors or SCRs will be behind this board and connected to the board by wiring coming from the connector marked CN21 on the right edge of the schematic. Based on the notation Th1 through Th12, I'm thinking that your drive will be a thyristor type.

jvobike · Mar 25, 2018

Vancbiker,

Thank you for your input. I will poke around in that area with an Ohm meter to find a shorted thyristor or SCR. any tips for replacing a shorted Thy/SCR should one be found?

Thank you

jvobike · Mar 28, 2018

Hello,

I have opened my control board and find the bank of Thyristors as seen in attached pictures. Upon measuing voltage across the top and bottom 3 horizontal array of Thyristors, there appears to be a voltage; however, there is no voltage reading among the middle six (vertical orientated) arrays of Thyristors. Should a simple replacement of the Thyristors fix the issue or is the issue deeper you think? Please advise

Thank you
Nic

Vancbiker · Mar 28, 2018

Without having a diagram, I could not say for sure. I do not think that it would though. You might google for images of Thyristor or SCR diagrams and see if something you find appears similar to your drive. Then you would have a better idea of how to proceed.

I still think sending the unit to a repair company would be your best action.

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