If you have a MCB earth leakage trip fitted to your distribution incomingmains and it is this earth switch that is tripping, (voltage going down the earth wire) you have an electrical fault on the machine which is down to earth, you need a professional electrician of qualifiied service technician to check out the machine either with a PAT tester or megger.
At least you know you have earth protection.
PJW, February 2006