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Elevator Mechanic Exam Review
A contractor wants to raise the car speed from 100fpm to 125fpm, it currently has a 12" sheave. What sheave is required? - Diam=12" 12/4=3" 25fpm=3" 100fpm + 25fpm= 12"+3"= 15" sheave A MOV (Metal Oxide Varistor) burns out. You replace it, but cannot read voltage or resistance. What should you do? - Replace it with a larger MOV On a Ward-Leonard circuit the break is set, but the motor is trying to slip through the break. What is the issue? - Suicide Circuit You have an old DC motor and are adding an SCR drive, what do you do to the interpoles? - Leave the interpoles alone. When adding a SCR drive to the generator, the series loop is removed, as are the 3 resistors. Everything else remains the same A hydro runs up with no load, but will not run with a full load. What is the issue? - The relief valve is set too low Runby for a 1:1 hits the CWT buffer 4" below the top landing. CWT runby should be set at 18". How much should the ropes be shortened? - 22" You need to work on a freight door retiring cam, you LOTO the main line but there is still power on the cam. What circuit is still hot? - Door Operator Disconnect/ Main Line Disconnect The contractor requests that the vertical center of a Rack and Pinion hoist be moved. How do you do this? - Adjust Tie Downs and Wall Ties Working pressure on a Hydro is 400psi. What is the maximum relief valve setting? - 400psi x 150%= 600psi What must be installed on a false car before operation? - Spring Loaded Safeties.
There is slight arcing between the brush and commutator. What action must be taken? - None. Heavy arcing=Light brush pressure. Heavy bush pressure=mechanical wear If rigging gear is roped 3:1 and a BEAM CLAMP is used to lift a 6,000lb load. What is the beam capacity? - 18,000lbs. Beam capacity is cut in half with use of clamp, when rigging all blocks, rope, and clamps will be Equal to the lowest load rating How much resistance is measured over a normally closed switch? - 1.2ohms. should be zero, but will never be that low A car traveling in the hoistway always stops at the same spot and blows a fuse. What causes this? - Traveling cable has a cut/exposed wire or a short How is a class 1 yearly buffer test preformed? - Car at bottom landing and on inspection, jump out direction and final limits. With pit clear, run down to compress buffers, buffers should fully extend within 90 seconds. 5yr: Full load Full speed CWT: Full speed Empty How many strain supports are required on a 350ft raceway? - 4. 1 every 100ft How is stainless steel drilled out? - Slow speed and constant pressure What is the required amount of retainer clips for wedge shackles and what is the spacing? - Minimum 2 clips. 1st at a maximum 4x the diameter of the rope 2nd at a maximum 8x the diameter above the 1st clip A 300ohm resistor burns out, but you don't have another one. How can you make one? - 2 600ohm resistors in parallel is 300ohms. Resistance is half of highest resistor in parallel circuit. 3 225ohm resistors in parallel is 75ohms.
How must Oxygen and Acetylene tanks be stored? - Vertically, 12 feet apart, or on a cart with a ½ hour fire barrier between them What is code for sill to sill distance? - Minimum ½ inch Maximum 1 ½ inches When drilling a jack hole in sandy conditions what type of drill rig is required? - Rotary or Auger bit. Rotary=Soft Percussion=Rocky Combo=Solid A customer does not want an escape hatch on a residential elevator, under what condition is this legal? - Manual operation must be provided Your helper wired the down direction and final limit switches, now the car will only travel up, what is the issue? - The down direction limit was wired incorrectly. What are the effects of one rope sitting deeper in the sheave groove? - The rope wears out and breaks faster There is a noise coming from a freight door. The sheave is moving, but the chain is not. What is the problem? - Oil on the drive chain What is the effect when you change a sling angle from 60 degrees to 30 degrees? - More tension, less capacity. Any angle 30 or less is dangerous How many points of a contact must be maintained on a ladder? How far above landing must it extend? What is proper Ratio? What steps don't we use? - 3 points of contact. 3 foot above. 4:1. Top 2 steps You open a dumbwaiter access panel and it still runs, what is the problem? - Pit access switch is not working properly You perform a static load test with the pit valve closed. The car sinks 6" in 15 minutes. What is the problem? - Cylinder leak
