ELECTRICAL TEST Part A - Technical
What color wiring is used for the following:
1. AC Control circult 150 volts or less
2. Voltages over 150 volts
3. DC Control Circuit 150 volts or less
4. Wire is not de-energized when disconnect is off
5. Equipment grounding (non-current carrying)
6. Grounded Circuit (current carrying)
7. What is the difference between THHN vs. MTW wire?
8. What is the purpose of a diode placed in parallel to relay?
9. What does CRM stand for?
10. What does PLC stand for?

The power source in a certain welding setup generates 3500w that is transferred to the low carbon steel work with a heat transfer factor of 0.85. the melting factor in the operation is 0.45. a continuous fillet weld is to be made with a cross-sectional area of 23 mm2 determine the travel speed at which the welding can be accomplished.

Acommercial grade cubical freezer, 4 m on a side, has a composite wall consisting of an exterior sheet of 5.0-mm thick plain carbon steel (kst= 60.5 w/m k), an intermediate layer of 100-mm thick polyurethane insulation (kins 0.02 w/m k), and an inner sheet of 5.0- mm thick aluminium alloy (kal polyurethane insulation and both metallic sheets are each characterized by a thermal contact resistance of r 2.5 x 104 m2 k/w. (a) what is the steady-state cooling load that must be maintained by the refrigerator under conditions for which the outer and inner surface temperatures are 25°c and -5°c, respectively? (b) for power saving purpose, which wall material should be increased/reduced in. thickness in order to reduce 50% of the cooling load found in part (a)? redesign the thickness of the proposed material. 177 w/m-k). adhesive interfaces between the q=575.93 w

A75mm diameter shaft is supported in a journal bearing 75mm long with a diametral clearance of 0. 1mm. it supports a radial load of 1000 n and is lubricated with sae 50 oil at 70°c. find the friction torque and the power loss when the crankshaft rotates at 2900 rev/min.