[gus]

I am sure guys here are running these on phase converters, too many crazy dc drive questions for there not to be. look through old posts, contact others who may not monitor this list all the time.


I wonder if continuing to move the phases around might be worth while, plot a logic table and try all possible combinations.


Also, if you can get your hands on a big isolation transformer, even to borrow, something with a lot of metal in it to put between the phase converter and the machine, maybe would dampen the spike.

Again, this is fundamentally a drive flaw, just because it works in all other aspects does not mean it is right. I had an older VFD that required and expensive external braking resistor, and without it would do as you describe. The lesson is that missing ocnnection that is otherwise unimportant will give you this error

[moonman5]

I am sure guys here are running these on phase converters, too many crazy dc drive questions for there not to be. look through old posts, contact others who may not monitor this list all the time.


I wonder if continuing to move the phases around might be worth while, plot a logic table and try all possible combinations.


Also, if you can get your hands on a big isolation transformer, even to borrow, something with a lot of metal in it to put between the phase converter and the machine, maybe would dampen the spike.

Again, this is fundamentally a drive flaw, just because it works in all other aspects does not mean it is right. I had an older VFD that required and expensive external braking resistor, and without it would do as you describe. The lesson is that missing ocnnection that is otherwise unimportant will give you this error

Hi Gus,

Huh! you have hit on two things I have been thinking about! firstly the easiest... "move the phases around " something I have not tried hard enough with,. As other post have said, the drive may be phase sensative, so I will def give that a try,

Secondly your idea on a "big isolation transformer" was something else swimming around in my head, if I could prove this works I would have no hesitation buying one, maybe I can pick one up from e-bay or somewhere.

I have searched the forums here over and over, and cannot seem to pinpoint an answer to my problem,

Thanks for your input Gus, appreciated,

Allen.

[tc429]

does your DC motor have a wound field? doubt its permanent magnet...if its wound field, is there a stabilizing shunt winding in the motor- saw one of those reverse wired before that caused all sorts of issues.
at 500 rpm on the spindle, is your motor going above base speed? if so there might be some field regulator issues. we had some antique ge valutrols on 850/2600 motors with 120 volt fields, in certain faults at max rpm(@ 2600 field was only around 12 volts) the fault would cause field current to return to full power immediately- well, 10x over field=10x over armature till it slows...2~3000 volts across the com would do heavy damage to the drives and the commutator- but this was big stuff...on a smaller drive, MOVs are about all they use to filter out spikes, but overvoltage from fast field rise at over base speed will cause high armature voltage bigtime.

quick comments on how non PM DC motors work, for those that never used these 'old' things-
max torque is continuous up to base speed, horsepower is constant from base to max rpm.
field voltage at or below base speed is full, armature voltage ramps up to increase rpm...at base speed or above, armature remains at full voltage, but field decreases to increase rpm. (complete field current loss if unchecked results in motor runaway- rpm is unlimited until the rotor grenades).
some larger motors had a stabilizing field winding(very heavy gage field winding) that is in series with armature solely to prevent runaway- they still use the small gage field wires for the bulk of below base speed field supply. if the stabilizing field is reverse wired, load decreases field, motor has crazy stability issues...

most dc motors have a direct coupled tach. *IF* your tach coupling is damaged, it *might* slip more in one direction than the other, *might* cause tach to overrun during fast braking, causing drive to think it needs to brake harder, repeat, pop. we had some old reliance REO-20 tachs with a 'rubber bladed' coupler that did this often...we chanced to a low backlash 'real' metal coupling to prevent it from recurring... careful with those dc wires too- a coworker at another plant lost some ribs, a lung, nearly his arm from reverse wiring a lathe drive tach- it ran away and the chuck exploded before the motor, runaway DC is scary stuff...on a mill its not as likely to explode as on a large lathe, but still, dont let the main switch be far out of reach when messing with non permanent magnet DC motors. opening the switch under load often blows the drive if its in regen, but better than grenading something.
most newer drives(after the late 80's) are pretty good at sensing tach divergence/runaway, but old stuff was scary.

