The motor of this rotary vane vacuum pump is totally enclosed and is cooled by the motor-cooling fan which directs air along the motor fins. The motors are fitted with a thermal overload device. When the motor is too hot, the thermal overload device switches off the pump. The thermal overload device has an automatic reset; when the motor cools down, the device resets and the motor will restart. An oil pressure system lubricates the pump shaft bearing surfaces and rotor sealing faces. The pump has an oil distribution valve which prevents discharge of oil to the pump interior (suck back) after the pump stops. The pumping chambers are air-tight, so this arrangement prevents oil suck back unless the gas ballast valve is open. You can inspect the level and condition of oil in the oil box reserv.
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