NEIEP Mechanic Exam flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Rail plumb tolerance

Maximum allowable deviation of guide rail from vertical over the full hoistway height, set by the manufacturer and checked with a plumb line or laser; misalignment causes ride roughness and guide-shoe wear.

Counterweight balance percentage

Counterweight is typically sized as car weight plus about 45 percent of rated load, so the machine lifts roughly half the rated load in either direction and motor sizing stays balanced.

Rope equalization

Adjusting individual hoist rope tensions, using a dynamometer or deflection test, so all ropes share load equally; unequal tension overloads the tightest rope and shortens rope life.

Unlocking zone

The vertical zone, typically 18 inches (450 mm) above or below a landing, within which the landing door interlock may be released by a door-zone key or the car door operator.

Escalator step-to-skirt clearance

Gap between the step edge and the skirt panel, set per code after the truss is level and loaded; excessive clearance allows objects and shoes to be caught and creates a tripping hazard.

Machine beam alignment

Positioning the machine beam and traction sheave so ropes fall plumb to the car and counterweight hitches, checked with a straightedge and feeler gauge to avoid fleet-angle error.

Broken-wire rope retirement

A rope is retired when broken wires over a specified lay length, diameter reduction, corrosion, or valley breaks exceed the manufacturer's or code criteria, measured with a go/no-go gauge.

Brake holding test

Test confirming the brake stops and holds the car at rated load without excessive drift; checks lining thickness, drum condition, spring set, and coil gap before and after.

Governor trip test

Test that the governor trips at its set speed, applies the car safety to grip the rail, and that the governor rope and tension sheave move freely; results are recorded.

Door interlock function

Device that prevents the car from moving unless every landing door is closed and locked, and prevents a landing door from opening unless the car is at that landing within the unlocking zone.

Handrail speed check

Verification that the handrail moves at the same speed as the steps or slightly faster, within about 0 to +2 percent, so passengers are not pulled backward or forward.

Step chain elongation

Increase in step chain length from wear, measured against the manufacturer's limit; excessive elongation causes step synchronization error, noise, and possible chain skip on the sprocket.

Hydraulic rupture valve

Valve in the hydraulic cylinder line that closes if flow exceeds a set rate, stopping a free fall of the car if a pipe or fitting fails; checked during maintenance and testing.

Ohm's law

Relationship V = I x R, where voltage equals current times resistance; combined with P = V x I it lets a mechanic calculate expected current, voltage drop, and power in a circuit.

Three-phase power formula

Real power P equals the square root of three times line voltage times line current times power factor; used to size feeders, motors, and drives for three-phase elevator machines.

Synchronous speed

Speed of the rotating magnetic field in an AC motor, equal to 120 times frequency divided by number of poles; rotor speed is slightly lower by the slip.

Motor slip

Difference between synchronous speed and actual rotor speed, expressed as a fraction of synchronous speed; slip increases with load and is needed to produce torque in an induction motor.

VVVF drive

Variable voltage variable frequency drive that sets motor speed by output frequency and holds flux by adjusting voltage; used with encoder feedback for smooth, closed-loop elevator motion.

Normally closed contact

Relay or contactor contact that is closed when the coil is de-energized and opens when the coil energizes; used in safety circuits so a broken wire stops the machine.

Safety chain

Series loop of switches (governor, pit, top-of-car, final limits, door locks) wired so any open switch removes power from the driving machine; a fail-safe design.

Two-to-one roping

Rope arrangement where the rope travels twice the car travel distance; it halves the load on each rope part but doubles rope speed relative to the car.

Brake torque formula

Friction torque equals coefficient of friction times normal force times effective radius; brake capacity must exceed static load torque at rated load with margin, verified by test.

Starting torque versus voltage

In an AC induction motor at constant frequency, torque is proportional to the square of applied voltage, so reducing voltage to 70 percent leaves only about 49 percent of starting torque.

Lockout/tagout

Procedure to isolate the mainline disconnect, lock and tag it, then verify zero energy with a meter before work; only the person who applied the lock removes it.

Top-of-car inspection station

Control station on the car top with an inspection/normal switch and stop switch, used when riding the car top; the car must be on inspection and secured before entry.

Pit stop switch

Switch in the pit that removes power from the driving machine so a mechanic working in the pit can stop the car; required near the pit ladder for safe pit entry.

ASME A17.1 scope

Safety Code for Elevators and Escalators covering design, construction, installation, operation, testing, and maintenance requirements for new and altered equipment in the United States and Canada.

ASME A17.3 scope

Safety Code for Existing Elevators and Escalators, setting minimum retroactive safety requirements for equipment already installed, such as door restrictors and pit ladders.

Fall protection anchor

Full-body harness and lanyard attached to a rated anchor point, required when working at height or on a car top without a guardrail, to arrest a fall.

Hoistway opening barricade

Guardrail or barricade placed around open hoistway and floor openings to prevent falls by workers and the public; required whenever an opening is unattended.

Electrical CAT rating

Category rating of a test meter indicating the transient overvoltage level it can safely withstand; the meter must be rated for the circuit being tested, such as CAT III or IV.

Out-of-service tag

Tag placed on unsafe equipment to prevent use until the defect is corrected; the condition and required repair are documented and reported to the owner.