[contactirfu]

Wow! that's a jungle of wire out there!

[tenmetalman]

hello All,
I'm currently in the hospital so nothings happening with my mill project. my GP noticed that I was in atrial fibrillation during a routine followup. So in the following days I've had two Intracardiac Ultrasounds, a Cardiac Catheterization, several EKG's other procedures that I'm too lazy to look up the spelling on. I entered the hospital Friday afternoon & hope to go home late Monday after they do a something orther conversion to try and get my hearth back to it's normal beat.
I tried to put full 134vdc power to the X axis drive and had one strange short after another as soon as I applied the high voltage (in the proper sequense).I've started building a new drive using a new PCB to get beyong all of the scabs applied to the old board. I'm probably three hours from being done with the new board. I've removed the power dump for now. In one of the other posts I've noticed someone talking about a soft start. I'm thinking of giving that a try when next I power up the high voltage.

more as it occurres
Paul



gep thenerative













































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[kreutz]

Paul;

Forget about the drives for a while and get better.

Your friend,

Kreutz.

[tenmetalman]

Kreutz & Aill,
I'll probably work on the new drive card because this is one of the most peaceful, satisfying things I currently do. the long trip to get to this point makes actual progress feel good. Probably for the next couple of weeks I'll have
to walk around the house & down to the electronic workv area I use. I know we've talked around the subject of a soft start but my thinking is driven by the fact that starting a servo requires about 15 I'm not sure how high the current draw is when just appliying the 134vdc to a drive. I'll check the actual draw next.
Paul

[kreutz]

Kreutz & Aill,
I'll probably work on the new drive card because this is one of the most peaceful, satisfying things I currently do. the long trip to get to this point makes actual progress feel good. Probably for the next couple of weeks I'll have
to walk around the house & down to the electronic workv area I use. I know we've talked around the subject of a soft start but my thinking is driven by the fact that starting a servo requires about 15 I'm not sure how high the current draw is when just appliying the 134vdc to a drive. I'll check the actual draw next.
Paul

Hello Paul;

Take it easy and take the time to recover, you have been under a lot of stress.

Soft-start objective is to go easy on the power lines when you turn on your power supply (it saves fuses and having to reset breakers), it really does not help a lot the load. I recommend soft-start for loads over 2KVA in order to avoid the brownout (line voltage drop) associated with a high inrush current.

Your HP_UHU should be OK if the 15V and Motor voltages are turned ON and OFF with a delay, the 15 volts first at turn ON and last when turning off (less than 1 second delay is enough).

Best regards,

Kreutz.

[contactirfu]

Paul, get well soon - we still have a long way to go to get your mill in working order.

I will probably start making a wiring diagram of my setup so that it can help you do yours.

RGDS
IRfan

[H.O]

Hi Paul,

First of all I wish you a quick recovery, everything else is secondary right now!

I'm running my system on 130VDC and so far it seems to work fine. I'm still running "on the bench" though (unloaded motors). I DO however use a softstart, two actually, one on the primary side of the 4kVA 3-phase transformer to save the fuses and one on the DC-side to lessen the load on rectifier as the capacitorbank loads.

I have seen NO problems when it comes to the powerstage of the HP-UHU (except when I shorted the output of course) so perhaps adding a softstart will do your system some good.


As a test, take a relay big enough to handle the current and wirewound resistor, say 100ohm 10-25W. Wire the resistor in series with the positive lead going from the rectifier to the capacitorbank. Then wire the relay so its contacts bypasses the resistor when then relay activates.

Now take 24V (or whatever the coil voltage on the relay is), run i thru a toggle switch to the coil of the relay. Power up the system with relay in the "off-state", the current charging the capacitorbank now passes thru the resistor making the voltage rise MUCH slower than before, after a couple of seconds flick the switch to bypass the resistor. If this seems to work you can replace the switch with a timing relay or a simple voltage divider from the 130VDC.

/Henrik.

[contactirfu]

Henrik, I think Paul already has that setup with him!

I still don't know why he is having burnout issues

Paul u get well soon and if you can get a internet connection over to the shop with you webcam there we can fix things there over skype.