some older dc drives used a NC contact across the armature leads for 'fixed' dynamic braking, the NC contact just put a huge wirewound resistor across the armature whenever the contactor opened...havent seen any like this in a long time, but might look for burnt contacts in the contactor...when stopping from under 500, does the contactor 'click' off before the spindle stops? if so it might have this hard DB hookup, and the resistor might be opening with higher heating, causing a dc spike...doubt it, just tossing ideas out there.

stupid thing that might work out if you cant drop the gain in the controller- a R-C network on the 0-10 volt line might be able to 'ramp down' the reference, and a parallel reverse diode to prevent most of the delay on accel...the .6 drop of the reverse diode will cause a slow response at the end of the accel, but might be a workaround...i'm assuming this machine is like in a home workshop, peak response not a huge concern? seems odd they have a accel pot but not decel if its a regen drive...if db there should be a huge discharge resistor...hmm... good luck

[moonman5]

does your DC motor have a wound field? doubt its permanent magnet...if its wound field, is there a stabilizing shunt winding in the motor- saw one of those reverse wired before that caused all sorts of issues.
at 500 rpm on the spindle, is your motor going above base speed? if so there might be some field regulator issues. we had some antique ge valutrols on 850/2600 motors with 120 volt fields, in certain faults at max rpm(@ 2600 field was only around 12 volts) the fault would cause field current to return to full power immediately- well, 10x over field=10x over armature till it slows...2~3000 volts across the com would do heavy damage to the drives and the commutator- but this was big stuff...on a smaller drive, MOVs are about all they use to filter out spikes, but overvoltage from fast field rise at over base speed will cause high armature voltage bigtime.

quick comments on how non PM DC motors work, for those that never used these 'old' things-
max torque is continuous up to base speed, horsepower is constant from base to max rpm.
field voltage at or below base speed is full, armature voltage ramps up to increase rpm...at base speed or above, armature remains at full voltage, but field decreases to increase rpm. (complete field current loss if unchecked results in motor runaway- rpm is unlimited until the rotor grenades).
some larger motors had a stabilizing field winding(very heavy gage field winding) that is in series with armature solely to prevent runaway- they still use the small gage field wires for the bulk of below base speed field supply. if the stabilizing field is reverse wired, load decreases field, motor has crazy stability issues...

most dc motors have a direct coupled tach. *IF* your tach coupling is damaged, it *might* slip more in one direction than the other, *might* cause tach to overrun during fast braking, causing drive to think it needs to brake harder, repeat, pop. we had some old reliance REO-20 tachs with a 'rubber bladed' coupler that did this often...we chanced to a low backlash 'real' metal coupling to prevent it from recurring... careful with those dc wires too- a coworker at another plant lost some ribs, a lung, nearly his arm from reverse wiring a lathe drive tach- it ran away and the chuck exploded before the motor, runaway DC is scary stuff...on a mill its not as likely to explode as on a large lathe, but still, dont let the main switch be far out of reach when messing with non permanent magnet DC motors. opening the switch under load often blows the drive if its in regen, but better than grenading something.
most newer drives(after the late 80's) are pretty good at sensing tach divergence/runaway, but old stuff was scary.

some older dc drives used a NC contact across the armature leads for 'fixed' dynamic braking, the NC contact just put a huge wirewound resistor across the armature whenever the contactor opened...havent seen any like this in a long time, but might look for burnt contacts in the contactor...when stopping from under 500, does the contactor 'click' off before the spindle stops? if so it might have this hard DB hookup, and the resistor might be opening with higher heating, causing a dc spike...doubt it, just tossing ideas out there.

stupid thing that might work out if you cant drop the gain in the controller- a R-C network on the 0-10 volt line might be able to 'ramp down' the reference, and a parallel reverse diode to prevent most of the delay on accel...the .6 drop of the reverse diode will cause a slow response at the end of the accel, but might be a workaround...i'm assuming this machine is like in a home workshop, peak response not a huge concern? seems odd they have a accel pot but not decel if its a regen drive...if db there should be a huge discharge resistor...hmm... good luck

Hi tc429,

Wow! fantastic reading! some really good stuff in your post, and some pretty scary stuff to, I have heard about spindles running of on there own....but exploding, that's a bit frightening! I think i'm gonna move the isolater just that bit nearer.

