A thick steel slab (rho = 7800 kg/m3 , c = 480 J/kg·K, k = 50 W/m·K) is initially at 300°C and is cooled by water jets imping
ing on one of its surfaces. The temperature of the water is 25°C, and the jets maintain an extremely large, approximately uniform convection coefficient at the surface. Assuming that the surface is maintained at the temperature of the water throughout the cooling, how long will it take for the temperature to reach 50°C at a distance of 25 mm from the surface?
1 answer:
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Answer:
1) a. Customers requiring AC electric power transmission for powering remote devices which may include a subsea transmission system where power is distributed to subsea devices
b. Customers that utilize commutator-type motors
2) The primary voltage is 150 volts
Explanation:
The parameters given are;
Number of primary winding, = 50 turns
Number of secondary winding, = 150 turns
Voltage in secondary winding, = 450 volts
Voltage in primary winding =
The relation between ,
,
and
is as follows;
Which gives;
From which we have;
The primary voltage = 150 volts.