Table of Contents
Negative slip: When the theoretical discharge is less than actual discharge is known as negative slip.
What is meant by negative slip?
Slip of reciprocating pump: Slip of a pumps defined as the difference between the theoretical discharge and actual discharge of the pump. Negative slip occurs when delivery pipe is short, suction pipe is long and pump is running at high speed.
What is negative slip when does it occur?
Negative slip will occur when suction pipe is long, delivery pipe is short and pump is running at high speed.
When the slip of an induction machine is negative it is running as a?
When slip of an induction machine is negative, it is running as a generator.
What is slip in induction motor?
“Slip” in an AC induction motor is defined as: As the speed of the rotor drops below the stator speed, or synchronous speed, the rotation rate of the magnetic field in the rotor increases, inducing more current in the rotor’s windings and creating more torque. Slip is required to produce torque.
Why is negative slip?
Conditions of “Negative slip”: Due to High speed. Due to short delivery pipe. Due to long suction pipe.
What is slip formula?
If the revolving magnetic flux’s synchronous speed & the speed of rotor are Ns & Nr in the motor, then the speed among them can be equivalent to (Ns – Nr). So, slip can be determined as. S = (Ns – Nr) / Ns.
What is the slip?
Slip is the differentiation between synchronous and asynchronous speed. The difference between the synchronous speed of the electric motor magnetic field, and the shaft rotating speed is slip – measured in RPM or frequency. Slip increases with increasing load – providing a greater torque.
What is the difference between actual discharge and theoretical discharge?
The difference between the actual discharge and theoretical discharge is called a negative slip. When the theoretical discharge is less than actual discharge is known as a negative slip.
What is slip in pump?
Slip is the loss of pumping capacity due to fluid leaking back through a pump from the discharge side to the inlet side. It can affect the efficiency of all types of pumps although the actual causes may be very different.
What is the effect of negative slip in 3 phase induction motor?
Slip = 1, means that rotor is stationary. Negative value of slip in induction motor can be achieved when the rotor speed is more than the synchronously rotating magnetic flux. This is only possible, when the rotor is rotated in the direction of rotating magnetic flux by some prime mover.
What is synchronous speed?
The synchronous speed is the speed of the revolution of the magnetic field in the stator winding of the motor. It is the speed at which the electromotive force is produced by the alternating machine. The Synchronous Speed is given by the relation shown below.
What is the material of slip rings in an induction machine?
A wound rotor motor uses three slip rings, typically made of high-quality phosphor bronze, mounted on the shaft with brushes resting on them. Each slip ring is connected to one of the three phases of rotor windings.
What is the slip speed?
The speed at which the induction motor work is known as the slip speed. The difference between the synchronous speed and the actual speed of the rotor is known as the slip speed. In other words, the slip speed shows the relative speed of the rotor concerning the speed of the field.
What is full load slip?
The slip corresponding to full load speed of th motor is called full load slip. Example 1 : A 4 pole, 3 phase induction motor is supplied from Hz supply. Determine its synchronous speed. On full load, its speed is observed to be 1410 r.p.m. calculate its full load slip.
What causes motor slip?
Slip depends on motor parameters The traditional way to control wound-rotor-induction-motor speed is to increase slip by adding resistance in the rotor circuit. The slip of low-hp motors is higher than that of high-hp motors because rotor-winding resistance is greater in smaller motors.
What is positive slip?
A positive slip indicates that the wheels are spinning; negative slip indicates that they are skidding.
Which pump has high volumetric capacity?
Positive-displacement pumps are capable of developing high pressures while operating at low suction pressures. They are commonly referred to as constant-volume pumps. Unlike centrifugal pumps, their capacity is not affected by the pressure against which they operate.
What is percentage slip in reciprocating pump?
The percentage slip in a reciprocating pump set is given by the % of (where, Q₁ = actual discharge Q₂ = theoretical discharge) A.
What is the formula for slip speed?
Slip speed is the speed difference between the Synchronous speed and Rotor speed. Slip speed = Synchronous speed – Rotor speed = Ns -N. Slip, s = (Ns – N) / Ns.
How is slip of Ship calculated?
Calculate the value of the propeller slip during this period. ( A nautical mile equals 1852 m.) Soln: Slip (percent) = Engine distance – ship’s distance/ Engine’s distance X 100. Engine distance = Pitch X RPM X 60 X 24 / 1852.
What is meant by slip power?
What is meant by slip power? The portion of air gap power, which is not converted into mechanical power, is. called slip power. Slip power is nothing but multiplication of slip (s) and air gap.
Why do you conduct slip test?
Explanation: Slip test is used to determine the q-axis reactance. Explanation: The impedance during slip test is low so the voltage drop will be less and the current will be more. Explanation: Slip test is conducted at low terminal voltage to avoid large slip in the synchronous machines.
What is the importance of slip?
Slip creates a relative speed between the RMF and rotor. That keeps a torque continuously acting on it when the motor is running. So what would happen if slip becomes zero? Bcoz there will be no relative speed between RMF and rotor, and which will stop inducing rotor current.
How do slip rings work?
HOW DOES A SLIP RING WORK? A slip ring passes electrical signals and power across a rotating interface using sliding electrical contacts. These contacts are typically a rotating ring and a stationary brush, or wiper, that slides along the ring surface during rotation.
