Electric pump and fluid supply apparatus

A fluid supply apparatus comprising:

• a first pump which pumps fluid from a fluid reservoir;
• a first supply passage for conveying pumped fluid to a destination of the fluid to be supplied;
• a relief valve provided on the first supply passage, the relief valve preventing an increase of fluid pressure in the first supply passage to be equal to or greater than a predetermined pressure;
• an intake port which pumps fluid from either the fluid reservoir or a separately provided fluid reservoir;
• an electric driven second pump having a discharge port for discharging pumped fluid;
• a second supply passage merged with the first supply passage between the first pump and the relief valve;
• a rotor provided on the second pump and electrically driven by a brushless sensorless motor;
• and
• a mechanism for preventing losing synchronism of the brushless sensorless motor by controlling hydraulic pressure in the discharge port not to exceed a predetermined pressure value lower than operational pressure of the relief valve.