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VF1 -937 input voltage low alarm

sudtechcnc

Cast Iron
Joined
Mar 13, 2007
Location
chennai ,south india
Hello.
I keep getting this alarm.

Since the meaning seems clear enough, I checked up all the power cabling , breakers ,fuses etc before the machine main switch. every thing is fine.

Is any thing inside the machine causing this ?.

I was asked to check the DC bus voltage, Its 325 as recommended .

Can any body suggest any solution.

The alarm occurs about 10 to 15 times a day ( have to cycle the power to get machine started again)

Thanks
Mathen
 
Aside from checking the incoming power I would be on the phone with my Haas Outlet. If the person on the line can't help I'd ask for another who can.

I have had flaky power due to line connections outside the building, bad breakers and bad connections cause intermittent issues.

I had a problem awhile back and they had me adjust the voltage, but you already said your at he requested 325V, so I'm at a loss.
 
I see this occur in a few buildings where I do machine service and the incoming power supply to the building or the sub panel used by the facility is inadaquate.

In one example, a company uses a 480volt 3 phase subpanel supplied by a bit less than 200 amps. they run several machines from the subpanel and typically they get away with it. Simply put, it's rare that all the machines would start at the same time, or have high current requirements at the same time. Occasionally though, a few high draw items are required to start at the same time and odd things occur.

when to many demands are placed on the service, the voltage drops, current draw goes through the roof and things start to trip out or weld contactors shut.

I'd check the incoming power with loads from the other machiens on. It sounds like an incoming power supply issue perhaps.
 
Thanks Sim and stuart.

I did call Haas service . They suspected the Vector drive .
We swapped Vertor drives , and then the I/o card too. it had no effect.

The final swapping ( with a VF4) was the Mocon card.
Its been under observation for 4 shifts now . And the problem has not occurred on either
machine !!.

I t seems that may be a plug loose on the mocon.....

( but of course before we swapped the mocon I did try out the power change .
we did have 3 Haas mcs on the same feeder cable. but even after changing that .I had continued to get the alarm. which is when I called Haas)

Thanks
Mathen
 
Not sure if you worked out this problem yet but i have seen a loose feeder termination cause this alarm. Actually all the the way back at the main panel. I even put a scope on the feeders trying to find it with only a small dip but there was something there it did not like. Check EVERY connection from panel to machine.

You may also want to bump your transformer settings up to get about 335 volts on the DC buss. will not hurt it at all and actually helps performance of the TC.
 
Thanks viper.

Yes the problem got solved . we tightened every thing that resembled a screw inside the panel.

and the incoming power line. but as I remember we got the alarm even after that..

The problem seemed to have occurred soon after we moved the machine a few feet .
we dont usually hire any machinery for that , just the moving crew who place pipes below the machine and just roll it to position..then jack it up back on to the level plates/discs

and the problem got solved when we swapped the mocon card with another machien. which led us to believe that one of the 7 or 8 plugs on the PCB must have somehow got loose...

Thanks again
Mathen
 








 
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