I ran some more tests today. If I ran the spindle at 2500 rpm in manual, I then changed the spindle speed in drops of 100...2400/2300/2200 rpm the machine handled it ok, Then I Ran the spindle at 3500 rpm and tried the same thing dropping by 100 rpm, but this did not work and blew the field winding fuse (yes you are right the motor is def not permanant magnet) Anyway so then I reduced the drop down steps to 50 rpm, this worked but it was borderline?, I could hear the spindle motor groaning under the strain,

Your point about the tacho? how would it become damaged? is it possible to have worn? is it difficult to check?

I an still not sure about a braking resistor, I cannot see or locate anything on the scale you are talking about, I think the spindle has regenerative braking controled by the Contraves spindle drive,

The Rc network is something I was looking at on the Schematics of the Contrave drive (Something I would like you to look at) this is an area I might be able to make changes because as you say the machine is in my home workshop and I am not looking for milliseconds/seconds or even minutes, just want the thing to run!.

There is definatly no deceleration control on either the Tnc or the Contraves, I can adjust the "LIN" pot for a gentle accel, but no adjustment for decel?. There are several trim pots on the Contraves: spindle current/Max spindle speed/accel ramp/tacho trim/zero speed/Armeture voltage feedback/ and more,

I have managed to download a manual for the Contraves drive and I am picking my way thro it making sure everything is set to how it should be,

I have to admit to not understanding some of the points you have listed, I wish I had a greater electrical knoledge so as to be able to go a bit deeper, but I know my limits,

I am very greatfull for your very discriptive input, Thanks for any ideas you may think of in the future,

Allen.

[Al_The_Man]

You may not need to get too concerned, I would imagine a drive of that calibre would have field loss detection.
Also it should have tach loss detection, sense it, and go into error?
I could be wrong, but I suspect that if the drive is full wave SCR, the braking will be regenerative in a four quadrant style rather than resistive?
It is usually PWM and drives that incorporate a DC supply such as VFD's usually take advantage of resistive braking.
There is anomaly there as to why the field fuse blew? Deceleration does not usually impact on the field?
Do you have a link for the manual?
Al.

[moonman5]

You may not need to get too concerned, I would imagine a drive of that calibre would have field loss detection.
Also it should have tach loss detection, sense it, and go into error?
I could be wrong, but I suspect that if the drive is full wave SCR, the braking will be regenerative in a four quadrant style rather than resistive?
It is usually PWM and drives that incorporate a DC supply such as VFD's usually take advantage of resistive braking.
There is anomaly there as to why the field fuse blew? Deceleration does not usually impact on the field?
Do you have a link for the manual?
Al.

Hi Al,

Thanks again for your input, I would say that you are correct about the regenerative braking, I have done some research of my own and suspect is the braking is four quadrant, I feel sure it is not resistive.

I have the link for the Contraves Varidyn manual it is very informative and quite a large file with loads of information/procedures/checks/schematics, I had a few attempts to download it (although you can read it directly online), I feel that this would be very usefull to someone of your calibre, it is clear you have a good understanding of this type of thing, so I will be looking forward to any ideas you may have (Glass ready!)

The Link: (note: it is the very top pdf file "Conlreet - contraves drivesoperating manual. manuel de mise en service. compact vdb. i serte 2oo i. | 200 sefres," )
Operating Manual Contraves Adb F 415 30 lists of files PDF operating manual contraves adb f 415 30

Thanks again for any help,

Allen

Operating Manual Contraves Adb F 415 30 lists of files PDF operating manual contraves adb f 415 30

[Al_The_Man]

Perusing the manual, something else comes to mind from working on similar Siemens drives, the manual states that 'do not switch off under load as it may result in blown fuses'.
I know from experience that when these drives are operating and a power outage occurs, it result in a loss of the main fuses.
If the back emf of the braking results in a momentary collapse of the generated phase, this could account for it.
The firing circuit for the SCR's take a sample of the incoming phase in order to fire at the right time.
The manual states the power should be at ±10% at all times!.
Al.

