# OC message on the VFD display



## John Valdes (May 17, 2007)

It could be the drive. You can clear the fault? Does it run after you clear it? 
You said you disconnected the spindle motor? Did you take the wires loose from inside the drive itself? Or did you disconnect them at the motor?
You need to isolate the motor from the drive and see if the drive will run without a motor connected.
Does your drive support open loop operation? (operate without a motor)?

OC is a very common fault, and most always is indeed an OC condition. Sometimes it is very difficult to find the issue.
But eliminating the motor is where I would start. 
Make sure you are working in the right direction.


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## Jabberwoky (Sep 2, 2012)

Could we get a make, model, and ratings on the VFD? I may be able to tell you how to check the bridge for shorts if I can remember the layout of the buss. If there are buss terminals near the motor terminals in the VFD you can check from there. Power down, wait 5-10 min. Check to make sure the voltage from Buss+ to Buss- is near zero. Take an ohm meter and check from Buss+ to each motor terminal (R,S,T or T1,T2,T3 possibly)on the VFD and Buss- to each motor terminal on the VFD. If any of those read shorted (near 0 ohms) your VFD output bridge is toast. If its only a 10-15 hp VFD its probably not worthwile to repair, start looking for a replacement.


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## happytriger2000 (Jun 7, 2012)

Hello John,
Thank you for your reply.
That is what I'm trying to find out, Clear the fault, but how?

There's a connector between the cable from the Driver to the Motor, I unplugged it, power on the VFD, still "OC".

Does your drive support open loop operation? (operate without a motor)?

*2.1. Standard functions
• Reduced motor noise thanks to special PWM control technology.
• Output protected against short circuits between phases and to ground.
• Protection against over-current, over-voltage and under-voltage.
• Ability to withstand mains power outages of up to 15 ms.
• Sinusoidal output current from sinusoidal PWM.
• Smooth, controlled motor rotation even at very low speeds.
• Programmable slip compensation to minimise load-related speed variation.
• Manual or automatic low speed voltage boost.
• Automatic voltage and frequency control in case of overload to avoid motor stalling.
• Keypad or RS 485 serial line parameter control.
• Referencing with 0...10 V, -10...10 V, 0...20 mA, 4...20 mA analog signal, or via serial line.
• Programmable DC braking.
• Wide selection of V/f ratios.
• Overload level control.
• Non-volatile memory for the last 4 alarm event messages; messages not lost even if power is
switched off.
• Choice of open loop or closed loop functioning.
• RS 485 serial line control.
• IP 23 or IP 40 protection rating with special covers (supplied) fitted.
• 4 sets of linear or ‘S’ acceleration/deceleration ramps.
• 8 multi-speeds.
• Drive potentiometer with or without memory.
• Independent PID function.
• Critical frequency skipping.
• DCBUS control overvoltage prevention.
• Maximum output frequency 500Hz.
• PWM regulation up to 18 kHz.
• 150% overload for 60 secs. every 10 minutes.
• Integrated EMI filter (class A or B).
• 6 programmable digital inputs.
• 1 TTL/HTL encoder input that becomes +2 digital inputs.
• 2 NO/NC programmable relay outputs.
• 1 analog input for 0...10 V, 0...20 mA, 4...20 mA signals.
• 1 differential analog input for 0...10 V, 0...20 mA, 4...20 mA signals.
• 1 +/- 10V dc analog output.
• 2 programmable digital outputs.
• Integrated braking unit.*


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## JRaef (Mar 23, 2009)

I agree with John, you need to further isolate the location of the fault by separating the motor leads at the *drive* end if you have not already. If the problem goes away now, then it was in your wires to the motor which would be an easy thing to fix. If you already did separate them at the drive output terminals, then it is inside the drive and likely a shorted transistor.

I couldn't find anything on HSD selling drives though. They are well known for high speed spindle motors, but are typically used with a drive from someone else. But DPL didn't come up either, so no idea what you have there. Maybe HSD, like a lot of other motor mfrs, experimented with brand labeling drives for a while? If so you may be SOL as far as getting it repaired unless you can determine the real mfr.

PS: Crossed your response in the ether. Looks like it is in the drive then.


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## Jabberwoky (Sep 2, 2012)

happytriger2000 said:


> HSd DPL series, has anyone used this type of Inverter before and how do I get rid of the "OC" message?
> 
> 
> thanks,


Does anyone know if the HSd DPL is a new model Yaskawa? I don't recognize it.


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## JRaef (Mar 23, 2009)

Here's a clue (I love a good Google challenge). Not many drives go to 18kHz carrier frequency, most stop at 15kHz, so it looks like it might be either a Delta VFD-M series or a Control Techniques SK Commander series. If it's green or says it is made in the UK, it's the CT drive. If it says it is made in Taiwan, it is the Delta. My money would be on the Delta drive because they are cheap, and machine OEMs like cheap. Plus it appears you are in Taiwan, which might add to the likelihood if the machine was built there.


