Question

Slip of reciprocating pump becomes negative when 
1. Theoretical discharge is more than actual discharge
2. Actual discharge is more than theoretical discharge
3. Theoretical discharge is equal to actual discharge
4. Pump is running at low speed

Answer 1

Correct Answer - Option 2 : Actual discharge is more than theoretical discharge

Reciprocating pump:

Reciprocating pump is a positive displacement pump where a certain volume of liquid is collected in an enclosed volume and is discharged using pressure to the required application.

Slip:

Slip of a pump is defined as the difference between the theoretical discharge and actual discharge of the pump. The actual discharge of a pump is less than the theoretical discharge due to leakage.

Mathematically,

slip = Qth- Qact

where,

Qth = Theoretical discharge

Qact = Actual discharge

Negative Slip:

Negative slip of a pump is defined as the difference between the actual discharge and theoretical discharge of the pump.

Mathematically,

Negative slip = Qact- Qth