[moonman5]

Perusing the manual, something else comes to mind from working on similar Siemens drives, the manual states that 'do not switch off under load as it may result in blown fuses'.
I know from experience that when these drives are operating and a power outage occurs, it result in a loss of the main fuses.
If the back emf of the braking results in a momentary collapse of the generated phase, this could account for it.
The firing circuit for the SCR's take a sample of the incoming phase in order to fire at the right time.
The manual states the power should be at ±10% at all times!.
Al.

Hi Al,
Yes I noted that to, so when the spindle decelerates it is causing voltage fluctuation, The Rpc manual quotes figures of +/-10% over the load rande of L1/L2/L3, so no room for error.

I am kind of stuck now, as I have always thought the Rpc seems to be the heart of problem, I think that under braking the spindle motor is creating electrical energy (regenerative) and the wild leg cannot cope with it and puts more power into the two real legs?

Have you any ideas of how I might be able to get over the problem, one member has sugested taking the three phase from the Rpc and putting it thro a three phase inverter/Vfd, will this not give me the same problem?.

Allen.

[Al_The_Man]

Have you any ideas of how I might be able to get over the problem, one member has sugested taking the three phase from the Rpc and putting it thro a three phase inverter/Vfd, will this not give me the same problem?.

Allen.

You may get another problem using the VFD to supply a SCR drive, these drives usually expect to see a clean 3ph signal, the VFD output, although a reconstructed 3ph sine wave, is made up a from a PWM signal, of which the drive may not like to see.
Al.

[moonman5]

You may get another problem using the VFD to supply a SCR drive, these drives usually expect to see a clean 3ph signal, the VFD output, although a reconstructed 3ph sine wave, is made up a from a PWM signal, of which the drive may not like to see.
Al.

Hi Al,

Yes I did have my suspicions about that idea, what do you think about changing the phase possitions, or will this just move the problem to another line?.

I really cannot see a way out of this problem, I'm just confused how others on the forum are managing to run the same type of machine on Vfd.s and Rpc,s?

Allen.

[Al_The_Man]

I don't think swapping the phases will help, you could try at this point, nothing to lose!
Do the others have a Contraves drive? If you can find someone here or other forums that had success with this drive, it could be the only hope?
Al.

[moonman5]

I don't think swapping the phases will help, you could try at this point, nothing to lose!
Do the others have a Contraves drive? If you can find someone here or other forums that had success with this drive, it could be the only hope?
Al.

Al, lets take the worse case scenario, Say I get rid of the contrves completly, can I run the Dc spindle from a Vfd then?

Al

[Al_The_Man]

DC spindle cannot be ran from VFD (3ph AC).
Must be a DC drive.
I see someone in another forum suggested a PhasePerfect instead of RPC due to supposedly it handling back EMF in braking.
No confirmation on this so it may be a pricey experiment!
Al.

[mflux_gamblej]

I've got a 20HP rpc built from a GE 20 HP 3ph motor (a big sucker), and a phase craft brand rpc capacitor setup that I bought on ebay. I support the guy who builds these phase craft rpcs, mine is great, handles the back emf from braking with no trouble.. he's good on support too, he'll answer his cell pretty much anytime. once i got my rpc setup and the phases in the right order, i've been running with no trouble related to power.

maybe your RPC isnt big enough? my mk 2 has a 9.5 HP motor. everyone says that you need a 2x sized rpc to run a CNC machine.

my rpc setup ended up costing me around 500 (motor) + 350 (rpc stuff) + 300 (wiring, breakers, boxes, etc). I think that this is very cheap compared to the other rpc's out there, especially the 'cnc grade' ones. whatever that means... the phase craft one that i got says its cnc grade, but isnt insanely expensive.

