Mining Hardware – How many amps can each stage withstand without damaging the transformer?

I have a 3 phase 250kVa transformer at my site.

The specifications of the label are as follows:

250kVa Cooling Type: ONAN Frequency: 50hz Voltage Rating: 20.000/400

My questions are:

How many 1phase, 220v, 3500 watt cryptocurrency servers can run simultaneously without damaging the transformers?

That is, the limit is reached, but how many amperes can each phase withstand without damaging the transformer?