Mechanics Exam ** An MOV burns out, you replace it but cannot read voltage or resistance. What should you do?CORRECT ANSWERReplace it with a larger one (630)
- On a Ward-Leonard circuit, the brake is set but the motor is trying to slip through the brake. What
circuit is the issue? CORRECT ANSWERSuicide circuit (425) ** A Hydro runs up with no load but does not run up with a full load. What is the issue? CORRECT ANSWERThe relief valve is set too low (805) ** Runby for a 1:1 car hits the CWT buffer 4" below the top landing. The CWT runby should be set at 18". How much should the ropes be shortened? CORRECT ANSWER22" for 1:1.
For a 2:1 with the same issue is 44".
** You need to work on a freight door retiring cam. You LOTO the mainline disconnect but there is still power to the cam. What circuit is still hot? CORRECT ANSWERMainline disconnect (535) ** The contractor requests that the vertical center of the Rack and Pinion hoist be moved. How is this accomplished? CORRECT ANSWERAdjust Tie downs/Wall ties (805) ** Working pressure on a Hydro is 400 PSI. What is the correct Relief Valve Setting? CORRECT ANSWER600 PSI Max. (805) 400 psi x 150% = 600 psi ** A contractor wants to raise the car speed from 100 FPM to 125 FPM. It currently has a 12" sheave.What size sheave is required? CORRECT ANSWER15" (125 /100 = 1.25 1.25 x 12 = 15) ** There is slight arcing at the Brushes and Commutator. What actions must be taken? CORRECT ANSWERNone. (430) 1 / 2
"Heavy arcing is due to light brush pressure. Mechanical wear indicates heavy brush pressure.** How much resistance is normally measured across a normally closed switch ? CORRECT ANSWER1.2 ohms or 1 to 2 ohms ** A car traveling in the hoistway always stops at the same point and blows a fuse. What is the problem? CORRECT ANSWERTraveling cable has a cut or short ** How is a Class 1 (yearly) buffer test performed? CORRECT ANSWERAt slow speed and the buffer must return in 90 seconds. (555) *(60 seconds is acceptable) (90 seconds is code)
- year test (Class 5) is car at rated load and speed. Buffer must return in 90 seconds. CWT at rated speed
and buffer must return in 90 seconds.** How many Strain Supports are required on a 350' raceway? CORRECT ANSWER4 One for every 100' ** How is Stainless steel drilled out? CORRECT ANSWERSlow speed and constant pressure (205) ** What are the required amount of clips for Wedge Shackles and what is their spacing? CORRECT ANSWERAt least 2, with the first being 4 times the diameter of the rope from the top of shackle.Second is 8 times the diameter of the rope from the first.** Car is loaded with 125% and sinks. Why? CORRECT ANSWERSlipped through the brake.** A 300 Ohm resistor burns out. You don't have a 300 Ohm resistor to replace it. What can you use to make up the resistor? CORRECT ANSWER2 600 Ohms resistors in Parallel. "The resistance is half of the highest rating in a parallel circuit.3, 225 Ohm resistors in parallel equal 75 Ohms.** A 480 VAC Step Down Transformer is connected to a 3 phase rectifier. What will the output be?
CORRECT ANSWER320 VDC
480 - 33.33% = 320
- / 2