AMK az-40 Drive system

[flexoprinting]

Hello Gentleman

Currently servicing an AMK az-40 drive system without current reading display. I would like to get an accurate amp reading to each of the four motors it supplies.
Using a Fluke i1010 current clamp is useless, it's Bandwidth rating is 10 KHz. The readings I'm getting are totaly unbeleivable, doing some googling it looks like
I need a probe with > 15 MHz Bandwith to accuarately asses each output. The expence of one is more than I can justify. I will be using a Fluke 8845 w/Fluke view
software to log my readings, so my questions are.

Considering the signal type, Can I use a current shunt to measure voltage across and calulate current accurately that way?

If so, would I need to put same value shunts on the other two phases as well during the test?

Chuck

 

[flexoprinting]

The spec sheet for Fluke 8845 A states it will read AC voltages up to 300 KHz, I don't know what frequency the drive is putting out yet but may find out today. I remembered Gunner talking about his little box
he carries with a low pass filter and fortunately found that thread again. I'm finding this approach more complicated than I care for or my pea brain can comprehend and may just ask the company to spring for a probe, I have other meters that read drive voltage but I can't record with them.

Chuck

 

[itsmoked]

Drives need very accurate knowledge of the current to do their jobs well. Is there really no way to ask that drive what the current is?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[flexoprinting]

Hi Keith
This unit was purchased used, we don’t have install manual but I have parameter list. The drive is programed in German so I need to work with that as well…. Thank goodness for Google.

In parameter 00111, “Nennstrom” means “Rated current”. The manual I have, has English and German so this parameter is designated as “Nominal current” currently the machine is down so I don’t know if I will get running value. We are going to call AMK to see if they will supply an install manual, I will need to address the four individual drives if possible.

Easiest way for me would be to get a current probe which can see the signal accurately, going into drive parameters is going to need some read time.

Are most drive controllers capable to address each connected drive and do you think this will have that feature?

Thanks, Chuck

 

[flexoprinting]

With that said Keith, I would think this thing would shut down before catastrophic failure. When this thing goes down, it goes down hard. All three fuses in power supply
open. It also has lost one drive and one controller. The manufacturers of the equipment have no clue what is causing it. Finding someone qualified or available to fix this is proving to be a challenge.

One contractor came out and placed an over current sensing unit on the DC bus supply for the four drives down stream. This did not work, most likely because it did not
interpret the signal correctly. So then he move it to the AC supply to power supply unit. So it will of course shut down the whole works but the problem is still there somewhere within the system. I want to narrow it down and correct the actual cause. I performed all the mechanical checks I could think of but the components involved are many, narrowing it down to one drive system would be substantial.

Chuck

 

[itsmoked]

Ah, you're trying to troubleshoot a fault. That's different. You're right, you need a probe.

All the fuses going would also happen even on a minor overload. As soon as one fuse goes the other two would since their loading would jump up by the lost third. So, getting individual drive loading would be the route I'd take too.



Keith Cress
kcress -

http://www.flaminsystems.com

 

[John2025]

If the input fuses are blowing, but the dc bus current is not overcurrent then that sounds like a problem with the rectifier section. Lots of assumptions here: how long does it run before it blows. etc.

 

[flexoprinting]

Hi John


Happens out of the blue, very sporadic occurrences for no apparent reason. We had an analyzer/recorder on DC bus it did spike very high and of coarse fuses were history. This is why I need to check individually
each of the four drive outputs. When I find something that gives me a head scratching moment I will present it here.

My thoughts were possibly contactor relay in power supply was weak and dropping a leg to power supply, analyzer shows this did not happen. By the way cables and motors check out good with Megger.

Chuck

 

[waross]

Have you checked the input voltage? Is it possible that you may be getting voltage spikes on the supply?

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[flexoprinting]

Hi Bill

We have that base covered as well, installed incoming protection. No surges reported, additionally have phase loss protection also.
I'm not Drive qualified but learning fast these things can be very sensitive.

My concern now is the shut down protection that was installed may be Pandora's box. Normally when an E-stop for example is used the power is removed from motor and the circuitry inside the Drive bleeds off EMF through resister. This thing senses high current and opens the supply circuit to everything, therefore my thinking is the back EMF has nowhere to go except back into Drives because the circuitry that would normally bleed it off is disabled. Sorry if I sound naive but admittedly Drive technology is not my strong point. What do you think Bill?, is my theory plausible ?

Chuck