Multiple fuses blowing

[Kholden]

Customer issue:

When the customer turns on the machine they are blowing several fuses over and over again.

This is a micromill that was built in the US (1996). It appears from the customers description that the fuses blowing are attached to the mains and transformer. They are also blowing the fuse on the Nextmove (w/ USB) from time to time.

I am wondering if there is more likely a problem with the mains power or could it be the transformer going bad.

Any suggestions would be great.

[Steve]

We need more detail.

You say the customer is blowing fuses. does this mean the same fuse multiple times or more than one fuse at a time?

Does the machine ever work? Do the fuses blow at once or does the machine run for a bit first?

To fault find this if it is the fuse to the primary of the transformer that is blowing, Try removing the fuse from the secondary then power on again. If the Primary fuse blows then the fault is in the transformer. If it does not measure the secondary voltage and check it is correct.

Power off, Replace the fuse then press the E-stop. Power on. If the fuse does not blow release the E-stop then see if the fuse blows.

The E-stop release adds motor power to the nextmove.

Disconnect the Nextmove power supply (TB11) then power on. Does the fuse blow? If not plug in the Nextmove and try again. If it blows as the nextmove is connected try disconnecting all the plugs to it and try again.

If the fuse blows with only TB11 connected the fault is on the Nextmove.

If it does not blow with TB11 alone connected start plugging the other connectors in to find what is causing the problem.

Let us know how you get on.

[Kholden]

The fuses were F1 and F2 from the transformer and if they were slow at blowing, then F5 on the Control Card.

With the power turned on, F1 connected, the machine would blow the fuses as soon as F2 was connected.

Transformer was replaced and machine functioned normally. Machine was run non-stop for 45 minutes and cut a test piece 4 times.