RGDS
IRfan

[kreutz]

Soft-Start

I don't like the idea of using relay contacts on the DC side of the power supply, they (when used with the power resistor Henrik talks about) limit the initial charge current of the DC capacitors but have the nasty tendency to erode and create more problems after a while.

The soft-start on the AC side (primary of the motor's power supply transformer) will solve two problems at the same time: initial capacitor charge current + transformer magnetizing current, so it is the method most employed in the industry.

I will post schematics of a simple soft-start circuit soon. About the 24 Volts, it is a standard in the industry, so 24V dc or AC High current rated contactors are easier to find and cheaper than the 12 volt counterpart, also the 24 V power supplies are easier to find in the industry.

I am working on a B.O.B. that will include the soft-start, regenerative energy dumping, and power supply sequencing (it is not ready yet), will also include an optional isolated 0-10V spindle speed control, charge pump, two 30 Amps SPST relays + limit/home switches isolated inputs and EMG-Stop interface.

Take your time to recover, getting well is the first priority.

Best regards,

Kreutz.

[tenmetalman]

Good Morning All,
thanks to everyone for your replys, as Irfan states I am using a timer & relay to delay the charging of the 134vdc power supply. Before that I had been using a toggle switch to activate the relay that turns the high power supply on when I was ready for it.
I'm one of those people who thought I had the problems sorted out after successfully bringing my mill system up & having the 134vdc power on for hours at a time. then as another list member says "Boom" and one at a time I damaged the power section of my three drives while attempting to sort out the new problem. I've damaged & repaired the drive that I refer to as my "X" axis that just before coming to hospital I started constructing a new "X" drive on a new PCB to eliminate problems the drive may have been bringing to the party. I'm using a massive relay that controls the 90vac going to the 134vdc power supply.
Time will go back to being extremely limited as far as working on the "project" when I'm out of here. I'll need to create some paying projects to recoup the out of hand expenditures as the insurance company's like to call it. I'll need to be extremely careful of where I'm spending my time as "My mill project" is a very touchy subject with the wife. It has brought us to the brink of divorce several times in the last couple of years. unfortunately she doesn't get the pleasure this whole project, lists, groups, & individuals has & continues to give me. In spite of myself & everything else I just won't/can't let go of this.
anyway, I find myself thinking that this time will actually be good for project. It'll give me/us the time we need to figure out how to proceed.......
thanks again everyone
Paul
BTW I also will work on creating a current schematics that means something to others as well as myself.

[contactirfu]

I'm using a massive relay that controls the 90vac going to the 134vdc power supply.
Paul
BTW I also will work on creating a current schematics that means something to others as well as myself.

Paul - putting a relay on the secondary as you have done is wrong - according to Kreutz, this should be on the Primary side - not on the secondary is what Kreutz says.

I myself have a very crude set up and planning on making a new good looking and better performing control box - like the one I am using for my bigger machine (mechmate)

If kreutz gets his interface boards in a month then I will be soon testing em out - a

also I am planning to purchase a 2.2kw electro spindle from a chinese source and will be using a delta VFD to control the same and if Kreutz has the spindle control box then I can test that too - is your spindle VFD controlled paul?

ok u have to get well now - I am just filling up your thread with my ranting

sorry

RGDS
Irfan

[H.O]

FYI, what I meant wasn't to switch the DC with the relay, as in putting it in between the capacitors and the drives. I meant putting the relay across a resistor between the rectifier and the capacitor(s). This will limit the inrush current to the caps thus limit the DC voltage rise time and lower the "impact" on the rectifier.

Obviously the relay will have to withstand normal operating current + some. In my case I'm using Telemecanique LC1D32 contactors, these are rated 32A per contact. On the DC side I'm using all three contacts in parallel.

Of course, a soft start on the primary also helps and may be enough i most cases. (I have that too...)

During the last 6 months of testing and hunting encoder problems etc I've run with a variable transfomrer feeding the ordinary tranformer. So I've been manually ramping the voltage up every time I power up the system. I've seen a lot of different problems during this time but not once seen or heard a "bang" due to a blown powerstage. (Hope I didn't jinx it now....)

