DYN2 drive issues

I recently make the jump from steppers to servos on my taig mini mill. I run linuxcnc through mesa 5i25 & 7i76 cards. I had the system up and running for a total of 10 hours before I started running into issues. Now I tend to blow a DYN2 drive after a couple minutes of operation. DMM first suggested that I add additional capacitors to my system after the PSU so I did. I tested this and broke yet another DYN2 drive. Anyway, here is the schematic for the power side of my system:

https://i.imgur.com/ldYlzBB.jpg?1

I have 120 coming from the wall (through a power strip) into a 60V DC PSU. The 3 fuses that are shown are 15A slow blow fuses (digikey pn: F1776-ND). Both times I have fried a DYN2 drive, the fuse on the X axis has blown. The first time a drive was fried, it was when my mill was decelerating in the X from 300 IPM to 0. I was manually jogging (with the keyboard) the second time so it is difficult to know exactly when it happened. I do not have any of the alarm pins on the DYN2 hooked up at the moment.

System setup
Max velocity: 5 IPS (300 IPM)
Max acceleration: 20 inches per second per second
Ball Screw Pitch: 2.5mm (for maths sake, lets call it 0.1")
DYN2 drive PN: DYN2-TLAS-00
Motor PN: 57N-DHT-6ATD1

I sent the first fried DYN2 back to DMM and this was their response:

The drive you returned had two burned power transistors caused by over voltage, so we will need to invoice for the drive repair and will send a payment link now. Make sure to put the capacitors at the 60VDC power supply output to smooth and voltage fluctuations.

I added the two capacitors as they suggested and fried a second drive. At this point, I believe they are just taking guesses and hoping the problem goes away. But at $150 and 1 week lead time, I do not want to keep taking guesses. I personally don't understand how a single drive can be failing due to over voltage from the PSU since all 3 drives are connected in parallel. Does anyone here have any ideas on what I can/should test? The last kit I purchased from them (due to arrive tomorrow) includes two 48V PSUs (to get the necessary power), a new motor and a new DYN2 drive. I will have a total of 4 working drives once this package arrives (X,Y,Z & spare).

Thanks,
Travis

Quote:

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Originally Posted by Travis1581

I recently make the jump from steppers to servos on my taig mini mill. I run linuxcnc through mesa 5i25 & 7i76 cards. I had the system up and running for a total of 10 hours before I started running into issues. Now I tend to blow a DYN2 drive after a couple minutes of operation. DMM first suggested that I add additional capacitors to my system after the PSU so I did. I tested this and broke yet another DYN2 drive. Anyway, here is the schematic for the power side of my system:

https://i.imgur.com/ldYlzBB.jpg?1

I have 120 coming from the wall (through a power strip) into a 60V DC PSU. The 3 fuses that are shown are 15A slow blow fuses (digikey pn: F1776-ND). Both times I have fried a DYN2 drive, the fuse on the X axis has blown. The first time a drive was fried, it was when my mill was decelerating in the X from 300 IPM to 0. I was manually jogging (with the keyboard) the second time so it is difficult to know exactly when it happened. I do not have any of the alarm pins on the DYN2 hooked up at the moment.

System setup
Max velocity: 5 IPS (300 IPM)
Max acceleration: 20 inches per second per second
Ball Screw Pitch: 2.5mm (for maths sake, lets call it 0.1")
DYN2 drive PN: DYN2-TLAS-00
Motor PN: 57N-DHT-6ATD1

I sent the first fried DYN2 back to DMM and this was their response:

The drive you returned had two burned power transistors caused by over voltage, so we will need to invoice for the drive repair and will send a payment link now. Make sure to put the capacitors at the 60VDC power supply output to smooth and voltage fluctuations.

I added the two capacitors as they suggested and fried a second drive. At this point, I believe they are just taking guesses and hoping the problem goes away. But at $150 and 1 week lead time, I do not want to keep taking guesses. I personally don't understand how a single drive can be failing due to over voltage from the PSU since all 3 drives are connected in parallel. Does anyone here have any ideas on what I can/should test? The last kit I purchased from them (due to arrive tomorrow) includes two 48V PSUs (to get the necessary power), a new motor and a new DYN2 drive. I will have a total of 4 working drives once this package arrives (X,Y,Z & spare).

