Assignment & Tutorials

Batch 1: CO2 - BTL 4

Hydrostatic transmission operating at 70 bar pressure has the following

characteristic for the pump and the motor:

Pump :

Capacity of pump, CP = 82 cm3/ rev ( pump displacement)

Volumetric efficiency of pump, ηVP = 82 %

Mechanical efficiency of pump, ηMP = 88 %

Speed of pump , N = 500 rev / min

Motor:

Capacity of motor, CM = ?

Volumetric efficiency of motor, ηVM = 92 %

Mechanical efficiency of motor, ηMM = 90 %

Desired speed of motor , N = 400 rev / min

Estimate the value of Actual Torque, Ta = ?

Batch 2: CO2 - BTL 4

A pump supplies oil at 20 gpm to a 2-in. diameter double acting hydraulic cylinder. If the load is 1000 lb 9extending and retracting) and the rod diameter is 1 in., evaluate

• hydraulic pressure during the extending stroke

• piston velocity during the extending stroke

• cylinder horsepower during the extending stroke

• piston velocity during the retraction stroke

• Cylinder horsepower during the retraction stroke.

Batch 3: CO1 - BTL 5

A transfer machine with 11 stations has an ideal cycle time of 36 seconds. The frequency of line stops is 0.085 stops per cycle. When a line stop occurs, the average downtime is 5.5 minutes.

Determine (a) average production rate in parts per hour, (b) line efficiency, and (c) proportion downtime.

Batch 3: CO2 - BTL 4

Design a Fail safe circuit for a Hydraulic press with consideration towards operator safety. Analyze the circuit proposed.

Assignment 2

Tutorial 1

Question 1: A transfer machine with 12 stations has an ideal cycle time of 39 seconds. The frequency of line stops is 0.085 stops per cycle. When a line stop occurs, the average downtime is 5.5 minutes. Determine (a) average production rate in parts per hour, (b) line efficiency, and (c) proportion downtime.

Question 2: A transfer line with 34 stations has an ideal cycle time of 0.65 minutes, an average downtime of 8.6 minutes per line stop occurrence, and a station failure frequency of 0.02 for all stations. After analysis, the system designer proposes to locate a storage buffer between stations 27 and 28 to improve line efficiency. Determine, first, the current line efficiency and production rate. Secondly, the maximum possible line efficiency and production rate that would result from installing the proposed storage buffer.