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## Jabberwoky (Sep 2, 2012)

JRaef said:


> Here's a clue (I love a good Google challenge). Not many drives go to 18kHz carrier frequency, most stop at 15kHz, so it looks like it might be either a Delta VFD-M series or a Control Techniques SK Commander series. If it's green or says it is made in the UK, it's the CT drive. If it says it is made in Taiwan, it is the Delta. My money would be on the Delta drive because they are cheap, and machine OEMs like cheap. Plus it appears you are in Taiwan, which might add to the likelihood if the machine was built there.


Oh man I should have seen that. I'll bet its a Delta also. For a cheap drive they aren't that bad. I have only installed a few so far though. I really don't know what the interior of those look like, I haven't rebuilt any of that make yet.


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## John Valdes (May 17, 2007)

happytriger2000 said:


> Hello John,
> Thank you for your reply.
> That is what I'm trying to find out, Clear the fault, but how?
> 
> ...


Choose open loop in the parameters and disconnect the wires that leave the VFD and go to the motor. Take them loose with a screwdriver from the VFD terminal strip. Also disconnect the feedback device if you have one. Or turn it off.
Power it back up and see if the Fault remains. Give it a speed reference/signal to be sure.
If the fault remains, it is inside the drive.


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## happytriger2000 (Jun 7, 2012)

Jabberwoky said:


> Could we get a make, model, and ratings on the VFD? I may be able to tell you how to check the bridge for shorts if I can remember the layout of the buss. If there are buss terminals near the motor terminals in the VFD you can check from there. Power down, wait 5-10 min. Check to make sure the voltage from Buss+ to Buss- is near zero. Take an ohm meter and check from Buss+ to each motor terminal (R,S,T or T1,T2,T3 possibly)on the VFD and Buss- to each motor terminal on the VFD. If any of those read shorted (near 0 ohms) your VFD output bridge is toast. If its only a 10-15 hp VFD its probably not worthwile to repair, start looking for a replacement.


@Jabberwoky,
I uploaded the DLP pdf file, please have a look.
Here is the spec of the Inverter:


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## JRaef (Mar 23, 2009)

Made in Italy? Huh, well that blows my theory, however they may have a loose interpretation of the term "made". I used to do business with an Italian VFD mfr called Elletronica Santerno and all of their stuff said it was "Made in Italy", but when I asked them about that, they said they didn't have any actual production facilities IN the country, it was all outsourced, but they _shipped_ everything from Italy. Their small drives looked EXACTLY like LG drives.


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## Jabberwoky (Sep 2, 2012)

Hmm Italian? The only Italian drives I have worked on were Amicon DC drives. I'm thinking this isn't the original drive tag though. HSD probably rebranded it. Can I get a photo of the display and touchpad? I can almost always figure out the make from that. If the drive itself doesn't have one I may just need an overall picture.

Oh did you try the steps I posted for checking the shorted outputs? Or even try John's open loop run? If you disconnect the motor leads some drives have a Feedback test or tune. That will ramp the drive in open loop mode. It is looking for the appropriate encoder or tach feedback by doing this which it won't find but it will tell you if the drive is the problem when it faults OC before the test is finished.


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## happytriger2000 (Jun 7, 2012)

Hello guys,
I have just tested the drive with out the Motor or load and still appearing OC. When reset or clear fault by pressing the arrow up and down buttons together, the display shows 0, but soon after it jump back to OC, I can hear the relay flick back and forth.Sometime it stays at O for more than 5 sec, sometime longer but it will eventually jump back to OC.


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## Jabberwoky (Sep 2, 2012)

I have some bad news If you tried to run it like you show in the photo and it gives the OC then it is a bad VFD. Start calling HSD for a replacement.

On another note. That may be the first time I have seen this make and model. HSD might have actually contracted somebody to build drives exclusively for them. I have never seen that keypad but the terminal layout looks familiar. I'll probably think of it sometime tonight at work.


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## happytriger2000 (Jun 7, 2012)

Contacted HSD and the manufc.: TDE Macno

Thank you all.


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## JRaef (Mar 23, 2009)

happytriger2000 said:


> Contacted HSD and the manufc.: TDE Macno
> 
> Thank you all.


Huh. Thought I had seen them all. Their larger drives look just like Danfoss, but not this series. This is a new one on me. They probably never make it here to the US because they do not appear to have a 480V version at all. 2kHz maximum output frequency though, that's impressive. I can see why HSD might want to brand label them (aside from nationaistic tendencies). 2000Hz is a good thing if you are in the high speed spindle business.

I'll bet it's expensive if it really is "made" in Italy.


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## happytriger2000 (Jun 7, 2012)

I opened another new DPL 110 Inverter just to make sure this is not faulty, and tested with my HSD ES919A (not the client's spindle), and everything went quite smoothly. We were guessing the 1st Inverter might have faulty parts, it did not last more than 2 days, it will be sent back to HSD for repair.


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