Here's the situation. We have a machine which uses two 100HP motors to drive hydraulic pumps. The first motor, M1, starts without an issue. The second motor, M1A, intermittently trips the breaker. When I observe the start-up, it starts fine in star (wye) but when it changes over to delta run, 1 in 10 times the breaker trips. We have changed contacts, mechanical interlocks and even coils. The motor has also been rewound once, as we believe this starting issue eventually caused the windings to short to ground. This problem has persisted since the machine was installed (brand new). The manufacturer even sent us all new starters and overload. The problem has still persisted.
Has anyone experienced a similar problem or have any thoughts that I may have overlooked?
Has anyone experienced a similar problem or have any thoughts that I may have overlooked?
