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Author Topic: Lathe spindle brake  (Read 13103 times)

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Offline Hood

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Re: Lathe spindle brake
« Reply #10 on: August 19, 2009, 04:52:29 PM »
You did not mention what kind of spindle motor/controller it is?
Did it previously brake to a stop, or was it just a holding brake?
If it was a holding brake, there must have been some method or signal to indicate zero speed?
Nosmo.

I think it was just a brake that was spring loaded so when you shut off the power to the  spindle the electromagnet  lost power and the brake clamped, that is the normal way on the Colchester manual lathes anyway.

Hood
Re: Lathe spindle brake
« Reply #11 on: August 19, 2009, 05:39:29 PM »
So it sounds like just braking a normal uncontrolled AC spindle motor. What is the reason for the time delay if the original worked OK?
Nosmo.

Offline Hood

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Re: Lathe spindle brake
« Reply #12 on: August 19, 2009, 06:08:42 PM »
Maybe Derek better clarify what actually hapens as I was thinking it was a manual lathe he was converting but reading again it seems it was a CNC originally.
 I was thinking he had fitted a VFD and needed the delay so that the brake didnt aply too soon thus tripping the VFD.
 As it seems to be working correctly (toggle Active setting) then I think it must just be the macro is in the wrong place for the profile, either that or its not correctly named..
Hood
Re: Lathe spindle brake
« Reply #13 on: August 19, 2009, 09:20:53 PM »
On a VFD that has configurable outputs , I have set one for 'At Zero Speed' this can be used as a software input or switch hardware direct.
Nosmo.
Re: Lathe spindle brake
« Reply #14 on: August 19, 2009, 10:25:54 PM »
What bob are you using?Are you starting the spindle from relays on the bob or from a plc?
Re: Lathe spindle brake
« Reply #15 on: August 20, 2009, 02:43:31 AM »
Hi All,

Thanks for the help....

It is a CNC lathe that myself and brother are upgrading. (Old anilam crusader control)
The brake originally released and came back on in time with the spindle start signal. The spindle motor control was just a contactor / DOL system and now has a VFD so I wanted to get the VFD to apply its share of braking (softer deceleration than applying the brake at full chat) and also as Hood stated prevent the drive from tripping.

I am 'sure' (as I can be) that I am using the correct macro, I can set the delay to say 3000 (3s) and I see a delay in the start, set this to 100 and I see a much shorter delay. Also I deleted all the other profiles to be sure.
Profile I am using is Colchester - C:\Mach3\Macros\Colchester

BOB is a PMDX122 ( I have fitted this type to my BP mill and Orac lathe - good kit, the PMDX)
The spindle start signal from the BOB feeds a Homan Designs DC-06 speed controller. The relay on the DC-06 starts the spindle - this works fine.
An output from the BOB feeds a SSR that operates the brake. The SSR has a LED to show operation, this switches on as I toggle the ports and pins active hi/low but wont be controlled by the macro.

Just a point, might be unrelated, I did have the charge pump working but now I can't get the charge pump relay to operate - "fixed with a chock block for now" (my Estops still work :o)
Haven't tried this yet  if you open the macro in the editor and press the green arrow does it work?

On a positive note, I got the viper 200 drive powered up on the Z axis, and can talk to the drive to tune the parameters - motor holds position - at least no expensive smoke  ;)
I have not been able to command a move yet, drives are not getting or ignoring the step signal...it was late last night when I tested this and thought best to have a rest and have a fresh go in the morning.
I will get a scope on the OP of the BOB to see if there is a pulse train.

I'm sure when we get to the bottom of this, there will be a need to "issue an idiot alert warning" as its bound to be me that has done something silly :-[

ATB
Derek.
« Last Edit: August 20, 2009, 02:57:13 AM by derekbpcnc »
You can "chop it off" but can't "chop it on"

Offline Hood

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Re: Lathe spindle brake
« Reply #16 on: August 20, 2009, 03:44:53 AM »
If you want to attach your xml and also the macros I will have a look here and see if I can find a problem. You will be best to xip them in one folder just in case it is a naming problem.
Hood
Re: Lathe spindle brake
« Reply #17 on: August 20, 2009, 05:12:47 PM »
Hi Hood,

Looks like the PC is throwing a wobbly.
Got the Z axis vipers working and the machine moving and did a bit of tuning but the motion was lumpy as hell.
I ran the driver test and the performance is terrible.... and crashed twice.
Also crashed when exiting the Config table.
So this could be the problem. I'm sure this is the cause of the charge pump not brining in the relay too.

Quickly coppied the xml to another PC, motion now smoooooth ( didn't check the Charge pump relay)

Me brother is going to re-install everything / check latest drivers and we'll give it another go.
Hope this will fix the macro problem too...

ATB
Derek
You can "chop it off" but can't "chop it on"
Re: Lathe spindle brake
« Reply #18 on: August 21, 2009, 01:35:58 PM »
Hi,

The PC has a problem.
Everytime running the driver test - it says "pulsing too fast" then "pulsing too slow" and then the PC hangs.
The PC runs mach "OK" buit motion very lumpy.

It is a 1.6GHZ MSI KM2M -
Fresh install of XP with SP3
512Mb ram
The MOBO drivers have been updated / reinstalled
LAN disabled
USB enabled /disabled
Parallel port tried in every BIOS setting
No virus SW running
Windows update off
Task manager shows 99% idle
Was using onboard graphics and now fitted a Radion 9600 - no change.
Gone through the optimisation.

Any suggestions?......I'll start -

1) bin the MOBO

ATB
Derek.


You can "chop it off" but can't "chop it on"

Offline Hood

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Re: Lathe spindle brake
« Reply #19 on: August 21, 2009, 02:29:11 PM »
You tried the optomisation steps detailed on the downloads page?
Hood