Where should you aim a fire extinguisher to put out a fire? - At the base of the fire Car with selective collective system is moving to the lobby to take a call, an up call is put in at the 2nd floor, what happens? - The call is bypassed until the car is traveling up During construction you land an escalator, but it is 10mm low, what is wrong? - The pit is too deep or column MARK is off During construction the Omega CWT rails have been damaged, what happened? - The Omegas were over tightened How do you handle a co-worker who shows up drunk? - Speak with MIC, Call BA, call supervisor How do you attach brackets to brick? - Inserts set back a ¼ inch into the block. Code could call for through bolts What is Selective Collective System? - Controller that allows an elevator to bypass calls in the opposite direction of travel. Generator runs at 600rpm and has 4 poles, what is the output frequency? - 20hz 600/60=10 10x2=20 RPM 60 x frequency / pole/ If a XOR gate was connected to a NOR gate and attached to an AND gate with a High output. What is input of the XOR gate A&B? - Both must be High Using BINARY logic, what DIP switches must be on for a 128 bit 30 second timer set at 150% - 1,3,4,6= seconds How many wires are needed for the following circuit? Exclude spares. BCE---SPI/BCD---SP2/BCD--- SP4/BCD---UR1/BCE---UR2/BCE---DR1/CRE--- DR2/GRD - 11 wires. You do not need the duplicates
A motor needs a sleeve bearing replaced, what type of bearing do you need? - Friction bearing AKA Sleeve bearing. Anti-Friction Bearing AKA Ball bearing 7 - foot platform with inside cab clearance of 6'8", what is the thickness of the cab walls? - 2 - inch-thick walls You notice Roughing on the Gov and Tail Sheave. What should you check? - Rope Diameter Car doors are dragging in the sill, how high should the car doors be above the sill? - ¼ inch What type of safeties are required on a 300fpm car? - Type B wedge clamp What stopping devices are required on vertical platforms? - 2 pan switches. 15lbs max pressure What type of oil is required for sleeve bearings? - Single viscosity SAE 20 What is the maximum inclination for moving walks? - 12 degrees How does a GFI work? - Detects an imbalance between Hot and Neutral Wires Who is required to provide MSDS or SDS for a solvent you are using? - Your employer How do emergency doors swing? - Outwards You have an EMT run with 3-90s, 2-45s, and a saddle bend. What is required? - An Intermediate pull box. 360 degrees is most bends for a continuous pipe What is the maximum distance between vertical race way supports? - 15 feet
What is the smallest wire used inside travelers and outside of travelers? - #20awg #24awg What is the maximum distance between strain relief supports? - 100 feet What is the maximum length Motor-Generator leads can be outside of a controller? - 6 feet In what section of NEC is elevator, escalator, moving walks, and dumbwaiters? - Article 620 What is the ratio between the loop and diameter of a round traveler? - 30 times What are the most common features of Load Weigh? - Control generator field and Inside express operation What is required by ASME on the car top? - Inspection station, Light, and Duplex outlet. At what distance from closed does the gate switch operate? - 2 inches What is the minimum number of spares that should be pulled? - 10 % At what speed should the Gov. switch contact be set to open? - Electrical 90% of Tripping speed for 150fpm-500fpm. 95% for +500fpm If the DC output of a 3 phase rectifier is lower than specified, what is the problem? - AC fuse is blown. 1 input phase is missing What is the overlap minimum on 2 & 3 speed doors? - Horizontal ½ inch Vertical 1 inch
What holds a stopped Hydraulic elevator? - Check valve What must be done if you get on top of a dumbwaiter? - Never fully get on top. Work only partially on with the mainline disconnect off How do you measure an escalator hand rail? - Mark the top and bottom of the inclination, measure in between and move the car until the bottom mark is at the top, measure again and continue doing this until you see your 1st mark. The last measurement will be shorter. Add all the measurements together to get your length. A moving walk has an inclination of 10degrees, what is the highest angle it can be? - 12degrees escalator 31degrees In a Ward-Leonard system, if all 3 contacts close what will happen? - The car will run at full speed What type of oil do you put in a machine? - Gear oil, non-detergent, single viscosity A 75ohm resistor has blown, no replacement, how do you fix it? - 3 - 225ohm resistors in parallel. 3 - 25ohm resistors in series If a Rack and Pinion hoist is not plumb, level and square. What can happen? - Set the Safeties What are extension tubes used for? - Necessary clearance for placement of concrete forms. If a hoist motor is making noise, what is the problem? - To help prevent distortion to the building AC supply, INDUCTORS can be used on AC input of a solid state drive. Inductors can serve double duty, they operate as Transformers, to match input voltage, or provide voltage isolation. As well as performing filtering on notch effect. What is the area of a 10" plunger? - Pie x Radius Squared= Area 3.14x5x5=78.
