Obsessed time (or) selected time Rating Allowance = 120% = 10% As we know that, normal time = Observed time x Rating % 100 120 = 1.00 1.20 min 100 Allowance @ 10% 10 = 1.20 X 100 = 0.12 min Standard time = Normal time + Allowances = 1.20 + 0.12 = 1.32 min. . x12 - -: An operator manufactures 50 jobs in 6 hours and 30 minutes. If this time includes the time for setting his machine. Calculate the operator's efficiency. Standard time allowed for the job was: Setting time = 35 min Production time per piece = 8 min As standard time = Set up time + Time per piece x No. of pieces produced Standard time for manufacturing 50 jobs = 35+ 8 x 50 = 435 min 7 hours and 15 min. Standard time x 100 Efficiency of operator = Actual time 435 x 100 = 111.5%. 390 ILLUSTRATION 3: Following datas were obtained by a work study. Man from a study conducted by hours. (1) Maintenance time (a) Get out and put away tools = 12.0 min/day (b) Cleaning of machine = 5,0 min/day (c) Oiling of machine = 5.0 min/day (d) Replenish coolant supply = 3.0 min/day (i) Interruption (a) Interruption by foreman = 5.0 min/day (b) Interruption by porter etc. = 4.0 min/day (i) Delay time due to power failure etc. = 6.0 min/day (iv) Personal time 20.0 min day Calculate total allowances, total available cycle time productive hours, considering a working day of 8 hours