Denford Software & Machines

Having had some issues with connectivity (documented in a QuickCAM thread, I’ve had some success… yay!)

I can now connect to and drive the axis from the laptop.
This includes by home and jog functions.
I can operate coolant pump etc, so machine and laptop are talking.

I’m struggling with the spindle though…
When activated, I can hear a solenoid/switch flick inside the control box, but nothing happens at the machine…

Any thoughts on where to start investigations??

Thank you

Does the red power light on the Sprint 1200 spindle drive light. It may be as simple as a fuse.

Is it the LEDs at top left that you mean? Or somewhere else?
I’ve not had chance to fire up this week, but will try over wknd!

Martin,
Neither of the red LEDs illuminate…

If the ‘on’ LED isn’t illuminated, is it possible this is a power supply (to the sprint drive) issue, rather than an issue with the drive itself?

The fuse on the drive is fine, but are there others ‘up stream’ that could be causing the issue?

I found the attached ‘post-it’ in a manual that was supplied with the machine… so the spindle fault was a pre-existing condition it seems!
(I’ve never had it running since I bought it).

Found 10A fuse #F1 was blown.
Swapped out and restarted machine.
Spindle ramped up to high(ish) speed immediately (before even referencing the axis), at same time the fuse blew again.

Any thoughts?

*edit* rechecked and the fuse I replaced the 10A with was only 3.15A!
Will get some more 10A and retry ASAP.
Is it common for #F1 to blow?

What speed did you ask for?

It may be you have an issue with the Tac. If it still ramps u when you replace the fuse try changing the dip switch on the drive from Tach to AVF mode.

Thanks for replies guys
(I’ve also got the thread running on the mycncuk forum…)

I changed for a new 10A…

Upon firing up the machine, the spindle ramps up to full revs and back down, to approx. 60-100revs, and stays there.
I’d not commanded any rpm at this stage.
Once I reference the axis, I can stop and restart the spindle in manual mode, but can’t change the rpm??
I’ve tried with the electronic ‘pot’ and electronic override ‘pot’ (I don’t have a physical pot for either).
I rebooted the machine and the same occurred…
I get 200mV across wires #54 & #55 at all revs.

Could defective brushes cause this?
Or more likely to be a drive issue or other?

I’ll try the tac/avf switch tomorrow…

If this works, is it safe to leave it?
Or, does it mean a new tacho, or other?

Update:

With slider at TAC = spindle fires up to high revs and sometimes trips my supply RCD!
If it doesn't trip the RCD, I can usually (not every time) start/stop the spindle in VR5, but not alter rpm.
With slider at AVF = spindle fires up to lower revs (1k rpm?) then stops.
I am not able to start/stop the spindle in VR5.

Wires #54 & #55 removed from Sprint1200 = spindle does fire at all
Wires #54 & #55 linked out on #1 & #3 connector on Sprint1200 = same as with #54 & #55 in position (incl same with the TAC/AVF slider)

At startup, both TAC/AVF, I measure 11.5v across #54 & #55

The only spindle settings I can see in VR5 are max/min rpm, and check boxes for manual, speed pot & external speed pot...

Help!

The two Blue wires with the numbered tags on them that are in positions 2 and 3 in the Green connector at the bottom of the drive shown in your photo are the 0~10v Analog input to the drive, depending on what spindle speed is selected this voltage changes, normally the Max spindle speed on a Triac is 4000rpm for the full 10v so if you disconect the wires from the drive and set a spindle speed of say 2000rpm via your MDI and measure the voltage you should have 5v at that point, if you have the correct voltages for programmed spindle speeds the the input is OK and you will likely have a "duff" Sprint Drive.
If the input from the main board is not OK at the input point of the Sprint drive then you likely have a Main board issue that is not outputting the voltage for the Spindle drive, I am not familiar with the Denford hardware for the VR software so wouldn`t like to guess at a diagnosis, contact Denford is probably best if that seems to be where the issue is.

These old drives are easily damaged as they were a "non-isolated" type, the new version of that drive is fully isolated and last I checked was about £260 direct from Sprint Electric, Model number for use in the Triac is the 1220, that is what I used when I had to replace one and it has worked perfectly, link to Sprint website for the drive. Looks different but the connections are the same
https://www.sprint-electric.com/product ... 20-series/

Spent a short amount of time, doing some more investigation tonight…

When booting up mill and spindle ramps up, SGR is NOT energised.
With SGR removed, spindle still goes rogue and ramps up on its own!
Removed #54 & #55 from green bar at lower end…
With spindle stopped, 180mV across terminals.
176mV @ 1000rpm
182mV @ 2000rpm
185mV @ 3000rpm
185mV @ 4000rpm

Haven’t got a 10k pot yet for other tests, but will do so soon.

There is an intervening Baldor board.
I’m waiting for Sprint to come back with some more info/prices…
I happy to go with either the 1200 or 1220i… they aren’t ‘megabucks’, but if it’s the Baldor board, it could still be a waste of cash… so still trying to prove what’s what.

You can easily test the Sprint drive by disconnecting the 54/55 input wires and using a battery of say 1.5 volts to put a put a safe voltage to the Sprint input you should get around 600rpm, if that works then the Sprint is probably good.

I am a bit puzzled what the two Blue wires at the top of the drive in your photo, I have never seen any wires connected like that on any Sprint drive on any machine, suggest you ask Denford what they are for.

Buying one of the new type Sprint 1220/1220i will never be a waste of money IMHO.

Lone_Ranger wrote: ↑

Mon 04 Oct , 2021 23:03 pm

I am a bit puzzled what the two Blue wires at the top of the drive in your photo, I have never seen any wires connected like that on any Sprint drive on any machine, suggest you ask Denford what they are for.

They're connected to the stall detection output from the Sprint drive.

Everything I’ve checked has been in line with electrical diagrams… not checked everything, but everything I have has been correct.
Spindle activates with 51/53 removed.

Disconnected 54 & 55 from Sprint and fitted a 10k linear potentiometer;
Spindle fires up as machine boots up (incl. with SGR removed).
@10k, spindle was running at approx 1k rpm (by eye/estimated)
@9k & less, spindle increases in rpm rapidly
I.e. NOT 10k = 250rpm / 5k = 2000rpm / 0k = 4000rpm
More like, 10k = 1000rpm / 9k = 2500rpm / 8k = 4000rpm

Increasingly looking like both the Sprint drive and Baldor board are both dead..?

Sprint boards seem readily available, but anyone know of any Baldor boards? (Doubtful I know…)
Other options…?

Hi all - thanks for the help & support in identifying the issue with the spindle drive

I sent the drive to Sprint, who were super-helpful by the way, for investigation prior to repair or replacement.
It proved not cost effective to repair and the 1600i was recommended as the replacement.
A couple of hours making up a new mount (as it’s bigger than the 1200) and wiring in and we were in business!
No ‘rogue behaviour’ from the spindle on boot up and no tripping the power!

I’m still apprehensive about wiring into the mint board, in case that’s what killed the old 1200.
So I’ve wired in a 10k pot and now have control and functionality of the spindle

Still have some comms issues, so a separate post to follow…

I am also having issues with the spindle not running after a recent crash. These fuses are ok are they any others I've missed?

You need to unscrew the caps

That's great Martin all fixed thank you. I didn't even know they were there