The escape hatch opens in what direction? - From the outside of the car up, preventing people from getting on top of the car What drawing will show how many and location of fixtures? - The elevator Abstract. Rails, lanterns, push buttons, etc. and quantity, color, material, etc You have to order P.I. for a 12 stop building with 3 cars. 3 floors do not have P.I. what is the total number of P.I. you need to order? - 12x3=36 total floors 3 floors with no p.i.= 36 - 9=27 P.I. needed If an elevator travels 1760rpm @ 60hz, how many hz needed to run at 600fpm? - 20hz 600/60= assume 4 poles. 10x2= You see a saw tooth wave form when using an oscilloscope out of the encoder, is that good? - NO. A perfect encoder will show a square wave. Saw tooth, when encoder has a fault What are the hand signals for crane operation? - Thumbs out=Boom out Thumbs in=Boom in Thumb up=Boom up Thumb down=Boom down Finger up clockwise=Hoist up Finger down counter clockwise=Hoist down Arm out=Stop You are working on a MOD and have to move the controller 30 feet farther away, you notice voltage drop, what can be done to increase voltage? - Use a larger gauge of wire What is the weight of normal rails? 15 full 16' rails and 2 8' rails - 16 x 16' x 15lbs = 3840lbs What is an acceptable substitute for the top rail of a barricade? - ¼ inch thick wire rope What is the proper way to test incoming voltage? - 3 phase AC using digital meter: L1-L2 L1-L3 L2-L Hydro at pump starter. Traction at L1, L2, L
You are preparing to replace a resistor on an out of service car. What is the 1st thing do? - Make sure it is LOTO and verify no voltage. What are 3 major factors in Hydraulic pit maintenance? - Oil, Tripping hazards, Electricity What is the tolerance for 3/8 at .003? - 372 -. bilateral=2 direction unilateral=1 direction You are installing push buttons using snake eye screws. What type of screwdriver? - Tamper Proof You are working with EYE BOLTS, where would you check for lifting capacity? - NEVER use eye bolts for hoisting You are installing the limit cam on the car and notice that the holes are not lining up. Where do you find the correct location for the cam? - The mechanical detail drawing You are on a call and find the pulley came off the pump motor and the set screw is missing, what kind of screw would you use to replace the set screw? - Cup Screw You have to measure the outside of a pipe. What tool would you use? - Caliper Rule You are installing spring buffers on a 200fpm car, what is the minimum buffer stroke? - 4inch 100fpm 1 ½ inch 100fpm-150fpm 2 ½ inch 200fpm 4 inch You are going to replace the disc on your grinder, what test should you do before using? - Ring test How often do electrical cords need to be checked for continuity? - Every 3 months The DBG is 6'6" using 15lb rails with ¼ shim on the brackets, what is DBB? - 7' 1 ½" 15lb rail is 3 ½ deep so 7" total.
2 ¼" shim is ½". 6'6" + 7 ½" =7 foot 1 ½ inch How does OSHA classify a competent person? - One who is capable of identifying existing and potential hazards, and who has authorization to take prompt, Corrective measurements Car weighs 7,000lbs with a capacity of 3,500lbs. what does the CWT weigh? - 8,400lbs 3500 x 40 / 100=1,400lbs 7,000 + 1,400 = 8, You are stacking rails in a single hydro hoist way, with a rise of 48' how many rails will you need? - 6 total rails 48' / 16' = 3 3 x 2 sides = 6 rails Installing a 3,000lb capacity car, how much load will the break stop and hold? - 3,750lbs 125% of rated capacity 3,000 x 125 = 375,000 / 100 = 3, On traction elevators where are the bottom guide shoes mounted? - To the safety plank You have a hoist rated at 3,000lbs, if you use a double block to single block reeving, what would your total lifting capacity be? - 6,000lbs You need to find the DBG for the car, where would you find this information? - Final layout or Hoistway plan view drawing You are hoisting rails into the hoist way using a capstan hoist, your apprentice is having a hard time pulling in rails. What can be done to make it easier? - Add another or more wraps to the capstan hoist Responding to a call on a hydro, you determine that the 50amp circuit breaker that feeds the controller has tripped. What component of the elevator has the ability to cause this problem? - The pump motor
Exciter voltage comes from what source? - Generator Your pulling 15 #14awg 27 #16awg 57 #18awg wires. How many spares needed? - 2 # 3 # 6 # 10% spares required You have 26 16' 22lb rails and 2 8' 22lb rails, what is the total weight of the rails? - 27 x 16 x 22 = 9504lbs You need to replace an unmarked SINGLE PHASE transformer with primary voltage at 220vac current at 5amp. What size would you need to double it? - KVa sizing must be calculated from primary or secondary volt + amp info Single phase kVa=(VxI) / 1,000 kVa=220x5=1100 / 1000= 1. kVa 2.2 kVa needed to double You have attempted to start up a 3 phase AC motor and stalls then hums or growls? - If the rotor bar becomes loose at the ring connection, or if the rotor bar cracks, current cannot flow through The bar and the entire rotor field is disrupted, causing loud growl or humming sound Your fluke digital Multimeter reads 440vac, what value are you reading? - 440vac RMS You have determined that the period of an oscillation that you can feel in the car is .5 seconds. What is the frequency of the oscillation? - 2hz Frequency from time or Period F=1/T F=1/.5= 2hz Customer complains that elevator is having door problem at every floor. Where do you start trouble shooting? - The car doors Freight doors are binding because they are hanging out of square, what adjustments can you make? - Adjust door track chains
You are about to start installing your duct run in the hoist way. What is the best method to give you the straightest line? - Using a plumb bob, snap the line, and measure off of the rail When installing multiple Traveling cables, where is the 1st cable located? - 1 st is closest to the rail. 2 controllers in a small machine room face each other, what is the minimum clearance between them? - 36 inches When installing travelers, what is the minimum length of vertical suspension at both ends before the loop starts? - 4 feet You attempt to adjust a new VV-VF door operator, but it operates in the wrong direction. How do you change the direction? - Change the phase sequence You receive a call that a center opening car is running with one door partially open, how is this possible?