/Henrik.

[contactirfu]

HI Kreutz, along with the SPST relays option should also be available to switch a few SSR's instead of the relays - probably a jumper to either use the relay or the SSR.

Its good to know that we can use this now - I am assuming this will be SMD based?

will this also handle the Estop sequencing - mean if a drive faults then everything is put off?

RGDS
Irfan

[kreutz]

HI Kreutz, along with the SPST relays option should also be available to switch a few SSR's instead of the relays - probably a jumper to either use the relay or the SSR.

Its good to know that we can use this now - I am assuming this will be SMD based?

will this also handle the Estop sequencing - mean if a drive faults then everything is put off?

RGDS
Irfan

The optional Expansion board Rev2.1SMD will take care of the SSR interface, and the 0-10 volts module could be optionally added. It will be a few dollars cheaper than the version with the relays on board. Both will be SMD based. The DIY version will be modified (in version 2.1TH) to add the 0-10V module connector and provision for VCC_PC output to the screw terminals, in order to drive SSRs too. I will post new schematics soon..

The 30 Amps Relays are a lot cheaper than the SSRs (which will not be included).

Best regards,

Kreutz.

[contactirfu]

ok Kreutz, I want to buy one of your BOB with spindle control when are u planning to get it to us, with all that you discussed above.

RGDS
Irfan

[kreutz]

ok Kreutz, I want to buy one of your BOB with spindle control when are u planning to get it to us, with all that you discussed above.

RGDS
Irfan

I am still on the design/prototyping stage, will send the gerbers to the fab early January. Will keep you posted.

Thank you,

Kreutz.

[kreutz]

duplicated....

[tenmetalman]

Hey All.
it's beginning to look like I'll be restricted from very much shop time when I leave the hospital to go home. this should mean I can spend reasonable amounts of time at my electronic assembly area............... If this pans out I think I'll build at least two new drives that haven't been repaired/aultered etc.
I keep thinking of soft starts, where & what to apply to test the theory in my application......... quite awhile back I purchased some thermistors, at least two sizes knowing me. I'd like to try thermistors to slow the on rush on start up. where & what size, grade, ? becomes the question. I'm currently unable to check what I have so I guess we'll have to look at this on a theoretical level. I'm guessing that I would put one thermistor in each leg of the incoming voltage to the 134vdc power supply. I'm posing this as a question to you whom know more about this ?
with luck I'm going home tonight & could list the actual thermistors I have to see if they'd work...............
Thanks
Paul

[kreutz]

........I keep thinking of soft starts, where & what to apply to test the theory in my application......... quite awhile back I purchased some thermistors, at least two sizes knowing me. I'd like to try thermistors to slow the on rush on start up. where & what size, grade, ? becomes the question. I'm currently unable to check what I have so I guess we'll have to look at this on a theoretical level. I'm guessing that I would put one thermistor in each leg of the incoming voltage to the 134vdc power supply. I'm posing this as a question to you whom know more about this ?
with luck I'm going home tonight & could list the actual thermistors I have to see if they'd work...............
Thanks
Paul

NTC resistors (resistors with negative temperature coefficient) are successfully employed as soft start (and charging current controllers) for small power supplies, they work "hot" (the hotter they get the less resistance), but they are not a solution at the power level of the HP_UHU drives.

Get Well and best regards,

Kreutz.

[tenmetalman]

NTC resistors (resistors with negative temperature coefficient) are successfully employed as soft start (and charging current controllers) for small power supplies, they work "hot" (the hotter they get the less resistance), but they are not a solution at the power level of the HP_UHU drives.

Get Well and best regards,

Kreutz.

Well fart ! ! ! !
What's next ? I have a stash of Large oil Electrolyte & start capacitors, some transformers, wire wound resistors & so on that came out of a backup power supply. (Don't ask I couldn't get the batteries..) I know Kreutz is real busy trying to make ends meet. I'm in the market for suggestions that don't involve additions relays............
Paul