Hydraulic test apparatus and method for stator in electrical generator

A method for automatically drying a stator winding in a generator using an air compressor, air dryer, receiver and at least one automatic pressure activated valve, said method comprising the steps of:

• a. providing compressed air from the air compressor via the air dryer to the receiver which passes compressed air into the stator windings of the generator,
• b. pressurizing the receiver and stator winding with compressed air;
• c. when the pressure in the receiver or stator reaches a predetermined high level, automatically opening the pressure activated valve at an air outlet port for the stator winding to exhaust moisture and compressed air from the stator winding and receiver,
• d. automatically closing the pressure activated valve when the pressure in the receiver or stator falls to a predetermined low pressure substantially above atmospheric pressure, and
• e. repeating steps a through d to dry the stator winding.

A portable hydraulic dryer apparatus for drying a coolant passage within an electrical machine, said apparatus comprising:

• a portable frame,
• an air receiver carried by said frame and having an air outlet couplable to a first port of said coolant passage;
• an air compressor carried by said frames and coupled to supply compressed air into said air receiver;
• and
• an air pressure actuated valve couplable to a second port of said coolant passage, said valve controlled to open in response to air pressure in the air receiver or coolant passage exceeding a first value and being controlled to close in response to air pressure in the air receiver or coolant passage falling below a second value substantially greater than atmospheric pressure.

A stator hydraulic test and dryer apparatus comprising:

• an air compressor coupled to supply compressed air to an air receiver through an air dryer;
• said air receiver being couplable to a first port of water-cooled stator windings in a generator so that compressed air in said receiver is directed through said first port into said stator windings;
• a second port of the stator winding for exhausting pressurized air from the winding;
• a hygrometer including sensors, one of said sensors being positioned to monitor the compressed air entering the generator and a second of said sensors being positioned to monitor the air exhausted from said generator, and said hygrometer indicating the comparative dew points of the compressed air entering the generator and that of the air exhausted from the generator.

A method for automatically drying stator windings using an air compressor, air receiver, hygrometer sensors monitoring compressed air entering and exhausting from the generator, and an automatic pressure activated valve, said method comprising the steps of:

• a. automatically closing the pressure activated valve at an air outlet port of the stator windings of the generator, when the pressure in the receiver or stator falls to a predetermined low pressure;
• b. providing compressed air from the air compressor to the receiver which passes compressed air into the stator windings of the generator;
• c. pressurizing the receiver and stator windings with compressed air;
• d. when the pressure in the receiver or stator reaches a predetermined high level, automatically opening the pressure activated valve to exhaust moisture and compressed air from the stator windings and receiver;
• e. comparing the dewpoint as measured by the hygrometer sensors of the compressed air entering the generator and the air exhausting from the generator, and concluding the drying method after the difference between the dew points is less than a selected value, and
• f. repeating steps a through e to dry the stator windings until the method is concluded as set forth in step (e).

A stator hydraulic test and dryer apparatus comprising:

• an air compressor operatively coupled to supply compressed air to an air receiver through an air dryer and a first automatic valve positioned to isolate said compressor from said air receiver when closed;
• said air receiver couplable to a first port of water-cooled stator windings in a generator so that compressed air from said receiver passes into said stator windings;
• a second automatic valve coupled to a second port of the stator winding of said generator;
• first automatic valve being opened and said second automatic valve being closed when the pressure in said receiver and stator windings is below a predetermined high level;
• said first automatic valve being closed and said second automatic valve being opened when the pressure in said receiver and stator windings is at or above said predetermined high level to purge moisture and pressurized air from said receiver and stator windings, and
• said first automatic valve again being opened and said second automatic valve again being closed when the air pressure in said receiver and stator windings falls to a predetermined low level substantially above atmospheric pressure.

A stator hydraulic test and dryer apparatus comprising:

• an air compressor having a compressed air outlet operatively couplable to an air receiver through an air dryer and a first automatic valve positioned to isolate said compressor from said air receiver when closed;
• said air receiver having an inlet couplable to a first port of a water-cooled stator winding in a generator so that compressed air in said receiver passes into said stator windings;
• a second automatic valve couplable to a second port of the stator winding of said generator;
• and
• switch means for activating the automatic valves, wherein said first automatic valve is opened and said second automatic valve is closed until the pressure in said receiver and stator windings reaches a predetermined high level, at which point said first automatic valve is closed and said second automatic valve is opened to purge moisture and pressurized air from said receiver and stator windings, said first automatic valve being opened and said second automatic valve being closed when the air pressure in said receiver and stator windings falls to a predetermined low level substantially above atmospheric pressure.