- The gate switch is activated by the door drive, but the relating device has failed In order to properly bond an isolation platform, where should you connect your bonding straps? - From the platform to the car sling As a mechanic you are sent to install an escalator, what point of reference would you use to square the unit? - Column LINE Escalator demarcation lights are required by code for what reason? - To provide passengers with a visual indication when entering and exiting the unit. While adjusting a passenger elevator door operator with a PERMANENT MAGNENT DC motor. Which operation would you perform to control the motor? - Speed and Torque control is accomplished by varying armature current and voltage only SHUNT MOTORS: shunt voltage increases, torque increases, speed decrease. Shunt voltage decreased, torque decrease, speed increase Armature voltage increase, rotation speed increase affecting door speed and torque.
You find a blown fuse in the DC circuit feeding the door motor. When picking a replacement fuse what should you do? - Compare the blown fuse to the fuse rating in the straight line diagram A DC door motor supplied from a 3 phase rectifier runs slow. The DC voltage is normally 320 is 220. What should you do? - Check the fuse feeding the AC rectifier There is a call that a traction elevator is stuck in the overhead. In order to get the car down, what circuits do you need to jump out? - The primary safety circuits You just pulled multi-cables down the hoistway of a high rise. How should you provide strain relief for the cables? - Required every 100'. Begin installing at the lowest and work upwards to adjust and tension Installing Horizontal sliding doors with guides in each door panel, how far must each guide engage the sill gauge? - ¼ inch Your supervisor informs you to change software on a hydro microprocessor board. The software is a 24 pin DIP package. To properly orientate the new chip on the board, what must you do? - Verify that the notch on the dip chip matches the notch on the board You need to speed up an AC motor that has a fixed number of poles. How can you speed it up using the RPM formula? - Change the frequency. RPM= 60 x F / P/ You have finished digging a hole hydro, the jack is not on site. What must the hole have on it before you leave? - A welded cover A CWT frame weighs 10,000lbs and needs to be increased by 5%. What is the new weight of the frame? - 10,500lbs 10,000 x 5 / 100= 500lbs +10,000 = 10,500lbs You have 32' of rise in scaffolding and are using a 3'x5' base. Where are tie offs? - 1st at 12' and cannot be more than 26' apart vertically 30' apart horizontally
How is a step level switch on an escalator reset? - Manually What is the Law of Power? - P=ExI What is the maximum voltage drop that can occur across a 500watt resistor carrying 2amps of current? - 250 volts P/I 500/2= While testing for a locked rotor condition, what could happen if the testing was carried on for too long? - Damage to the stator or rotor What is needed to coordinate the movement and to dispatch hall calls? - A group controller Where is weight added on a freight door for balancing? - On the top. What door is heavier on bi-parting freight doors? - The lower door because of the tucking sill What happens to the break when contact E opens? - Inserts more break resistance in the circuit, reducing the value of the break current. More resistance to hold the coil up and release current draw. In a circuit with capacitance of 5mf 120v and 200K ohm, how long to fully charge? - 5TC .005 x 200 = 1(TC) 1 x 5 = 5 to fully charge. 1 time constant = 63.2% 5 time constant = 99% Valve Operations: - Check valve: oil flow in 1 direction Up valve: controls up start and accel to high speed, up slow down, up level, up stop Down valve: Elevator not running so it depends on system pressure Bypass and Relief: bypass oil if striking obstruction. If relief pressure is too low it will not pick