Thanks,
Travis

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I see you have a major problem you can not have the fuse's where you have them if the fuse blows which it will being only 15A the drive will be smoked I use 70V DC supply on the new Dyn2 drives

What is the power supply you have I would start at this point and the fuse's have to go from where they are you can only have one before the caps and must be at least 20A

The caps may be to low as well there Breakout Board has 2200uf and the original had 4700uf

Quote:

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Originally Posted by mactec54

I see you have a major problem you can not have the fuse's where you have them if the fuse blows which it will being only 15A the drive will be smoked I use 70V DC supply on the new Dyn2 drives

What is the power supply you have I would start at this point and the fuse's have to go from where they are you can only have one before the caps and must be at least 20A

The caps may be to low as well there Breakout Board has 2200uf and the original had 4700uf

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So if I understand correctly, what you are suggesting is this with the fuse being 20 amps:

https://i.imgur.com/Qutif87.jpg?1

Please forgive me, but I don't understand how this changes anything. I will gladly make the switch, but I want to understand why this should fix my problem. Why is it a problem having the fuses where they are?

I am using a 60V switching PSU. This one:

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

I also have added additional capacitors (Per DMMs recommendation) and am currently at 3200uF.

Travis;
In your original fused configuration, if you drop a leg (blow a fuse) it may cause some kind of surge. I have always been warned against fusing single line input to the amps. Give it a try and hope it helps.
On another subject, I'm trying to install Linuxcnc on my old router with dyn2 drives and 750 watt motors. Would it be possible to get a copy of your ini and hal file? I'm trying to learn this op system so anything I can get my hands on is appreciated.
Good luck.
Bill

Quote:

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Originally Posted by Travis1581

So if I understand correctly, what you are suggesting is this with the fuse being 20 amps:

https://i.imgur.com/Qutif87.jpg?1

Please forgive me, but I don't understand how this changes anything. I will gladly make the switch, but I want to understand why this should fix my problem. Why is it a problem having the fuses where they are?

I am using a 60V switching PSU. This one:

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

I also have added additional capacitors (Per DMMs recommendation) and am currently at 3200uF.

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Yes that is the best way to do your wiring and the fuse will have to be a minimum of 20A that power supply will also have a fuse inside on the input power so no other protection need for the power supply

Twist the wire pairs as well this will help with EMI

The caps should be ok the problem with the fuse's where you had them once they blow there is nowhere for the Back EMF to go and this would overload the drives in deceleration, if it still gets to high you may need a braking resistor but not sure if they can be fitted to the Dyna2 drives, but have never seen the need to have them either, so this should fix your problem with this change, attached photo of packages I used to do you will see the Twisted wiring

Quote:

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Originally Posted by mactec54

Yes that is the best way to do your wiring and the fuse will have to be a minimum of 20A that power supply will also have a fuse inside on the input power so no other protection need for the power supply

Twist the wire pairs as well this will help with EMI

The caps should be ok the problem with the fuse's where you had them once they blow there is nowhere for the Back EMF to go and this would overload the drives in deceleration, if it still gets to high you may need a braking resistor but not sure if they can be fitted to the Dyna2 drives, but have never seen the need to have them either, so this should fix your problem with this change, attached photo of packages I used to do you will see the Twisted wiring

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I just ordered some 20 amp fuses and will try this once they arrive (the 11th). Just out of curiosity, what wires are you twisting, power or signal? That setup is a lot cleaner than what I am working with...

- - - Updated - - -

Quote:

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Originally Posted by bill south

Travis;
In your original fused configuration, if you drop a leg (blow a fuse) it may cause some kind of surge. I have always been warned against fusing single line input to the amps. Give it a try and hope it helps.
On another subject, I'm trying to install Linuxcnc on my old router with dyn2 drives and 750 watt motors. Would it be possible to get a copy of your ini and hal file? I'm trying to learn this op system so anything I can get my hands on is appreciated.
Good luck.
Bill

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PM sent with info requested

I ran a loop of 100 of the following code:
G0 X7
G0 X0

No issues running full speed! I did slow down the acceleration slightly, but I think I will bump it back up and try again.

It's the rapid decel that is causing the damage. If the recovered power is greater than the losses in the system and the servo driver, the difference will end up being dumped in those capacitors ie as a voltage surge. You can't store much energy in a couple of small caps like those, so you need to either limit the max decel or fit some form of voltage clamp. Think about it, all that inertia (kinetic energy) in the work, vise, table, saddle etc moving at speed has to go somewhere, ideally as heat where it won't cause a problem.

