Motors and Drives

Question 1

A motor is a __ __ device

Answer 1

Load driven

Question 2

Motor rating refers to the __ __ __, not the electrical input

Answer 2

Maximum mechanical rating

Question 3

refers to the actual load on a motor compared to its maximum capacity load
HP of mechanical load over HP of motor drive

Answer 3

Load Factor

Question 4

What is usually not on a name plate

Answer 4

NLRPM - no load RPM

Question 5

Name Plate info:

HP

Answer 5

capacity

Question 6

Volts

Answer 6

design input voltage - line to line

Question 7

motor’s speed

Answer 7

RPM

Question 8

Sped is dependent on what?

Answer 8

Number of pole pairs (between strator and rotor)

Question 9

Speed =

Answer 9

60 cycles/second * 60 seconds/ minute
Number of Pole Pairs
In RPM

Question 10

Energy efficient is __ % more efficient that standard efficienc
Premium efficiency is __ % more than energy efficienct
Super premium efficient is __% more efficient than premium efficienct

Answer 10

4-5%
2-3%
1-3%

Question 11

__ __ reduces motor efficiency

Answer 11

Voltage imbalance

Question 12

What size motors are more efficient?

Answer 12

large

Question 13

__ refers to the fact that an observer riding on the rotating stator field would see the rotor ___ backward

Answer 13

Slip, slipping

Question 14

__ __ = (NLRPM - FLRPM)

Answer 14

design slip

Question 15

NLRPM - Measured RPM

Answer 15

True slip

Question 16

__ __ = measured slip / design slip

aka NLRPM - Measured RPM / NLRPM - FLRPM

Answer 16

% load

Question 17

= Design HP (off nameplate) * % load (load factor)

Answer 17

Actual Load

Question 18

kW mechanical =

Answer 18

= HP * .746kW / hp * load factor

n (efficiency

Question 19

In motor savings math problems, you typically want to solve for

Answer 19

kW costs and and