A drive system for a fluid displacement pump includes an electric motor, a drive coupled to the rotor at a first end of the electric motor, a fluid displacement member mechanically coupled to the drive, and a pump frame mechanically coupled to the electric motor. The electric motor includes a stator and a rotor disposed on an axis. The drive coupled to the rotor converts the rotational output to a linear, reciprocating input to the fluid displacement member. The rotor is disposed about the stator to rotate about the stator.

A system having a material sensor system coupled to a material tank is provided. The material tank is configured to receive a quantity of the material and output a flow of the material. The material sensor system includes a float system coupled to an inner surface of the material tank. The float system includes a float configured float within a float cavity. The material sensor system includes a switch coupled to an outer surface of the material tank. The switch is communicatively coupled to the float system through a wall of the material tank, and the switch is configured to send one or more signals to a control system when the float engages the switch.

The present invention relates to a compressor device (1) comprising: a compressor installation (2) having at least one compressor element (3a, 3b, 3c) for compressing a suctioned gas, the compressor element (3a, 3b, 3c) being driven by an electric motor (4); a heat recuperation system (6) for recuperating heat from a compressed gas resulting from the compression of the suctioned gas, the heat recuperation system (6) comprising a piping network (7) having an inlet (8) and an outlet (9) for a coolant, said piping network (7) being provided at this inlet (8) or outlet (9) with control means with a flow rate control state variable for modifying a first flow rate of the coolant in the piping network (7); and a control unit (13) which adjusts the flow rate control state variable of the control means on the basis of a drive current of the electric motor (4) or on the basis of a second flow rate of the suctioned gas such that a temperature T.sub.w,out at the outlet (9) of the piping network (7) is driven to a predefined level.

A control system may include circuitry configured to: a deterioration level estimation unit configured to estimate deterioration levels of pumping devices based on information about driving forces of the pumping devices; a selection unit configured to select a pumping device from the pumping devices based on a comparison of the estimated deterioration levels estimated by the deterioration level estimation unit; and a pumping control unit configured to control the selected pumping device selected by the selection unit to pump fluid.

A current value determination device provided with: a capacitor current computation unit for computing the capacitor current of a capacitor included in a high-voltage circuit that drives a motor, on the basis of the input voltage of an inverter included in the high-voltage circuit and the revolution speed of the motor; and a capacitor current determination unit for determining the value of capacitor current on the basis of the input voltage of the inverter, the revolution speed of the motor, the capacitor current computed by the capacitor current computation unit, and a prescribed model for determination.

Even when abnormal heat generation occurs during operation in a state where the temperature of a compressor is not increased, abnormality cannot be detected. A fluid machine includes a fluid machine body; a motor that drives the fluid machine body; a temperature sensor that measures a temperature of the fluid machine body; and a control unit that controls the fluid machine body. The control unit changes a temperature threshold value based on at least one of a pressure of a fluid discharged by the fluid machine body and a frequency of a voltage input into the motor, and issues a notification when the temperature of the compressor body measured by the temperature sensor exceeds the temperature threshold value.

A motor leakage current detector and/or a heat compensating circuit, devices using same and related methods are disclosed herein. Included are a uniquely wired current transformer to allow for polarity agnostic leakage current detection, a leakage current detector using same and having a notifier to alert a user. In other forms, an accessory power cord and power strip are disclosed capable of detecting early motor failure conditions. In still other forms, other machinery failure early warning systems are disclosed as are numerous motor operated devices using same including without limitation pumps.

A refrigeration apparatus includes a compressor connected to a refrigerant circuit, and a bearing monitor. The compressor includes a compression mechanism, an electric motor, a drive shaft, and a plain bearing that supports a journal portion of the drive shaft. The bearing monitor performs an abnormal-state operation to cope with poor lubrication on the plain bearing if an abnormal state condition is satisfied. The abnormal state condition is a condition indicating that a rate of change of current exceeds a first reference value. The rate of change of current is an amount of change in a driving current usable to drive the compressor per unit time. The journal portion of the drive shaft has a surface roughness of at least 0.05 μm.

An oil lubricated compressor having a universal motor, efficient starting and re-starting characteristics, and a long operating life. The oil lubricated compressor can have a brushed or brushless universal motor which can drive a cooling fan and a pump. The universal motor can achieve a high torque to voltage ratio, as well as a high torque to current ratio, upon starting or re-starting of the compressor. Optionally, the oil lubricated compressor can use a single cooling fan disposed in the compressor at a location which is between the universal motor and a cylinder head of the pump.

The present disclosure provides a control method of a compressor and a refrigerant circulation system. The control method includes deciding whether a current working volume state of the compressor is matched with a control instruction after the compressor completes a change to a working volume according to the control instruction, determining that the compressor operates normally in a case where the current working volume state of the compressor is matched with the control instruction, and determining that the compressor operates in fault in a case where the current working volume state of the compressor is not matched with the control instruction.