2005 MINI MILL

[dougtyler]

My Mini Mill is getting a #292 - 320 volt power supply alarm.
When I look at the power supply, the code is "A" ( phase fault)

This is the only alarm that is coming up.

Anybody have any experiance with this one?

Thanks,

[X_HAAS_FSE_Jim]

In the upper right hand corner of the electronics cabinet there is a power card. It has in the top center of that board 3 fuses. Just to the right of each fuse is a light. If any of the lights are on the fuse is blown. If the fuses are good, check the incoming power. A Phase Fault means you have lost 1 phase of the incoming power.
Jim

[dougtyler]

No fuses blown. Checked the incoming power. 120 volts both legs.

[Donkey Hotey]

Take the fuses out of the board and make absolutely sure none are blown (indicator light or not).

I guess you could check the DC buss at the servo amps and see if you've got 320V DC (be very careful, 320VDC will make you very dead).

Either you have a blown fuse or a blown 320V power supply (the big box on the right side of the cabinet).

The parts in that box can be sourced outside of buying a whole new unit but, you'll need some troubleshooting skills to narrow down the component.

[dougtyler]

We'll the fuses are definately not blown.

[Donkey Hotey]

Do you have 320-ish volts on the DC buss (any/all the hot terminals on the back of the servo amplifiers +/-)?

Is the contactor closing on both legs?

Where exactly are you probing the 120V? Between each leg and neutral/ground? Before or after the breaker?

Are you sure that voltage is getting to the transformer? Is it coming out of the transformer and getting to the power supply box?

[dougtyler]

The High Voltage is not turning on.
I have 120 volts on each leg (240 volts total) going into the bottom of the power supply.

[Donkey Hotey]

Wait, you're saying you have 240V going into the power supply. You should have that much going into the transformer, then 325VAC going to the power supply.

Lets start over:

Here is the power flow (from memory, somebody correct me if I'm wrong):

1. Incoming power (should be 120V between each leg and ground)
2. Circuit Breaker (output side should be 120V between each leg and ground)
3. Three Phase Contactor (output side should be 120V between each leg and ground when the machine is on)
4. Transformer input rail / voltage taps (should still show 120V between each leg and ground when the machine is on)
5. Transformer output (should show 320-ish VAC between the two hot legs, going up to the DC Power Supply when the machine is on)
6. High voltage power supply (large box on the right side of the cabinet)

As already posted, you should measure 320-ish VDC on the output wires, going to the three axis amplifiers (+ and - terminals).

At which step above is something not behaving as I described it?

[dougtyler]

Well then I guess I'm talking about the transformer. However, it does plainly say "320 volt power supply" on the outside of the box.

[Donkey Hotey]

No, that's the power supply. The transformer is on the bottom of the cabinet.

[dougtyler]

Oh well, The service tech is on the way. I think I just heard my billfold pucker up.

[Donkey Hotey]

So it was the fuse, wasn't it?