I realize that i've given a shameless plug for phase craft rpcs here, but i'm not associated with them at all except that i bought one, and he earned it - good rpc

[moonman5]

I've got a 20HP rpc built from a GE 20 HP 3ph motor (a big sucker), and a phase craft brand rpc capacitor setup that I bought on ebay. I support the guy who builds these phase craft rpcs, mine is great, handles the back emf from braking with no trouble.. he's good on support too, he'll answer his cell pretty much anytime. once i got my rpc setup and the phases in the right order, i've been running with no trouble related to power.

maybe your RPC isnt big enough? my mk 2 has a 9.5 HP motor. everyone says that you need a 2x sized rpc to run a CNC machine.

my rpc setup ended up costing me around 500 (motor) + 350 (rpc stuff) + 300 (wiring, breakers, boxes, etc). I think that this is very cheap compared to the other rpc's out there, especially the 'cnc grade' ones. whatever that means... the phase craft one that i got says its cnc grade, but isnt insanely expensive.

I realize that i've given a shameless plug for phase craft rpcs here, but i'm not associated with them at all except that i bought one, and he earned it - good rpc

Hi mflux_gamblej,

Thanks for your reply, I take your point on Rpc size, I have a "Booster" (Tm) Rpc 12kw, my machine an interact 1 Mk2 has a 6.5 Hp (4.7 Kw) spindle motor so I think I am well within the power range required, You have mentioned "Phasecraft", I believe and have read that these are very good units, thing is as Al said it's a big gamble to take just to prove a point, I need to loan one and try it on my machine first, I still feel that my problem is with the Scr spindle drive unit, this is what does not like the Rpc, Have you got Scr drives on your machines?,

I still have one more chance left? I am going to try changing the phases around as Gus mentioned earlier, you never know perhaps the wild leg in another possition may help?

Thanks again for your input,

Allen.

[mflux_gamblej]

Hi mflux_gamblej,

Thanks for your reply, I take your point on Rpc size, I have a "Booster" (Tm) Rpc 12kw, my machine an interact 1 Mk2 has a 6.5 Hp (4.7 Kw) spindle motor so I think I am well within the power range required, You have mentioned "Phasecraft", I believe and have read that these are very good units, thing is as Al said it's a big gamble to take just to prove a point, I need to loan one and try it on my machine first, I still feel that my problem is with the Scr spindle drive unit, this is what does not like the Rpc, Have you got Scr drives on your machines?,

I still have one more chance left? I am going to try changing the phases around as Gus mentioned earlier, you never know perhaps the wild leg in another possition may help?

Thanks again for your input,

Allen.

Does your machine have the contraves, or the KTK drive?

I am sure, per the 'operators' manual (i.e. not the maint. manual, there are two manuals available for this machine) that your spindle motor is also 9.25 HP (7 kW). This should be shown on the motor plate too. The operators manual lists the specs for the interact series 1 and 2, mk's 1 and 2. (4 different machines). Our machine the interact 1 mk 2 has a 9.25 hp italian made green painted DC spindle motor. From what i can tell (based on my spindle troubles) these motors are pretty much indestructible. Your motor control will eat itself alive before the actual motor does. Interestingly, the same operators manual says that the machine has an effective 6.5 hp rating. I assume that this is the usable hp when milling (think 3" facemill in 304 stainless at low rpm). The machine maintenance manual calls for 12 kW service to the machine overall (spindle + servos + control, etc). This would be 240V, 50A (16 HP). I have 240v, 70A rated wiring, because my rpc is 20 HP and the start current can be high (ive measured it at 45 amps, but thats with the readout from a fluke clamp meter and cannot be trusted to display the instantaneous peak current).

