Q1. Advantages of super long stroke??

Advantages of super long stroke1. Super long stroke means increased swept volume allowing more mass of air to be drawn into the cylinder which in turn allows more fuel to be burnt, hence increasing power output

2. Super long stroke increases piston travel time and thereby decreases crank speed so more time for combustion during the stroke.

3. The efficiency of Large diameter propellers is best at slower RPM...With super long stroke we can have slower RPM of engine with no change in mean piston speed of the engine

4. Low grade fuels can be used

5.  Lower horizontal space consumed by cross head reduction of weight for same power.

6. More time for heat dissipation to cooling water.

**FROM MAN B&W-- The slower running engines offer the use of larger propeller diameters with the associated improved efficiency improvement. According to MAN Diesel & Turbo for the propulsion of tankers and bulk carriers, there is the possibility of adapting the design of the after part of the hull to accommodate even larger propellers thereby requiring engines of even lower speeds. Current estimates suggest that running the new designs offer potential fuel savings between four and seven per cent with a similar reduction in CO2 emissions.

Disadvantage- increased lateral force on guides due to the relatively short connecting rods

Q2) Welding transformer rating??

TECHNICAL SPECIFICATION

Model ARMAC AC AXP-350 AXP-450 AXP-600

1. Welding Current range AMPS. 30-350 A 30-450 A 40-500A

2. Max. Cont. current at 60% Duty

Cycle

AMPS. 350 A 450 A 600 A

3. Max. Cont. current at 100% Duty

Cycle

AMPS. 180 A 240 A 360 A

4. Open Circuit Voltage VOLTS 65 V 70 V 80 V

5. KVA Rating at 60% Duty Cycle KVA 19.5 26 32.5

6. Input supply VOLTS 2 Lines of 3 Phase

7. Frequency HZ 50HZ 50HZ 50HZ

8. Cooling Type Forced Air Cooled

9. Insulation CLASS H H H

10. Type of output Current

Regulation

MODE STEPLESS REGULATION