On my larger machine, I have a braking module that clamps the voltage somewhere between normal voltage and the max allowable voltage for the servo drives. If you don't have one of those, you simply need to limit your max decel rates. If you don't know what is happening with the voltage (have you got a volt meter or scope?), you will only know you've overdone the decels when you pop yet another drive. I think you know of some settings that don't work now - 20 ins per sec per sec from 300 IPM.

Quote:

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Originally Posted by Travis1581

I ran a loop of 100 of the following code:
G0 X7
G0 X0

No issues running full speed! I did slow down the acceleration slightly, but I think I will bump it back up and try again.

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You should be good now if you rewired everything as it should be, you can max out your acceleration until the drive faults then lower it just enough and a safety factor so that it can't fault out from over acceleration

Twisting all wires helps don't twist in any Ground wires though just power pairs and signal wires

Quote:

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Originally Posted by Muzzer

It's the rapid decel that is causing the damage. If the recovered power is greater than the losses in the system and the servo driver, the difference will end up being dumped in those capacitors ie as a voltage surge. You can't store much energy in a couple of small caps like those, so you need to either limit the max decel or fit some form of voltage clamp. Think about it, all that inertia (kinetic energy) in the work, vise, table, saddle etc moving at speed has to go somewhere, ideally as heat where it won't cause a problem.

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Some good thoughts but not needed in this case

Quote:

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Originally Posted by Muzzer

On my larger machine, I have a braking module that clamps the voltage somewhere between normal voltage and the max allowable voltage for the servo drives. If you don't have one of those, you simply need to limit your max decel rates. If you don't know what is happening with the voltage (have you got a volt meter or scope?), you will only know you've overdone the decels when you pop yet another drive. I think you know of some settings that don't work now - 20 ins per sec per sec from 300 IPM.

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A Braking Resistor was not going to help his problem, and not needed, for a normal X Y Z axis machine, he will not pop another drive now that he has it wired correct

He can max out his acceleration until he gets a drive fault then back it off from that acceleration number

Quote:

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Originally Posted by Travis1581

I just ordered some 20 amp fuses and will try this once they arrive (the 11th). Just out of curiosity, what wires are you twisting, power or signal? That setup is a lot cleaner than what I am working with.

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When you said 20 Amp Fuses, I hope that you are not using them in place of the 15A how you had it wired before, if so the same thing could happen, only ( 1 ) fuse and placed before the caps is the only place you can have a fuse in this design

For wire being Twisted all except Ground

Quote:

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Originally Posted by mactec54

When you said 20 Amp Fuses, I hope that you are not using them in place of the 15A how you had it wired before, if so the same thing could happen, only ( 1 ) fuse and placed before the caps is the only place you can have a fuse in this design

For wire being Twisted all except Ground

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Yes, I now only have 1 20A fuse installed on the + side between the caps and the PSU.

I moved the Fuse as mentioned in the previous message. However, after a couple hours of actual operation, I now have a similar issue. I was in the rapid portion of a face mill operation moving at max speed from left to right on the X axis. The X axis just became unresponsive. I dug the USB cable out and plugged it in and "Lost Phase" appeared in the status area. This was a breath of fresh air since usually a power cycle clears the alarm and I just have to rehome before im back to cutting. However, it appears the lost phase is stuck. Here are a few things I have tried:

• X DYN2 drive w/o a motor or encoder - Lost Phase on X Drive
• X DYN2 drive w/o encoder, but motor plugged in- Lost Phase on X Drive
• X DYN2 drive with Y motor and encoder - Lost Phase on X Drive
• Y DYN2 drive with X motor and encoder - Lost Phase on Y Drive

The interesting thing is once I disconnected the X motor and encoder from the Y drive, the drive functioned again. It appears the problem follows both the X motor and the X drive.

Machine specifications:
Max Velocity: 5 IPS = 300 IPM
Max Acceleration: 20 (IPS/S)
X Travel: ~11"
60V 1200W PSU
3x 400W DMM Motors (57N-DHT I believe)
Mesa 5i25 & 7i76

I have a spare drive and motor I could swap out. But I really hate that I am burning $100+ every time I run this machine. Please be gentle, but here are some photos of my "enclosure."
https://www.cnczone.com/forums/attac...d=450294&stc=1
https://www.cnczone.com/forums/attac...d=450292&stc=1

Other than the obvious, "its a mess," does anything stick out as being obviously wrong? I am getting some help from some electrical techs at work, but any input would be greatly appreciated.

What kind of rating are these fuses ? My system is after many years getting assembled and I would imagine 20 amps is 20 amps ac or dc but for a 48volt power supply calling for 20 amp fuse what fuse should i get?