Power Failure Detection Module

[1ctoolfool]

Does anyone know what exactly the Power Failure Detection Module option does and how it works.. and is it worth the $519?

I got this option because power frequently "blips" at my location. The UPS battery back ups on my PC's are always showing breif power losses every week.
How well does the HAAS handle this? Is this option just an isolation transformer to give a few more seconds of delay in the surge/lag of line power?

If not is there a way to UPS battery back up just the 110V or electronics portion of the control system? Didn't know how separate all this stuff is inside the cabinet.

Thanks
Joe V.

[Geof]

The Power Failure Detection Module is not just an isolation transformer. I had to get one installed on my gantry machine becasue the spindle would drop about 0.1 when the power was cut. The explanation below is more or less what the Hass tech told me.

On the Haas vertical spindle machines the Z axis does not have a counterweight in normal use when the servos are powered the weight of the axis sits on the servo; this is why the Z servo always shows a load that varies from around 25-30% for the MiniMills up to almost 60% for the gantry machines with the extended Z axis.

When the power to the servos is turned off a magnetic brake on the end of the servo motor locks down and holds the load. The brake is electrically released and power to release the brake must be turned off a miniscule time earlier than the power to the servoes so that brake is fully engaged before the servo stops supporting the load.

When E stop is hit to turn off the servo power the brake takes the load correctly before the servoes go off because all the power supplies are still producing power. However, when the power off button is pushed or when there is a power failure or blip down in the incoming power all the power supplies go down at the same time. Because there is some lag in the brake acting, when all the power goes down at the same time the Z axis screw can rotate a little before the brake locks down.

The Power Failure Detection Module monitors the incoming power and when it drops this module acts to keep the servo power up while the brake locks; or it kills the brake power immediately before the servoes go down. I don't know the exact operation but it is acting something like the E stop sequence.

[DEAN]

Yikes! HAAS does it again. You'd think that would be standard issue. To not have it standard seems like, for lack of a better example; A car without a emergency brake.

[Geof]

Yikes! HAAS does it again. You'd think that would be standard issue. To not have it standard seems like, for lack of a better example; A car without a emergency brake.

Yes and no. I have several vertical spindle machines without it and never had a spindle drop with a power failure. The gantry did drop but this has a 24" Z travel with high speed rapid so it uses a fast pitch ball screw. I think it should be standard equipment on bigger machines with high speed rapids.

[gar]

060816-0736 EST USA

1ctoolfool:

I have no idea what the "Power Failure Detection Module" is for, but Geof's description makes sense.

Some background.

Our 1993 VF has a counter weight on Z, our 96 and 98 VFs have nitrogen counter balance, and the 2000 uses the servo.

The spindle and servos all work from DC power supplies with reasonable size capacitors. These are charged from rectifiers from the AC line. Motors such as the coolant pump work directly from the AC line and float thru short power blips by inertia. The DC supplies float thru the blips based on the stored energy in the capacitors and maybe some from mechanical inertia. The larger these capacitors the longer blip you could tolerate. The electronic control also has energy storage capacitors.

Your program data is stored in battery backed memory that is write inhibited before the CPU would produce errors as the DC supply voltage drops. A conventional UPS would do nothing for you.

A couple years ago we were getting a lot of AC line voltage perturbations caused by a bad nuetral connection and one bad hot connection at the pole transformers. We had little difficulty on any of our machines. However, the 1993 machine can not tolerate as long a momentary drop in voltage as the others.

When we had the north east US power failure we had several fuses blow but no other problems.

A standard transformer will do virtually nothing for you relative to voltage variations, a large Sola type voltage regulating transformer would be useful for certain types of perturbations. The Sola would be prohibitively expensive and would not cover enough different types of faults.

A system I would like would be based on the following concept. A large alternator (same thing as a synchronous motor) with a large inertia load, a one way clutch and possibly another clutch, driven by a motor on the AC line. In addition there would be a quick start engine to supply power to the alternator under complete power loss. The goal is to provide totally uninterrupted power for any source perturbation, even multiday power loss. One might used the alternator as a motor floating on the line to eliminate a separate motor with a quick disconnect on power loss, but this does not provide the lightning protection that a separate drive motor would.

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[Geof]

....I got this option because power frequently "blips" at my location....How well does the HAAS handle this?.....Joe V.

I did not directly answer this question. My experience is that in general "blips" are handled quite well. Before upgrading our building supply and wiring we had loss of phase alarms fairly often; once a month or so for about four years. I think we only lost one tool and part due to this; most times the servoes dropped out before the spindle so the tools did not stall in the cut they just idled to a halt.

I took a picture of the time one machine did do something strange. The machine was running a block with a G02 from S to F with the next block having a tool comp cancel, G40, from F back to S ready for a second pass. When the blip happened it was most of the way around but then lost the G02 block and moved straight across to the coordinates in the G40 block; leaving the end of a slot cutter behind in the groove it was cutting. Then the machine alarmed out and shut down.

[gar]

060815-1225 EST USA

I believe that any time you get any sort of fault the servos will be almost immeadiately stopped. This would occur on a phase fault and maybe a low instantaneous input voltage, by instantaneous I mean greater than probably 8 to 10 milliseconds. HAAS is not clear on many details of how their machines work.

.

[Geof]

060815-1225 EST USA

I believe that any time you get any sort of fault the servos will be almost immeadiately stopped. This would occur on a phase fault and maybe a low instantaneous input voltage, by instantaneous I mean greater than probably 8 to 10 milliseconds. HAAS is not clear on many details of how their machines work.

.

This is my experience, servoes are killed very quickly. Actually a blip that is long enough to notice as fluorescent light flicker but too short for a PC UPS to kick in will shut down two or three of my machines while others will keep running.

This was what I found so intriguing with the picture I posted; the machine processor was disturbed enough to lose its place in the program but not enough to kill the servoes at the same time.