NEIEP Mechanics Verified Multiple Choice and
Conceptual Actual Emended Exam Questions
With Reviewed 100% Correct Detailed Answers
Guaranteed Pass!!Current Update
Q1: What is the formula to calculate synchronous motor speed (RPM)?
ANSWER
RPM = (120 × Frequency) ÷ Number of Poles
You are modernizing a geared elevator system. The new 4-pole motor will run at
60 Hz. According to the print, the desired car speed is 350 FPM. What should the
sheave size be to meet this speed if the motor connects directly to the sheave at
synchronous speed?
ANSWER
RPM = (120 × 60) ÷ 4 = 1,800 RPM
Car speed = (π × D × RPM) ÷ 12 →
350 = (π × D × 1800) ÷ 12
D = (350 × 12) ÷ (π × 1800) = 0.743 inches (Not practical—requires gearing or 2:1
roping)
Q2: A geared traction elevator has a 15:1 gear ratio and uses a 24" sheave. The
motor runs at 1,800 RPM. What is the car speed (1:1 roping)?
ANSWER
Sheave RPM = 1800 ÷ 15 = 120 RPM
Speed = (π × 24 × 120) ÷ 12 = 753.98 FPM
,Q2: A 3-phase motor runs on 60 Hz power and has 4 poles. What is its
synchronous speed?
ANSWER
(120 × 60) ÷ 4 = 1,800 RPM
Q3: A motor has 6 poles and operates on 30 Hz power. What is the synchronous
speed?
ANSWER
(120 × 30) ÷ 6 = 600 RPM
Q4: A 2-pole motor connected to a 50 Hz supply will rotate at what speed?
ANSWER
(120 × 50) ÷ 2 = 3,000 RPM
Q5: If a 10-pole motor runs at 720 RPM, what frequency is the supply?
ANSWER
F = (RPM × Poles) ÷ 120 → (720 × 10) ÷ 120 = 60 Hz
Q6: A 6-pole motor is operating at 1,150 RPM. What is its slip if synchronous
speed is 1,200 RPM?
ANSWER
Slip = (Ns − Nr) ÷ Ns × 100 = (1,200 − 1,150) ÷ 1,200 × 100 = 4.17%
Q7: What’s the difference between synchronous and actual speed in an
induction motor?
ANSWER
, Synchronous speed is the theoretical maximum, while actual speed is slightly
lower due to slip.
Q8: A 3-phase elevator hoist motor is rated at 1,200 RPM. If slip is 3%, what is
the actual running speed?
ANSWER
1,200 × (1 − 0.03) = 1,164 RPM
Q9: Why does a motor with more poles rotate slower at a given frequency?
ANSWER
Because each cycle energizes more windings, increasing magnetic field rotation
time.
Q10: What is the RPM of a 6-pole motor on 60 Hz with 5% slip?
ANSWER
Synchronous speed = (120 × 60) ÷ 6 = 1,200 RPM
Running speed = 1,200 × (1 − 0.05) = 1,140 RPM
Q11: How do variable frequency drives (VFDs) control motor RPM?
ANSWER
By adjusting the input frequency, which directly changes RPM via the RPM
formula.
A car currently runs at 100 feet per minute (FPM) with a 12" drive sheave. If the
contractor wants to increase the speed to 125 FPM, what size sheave is required?
ANSWER
= 12 / X → X = 15" sheave
Conceptual Actual Emended Exam Questions
With Reviewed 100% Correct Detailed Answers
Guaranteed Pass!!Current Update
Q1: What is the formula to calculate synchronous motor speed (RPM)?
ANSWER
RPM = (120 × Frequency) ÷ Number of Poles
You are modernizing a geared elevator system. The new 4-pole motor will run at
60 Hz. According to the print, the desired car speed is 350 FPM. What should the
sheave size be to meet this speed if the motor connects directly to the sheave at
synchronous speed?
ANSWER
RPM = (120 × 60) ÷ 4 = 1,800 RPM
Car speed = (π × D × RPM) ÷ 12 →
350 = (π × D × 1800) ÷ 12
D = (350 × 12) ÷ (π × 1800) = 0.743 inches (Not practical—requires gearing or 2:1
roping)
Q2: A geared traction elevator has a 15:1 gear ratio and uses a 24" sheave. The
motor runs at 1,800 RPM. What is the car speed (1:1 roping)?
ANSWER
Sheave RPM = 1800 ÷ 15 = 120 RPM
Speed = (π × 24 × 120) ÷ 12 = 753.98 FPM
,Q2: A 3-phase motor runs on 60 Hz power and has 4 poles. What is its
synchronous speed?
ANSWER
(120 × 60) ÷ 4 = 1,800 RPM
Q3: A motor has 6 poles and operates on 30 Hz power. What is the synchronous
speed?
ANSWER
(120 × 30) ÷ 6 = 600 RPM
Q4: A 2-pole motor connected to a 50 Hz supply will rotate at what speed?
ANSWER
(120 × 50) ÷ 2 = 3,000 RPM
Q5: If a 10-pole motor runs at 720 RPM, what frequency is the supply?
ANSWER
F = (RPM × Poles) ÷ 120 → (720 × 10) ÷ 120 = 60 Hz
Q6: A 6-pole motor is operating at 1,150 RPM. What is its slip if synchronous
speed is 1,200 RPM?
ANSWER
Slip = (Ns − Nr) ÷ Ns × 100 = (1,200 − 1,150) ÷ 1,200 × 100 = 4.17%
Q7: What’s the difference between synchronous and actual speed in an
induction motor?
ANSWER
, Synchronous speed is the theoretical maximum, while actual speed is slightly
lower due to slip.
Q8: A 3-phase elevator hoist motor is rated at 1,200 RPM. If slip is 3%, what is
the actual running speed?
ANSWER
1,200 × (1 − 0.03) = 1,164 RPM
Q9: Why does a motor with more poles rotate slower at a given frequency?
ANSWER
Because each cycle energizes more windings, increasing magnetic field rotation
time.
Q10: What is the RPM of a 6-pole motor on 60 Hz with 5% slip?
ANSWER
Synchronous speed = (120 × 60) ÷ 6 = 1,200 RPM
Running speed = 1,200 × (1 − 0.05) = 1,140 RPM
Q11: How do variable frequency drives (VFDs) control motor RPM?
ANSWER
By adjusting the input frequency, which directly changes RPM via the RPM
formula.
A car currently runs at 100 feet per minute (FPM) with a 12" drive sheave. If the
contractor wants to increase the speed to 125 FPM, what size sheave is required?
ANSWER
= 12 / X → X = 15" sheave