I don't know that your rpc is undersized, but id say that you're pushing it for starting currents and maybe even for milling. I have measured my machines current use though - for example milling 304 ss with a 1/2" endmill, 34 thou depth. It uses 6.14 kW (8.23 HP) under those conditions. That includes the load caused by the rpc too. So the machine isn't using the max HP under heavy milling conditions.

In my experience our machines' casting and/or spindle mechanics cant take the vibrations and bending for the rated motor HP. you cannot facemill ss with our machine (3") without making one hell of a vibration that is surely damaging to the machine but the motor itself has no trouble with it at all. The manual says that we can mill 2 cu in. in mild steel per minute - I haven't considered the implications of this spec on my facemilling example though.

If the phases are backwards your motor controller will give an alarm with one of the LEDs on the board. I think its actually labeled 'phase'. (KTK drive). the spindle shouldnt run at all if you have the swapped at the mains. if the wires are swapped at the motor itself, then the air moved by your blower motor on the spindle motor will be pulled into the top of the motor and pushed out the bottom. If the phase is right, the air will be pulled into the bottom and pushed out the top. put a piece of paper up against the blower intake (bottom of blower) it should get sucked up against it.

I have the KTK drive and it is rock solid. The MTI1 board (interface between the heidenhain, motor, and KTK drive) is a piece of sh*t though. check all of the diodes and caps on that board. ive also heard of blown transformers on that board. read my previous forum on testing SCR's on the KTK and MTI 1 board. there's enough info there to get you started.

PM me and I'll send you the notes that i have on the KTK drive (i cannot help with contraves). these notes were provided by george (machinetek) who is an invaluable resource for bridgeports, and CNC machines in general. I also have the manuals, but I paid for them, so I'd sell them to you at 1/2 price (to divide the cost between us). it'll cost you a whopping $15 or so.

good luck out there man, this spindle drive haunted me for 2 months, and i expect it to again in the future. that said, i've been making parts for 3 months now, and am having a great time with the machine. it holds tolerances very well (linear encoders be dammed!) and repeats very well. I am impressed with this machine and think that the heidenhain 151B is WAY ahead of its time.

[moonman5]

Does your machine have the contraves, or the KTK drive?

I am sure, per the 'operators' manual (i.e. not the maint. manual, there are two manuals available for this machine) that your spindle motor is also 9.25 HP (7 kW). This should be shown on the motor plate too. The operators manual lists the specs for the interact series 1 and 2, mk's 1 and 2. (4 different machines). Our machine the interact 1 mk 2 has a 9.25 hp italian made green painted DC spindle motor. From what i can tell (based on my spindle troubles) these motors are pretty much indestructible. Your motor control will eat itself alive before the actual motor does. Interestingly, the same operators manual says that the machine has an effective 6.5 hp rating. I assume that this is the usable hp when milling (think 3" facemill in 304 stainless at low rpm). The machine maintenance manual calls for 12 kW service to the machine overall (spindle + servos + control, etc). This would be 240V, 50A (16 HP). I have 240v, 70A rated wiring, because my rpc is 20 HP and the start current can be high (ive measured it at 45 amps, but thats with the readout from a fluke clamp meter and cannot be trusted to display the instantaneous peak current).

I don't know that your rpc is undersized, but id say that you're pushing it for starting currents and maybe even for milling. I have measured my machines current use though - for example milling 304 ss with a 1/2" endmill, 34 thou depth. It uses 6.14 kW (8.23 HP) under those conditions. That includes the load caused by the rpc too. So the machine isn't using the max HP under heavy milling conditions.

In my experience our machines' casting and/or spindle mechanics cant take the vibrations and bending for the rated motor HP. you cannot facemill ss with our machine (3") without making one hell of a vibration that is surely damaging to the machine but the motor itself has no trouble with it at all. The manual says that we can mill 2 cu in. in mild steel per minute - I haven't considered the implications of this spec on my facemilling example though.

