R702 HiPrint (2008): HA: Phase failure

We have a 2008 R702 3B P 1/1 HiPrint that blew L1 and L2 F091 fuses this morning. The fuses were replaced, and the main motor mains conductors were checked for grounding and shorts from the fuses to the drive. After energizing the press, it currently runs but when a stop pushbutton is used the press stops fast and throws a HA: Phase failure fault. Sometimes there is an additional fault about the main motor armature. The drive is a Baumuller BKF 12. It always displays fault 14 (lost mains) and occasionally fault 17 (lost armature) during these events. Fuses are all good. Checked conductor connections on the mains from where it enters the cabinet to it enters the drive. There is a filter, line reactor, fuses, and contactor in the line. Took the contactor apart and checked the points on the contacts and checked for continuity between each set of contacts. On the armature side of the drive, I checked the conductor connections. The mains contactor K050 has 2 N.O. auxiliary relays, both check good. Checked continuity of the armature windings cold from the drive and after the fuses, both read 0.5ohms. Cold field windings displayed 124.5ohms. Running the press without sheets being pulled the mains pull 19A, armature 22A, and field 1.8A.

I was checking out the cabinet side of things while a coworker checked at the motor. He states that the brushes are good. Cable connector from the cabinet is tight and locked down. He opened the motor pecker head and the connections inside were good and he checked the armature and field windings there and his readings were almost exactly what I had.

When run is pressed the mains contactor K050 energizes and a couple of seconds later the press starts up. When stop is pressed it seems like the contactor is de-energized before the press stops moving.

Does anyone have an idea of what I need to look at?

2022-10-11 - Changed aux N.C. to N.O.

 

I have faced this type of issue, I spent 5 days on it checked all connections, motor, contactor.
In startiy phase failure issue came in plate loading or inching. After some time it came frequently and at last machine stops.
After all identification s we changes Eprom of UWR and then problem solved.

 

When you press normal stop machine react like fast stop?

 

No it was normal.
But frequently was giving HA phase failure error.
After somedays press stops and when we gave run command main contactor hold and then unhold with error HA phase failure

 

OK, but i ask for R702 machine, for your problem check my theard R300 problem, it was similar, problem was in signal generator board...

 

hello
you mentioned K050 has 2 N.C but I think it has N.O contact used, please check it again

 

This is correct. Normal stop is pressed and the press stops quick with a clunk sound.

 

You are correct. I wrote that wrong.

 

Hmmmm.... I had similar problem on R500, but R500 does not have BKF12. Problem was in encoder reading board in main drive. You also have two encodrs, one is connected to RTR and another to BKF, try check them, maybe one is sending wrong signal and machine can not read real speed....
Try to do speed alighment check, turn switch on RTR to 5 and set idle run to 3000, 6000 and 9000. Watch two 7segment displays on this board, they should be near or zero....

 

K050 should not de-energize until the machine stops normally when you pressed the safe stop button. so, for me, the auxiliary contacts of the main contactor K050 are the first remedy then the K1 relay of BKF12 and power output for auxiliary contactor K252

 

Phase failure is coming because K050 deenergized in a fast way, it means some safety issue turn off K050, if UWR reacts then we asume it is a safety problem!!! Check the adjustment for the microswitch to control the brake, the other thing you should verify is the internal relay K3 at main drive for the activation of brake release

 

The K1 relay on the board isn't holding K050 in until the press reaches 0 speed. I added a time off delay circuit to simulate K1 to hold in K252 and K050 until the press stops. Due to the drive being repaired a year ago and some other issues management has opted for a drive upgrade which I ordered today. I'll then have this one refubbed for a spare for another press.