For a turbulent flow, frictional resistance is: 1. William Froude stated the following laws of fluid fraction under turbulent flow. Motor design is the primary influencer of rotational losses, and although theyвЂ™re not easily controlledВ by the user, itвЂ™s important to understand these losses, as they have a significantВ impact on motor efficiency. attributes to loss of energy which is commonly known as loss due friction or frictional loss. Common examples are short-circuit currents during commutation and flux distortion due to armature reaction. Losses that cannot be easily accounted for are generally lumped into the вЂњstray loadвЂќ category. Note that brush losses are sometimes included in the category of stray load losses. Neglecting frictional and other losses, and using the density of water as 1000 kg/m3, the mass flow rate of the waterjet (rounded off to two decimal places) in kg/min is.

The diameter of orifice of the nozzle through which the waterjet comes out is 0.25 mm.

The magnitude of brush losses depends on the voltage drop at the contact point and on the armature current. In a waterjet machining process, the water pressure used is 500 MPa. Brush lossesДuring commutation, some losses occur between the commutator and the brushes. For both the field and the armature, copper losses are equal to the square of current times the resistance of the currentвЂ™s path. These losses can be referred to by many names, including the term вЂњI 2R losses,вЂќ since theyвЂ™re caused by the resistance of the field and armature windings. Copper losses (aka electrical losses or winding losses) Magnetic losses are constant if the field current and speed are constant. Magnetic losses include hysteresis losses, caused by the changing polarity of the flux in the core, and eddy currents, which are induced in the steel core by the changes in flux polarity. These losses are associated with magnetic paths of the motor. Magnetic losses (aka core losses or iron losses) Mechanical losses increase with motor speed, but if speed is constant, these losses can be assumed to be constant. These include the friction in the motor bearings, friction between the brushes and the commutator, and drag on the rotor caused by turbulence of the air around it (sometimes referred to as windage loss). Mechanical lossesДЄs their name suggests, mechanical losses are caused by movement of the motor. Various types of losses, including rotational losses, reduce motor efficiency. Determine the flow direction and calculate the friction factor. At point A, elevation 40 m, a Bourdon gauge fitted to the pipe records 1.75 bar, while at point B, elevation 34 m and 1.5 km along the pipe a similar gauge reads 2.1 bar. (Note that in generators, mechanical power is converted to electrical power, but the losses experienced are the same.) While there are several ways in which manufacturers and experts group losses, one common methodВ is to divide them into five categories: mechanical, magnetic, copper, brush, and stray losses.Д«ecause mechanial losses and magnetic losses are approximately proportional to the motorвЂ™s rotational speed, they are often takenВ together and referred to as rotational losses. Head loss due to friction dynamic head EXAMPLE SHEET, Q2 A 0.75 m diameter pipe carries 0.6 cumec. DC motors, like all machines, experience some losses when converting electrical power to mechanical power.

No frictional loss pipesim