If the phases are backwards your motor controller will give an alarm with one of the LEDs on the board. I think its actually labeled 'phase'. (KTK drive). the spindle shouldnt run at all if you have the swapped at the mains. if the wires are swapped at the motor itself, then the air moved by your blower motor on the spindle motor will be pulled into the top of the motor and pushed out the bottom. If the phase is right, the air will be pulled into the bottom and pushed out the top. put a piece of paper up against the blower intake (bottom of blower) it should get sucked up against it.

I have the KTK drive and it is rock solid. The MTI1 board (interface between the heidenhain, motor, and KTK drive) is a piece of sh*t though. check all of the diodes and caps on that board. ive also heard of blown transformers on that board. read my previous forum on testing SCR's on the KTK and MTI 1 board. there's enough info there to get you started.

PM me and I'll send you the notes that i have on the KTK drive (i cannot help with contraves). these notes were provided by george (machinetek) who is an invaluable resource for bridgeports, and CNC machines in general. I also have the manuals, but I paid for them, so I'd sell them to you at 1/2 price (to divide the cost between us). it'll cost you a whopping $15 or so.

good luck out there man, this spindle drive haunted me for 2 months, and i expect it to again in the future. that said, i've been making parts for 3 months now, and am having a great time with the machine. it holds tolerances very well (linear encoders be dammed!) and repeats very well. I am impressed with this machine and think that the heidenhain 151B is WAY ahead of its time.

Hi mflux_gamblej,

Again thanks for your reply, The machine is fittrd with the Contraves drive and I think this is why I am having problems with this particular machine, I have taken the identification plate from the motor and it reads:

TYPE: GK80-20BF9, 6.9 H/P, 4,7 K/W , ANKER/ARM 400 VOLT 13.6 AMPS.

I kind of think that this is not the original motor as it is painted in red oxide and does not match the spec in the book?, as you said it shows the machine fitted with a 9.25 H/p motor?, I remember the green Italian motor I changed one of these years ago at a place I worked fitted to exactly the same type/year machine.

I do have a lot of info about the contraves drive, set-up/schematics/procedures etc,

I take your point about Rpc size, but I am having problems before I even cut metal, It's not starting the spindle or even cutting metal that is the problem, the machine blows fuses when the spindle stops from high revs (anything above 1000 Rpm) If I could stop the regenerative braking i'm sure my problems would be solved, I just dont think the Contraves spindle drive can cope with the back emf?.

I agree with you entirely about the Hiedenhain 151 being before it's time, this was the first Cnc machine I programmed and opperated when I was younger, so when one came up cheap near me I had to buy it!, just want to get some use out of it and maybe earn a little to,

I currently run a Fully simultaniouse 5 Axis Dmu 70 Evolution, a very clever machine, but I like the basics of a small Interact, bloody good machines for there time.

Allen.

[moonman5]

I have give up trying to solve my problems with this machine, I have come to the conclusion that the RPC is the main problem,..so the Rpc is up for sale and will have to go, I am pretty sure that the Rpc cannot cope with the regenerative breaking becuase of the false/wild leg.

Nothing I have done has worked, I have got thro a shed load of fuses and feel that this cannot be doing the machine any good.

So now I have another question?,

Is it possible to run this machine from a diesel generator (fitted with an AVR unit)? or will I get a different type of problem?

Thanks for any advice/help.

[Al_The_Man]

Wouldn't it be more prudent, not to say quieter, to fit a 3 ph motor and VFD off of 1 phase?
You could recoup some of the cost from the drive and motor sale?
Al.

[moonman5]

Wouldn't it be more prudent, not to say quieter, to fit a 3 ph motor and VFD off of 1 phase?
You could recoup some of the cost from the drive and motor sale?
Al.

Hi Al,
Thanks for your reply..Again! Yes I have thought of going down that route, it would be easier and possibly cheaper? But! what about the axis servo drives? do they not need 3 phase? or are you thinking of keeping the Rpc for the drives and the Vfd for single phase motor? Also what about tourqe on a 3 phase motor, will it not stall under load?.

I just thought that at least a 3 phase generator is the nearest thing to the real thing?, I am worried I might create new problems with a Vfd and a 3 phase motor?

Your thoughts........