Evaluation of motor
How to evaluate a motor? Typically industrial products can be evaluated with the following aspects. The most
important characteristic of industrial products is low deviation. 
(1) Full dimensions
The fundamental characteristics that customers require are assembling dimensions and outline dimensions. The
dimensional deviation of a good product should meet product standard requirement. (GB standard, industrial
standard or enterprise standard)
(2) Basic performance
a. Rated voltage: known parameter (unit: V) b. No load current: I0 (unit: A)  c. No load speed: n0 (unit: rpm)
d. Rated current: IL (unit: A)               e. Rated torque: TL (Unit: g.cm) f. Rated speed: NL (Unit: rpm)
g. Current in stall: Ist (unit: A)             h. Torque in stall: Tst (unit: g.cm)
i. Other parameters such as efficiency, power, electric potential constant, torque constant etc. can be calculated
from the above data. 
(3) Special characteristics
a. Vibration: amplitude (unit: mm), vibration velocity (unit: mm/s), vibration acceleration (unit: mm/s2)
b. Noise: sound pressure LP (unit: dB(A) and acoustical power LW (unit: dB(A). They are both relative values. 
c. EMC: This index is to evaluate the ability of the motor resisting the radio interference or the radio interference
level that the motor generates.
d. Environment test: This is to judge the load capability of the motor under high and low temperature. Alternating
temperature test is the common test. Alternating temperature and humidity test is more severe test. Magnetic field
of ferrite magnet decreases by 5-7% under -80 ℃. The motor electric performance is therefore deviated.
Mechanical shock, external alternating magnetic field, aging (long time) storage will also weaken the magnetic
field. 
e. Others: such as safety clearance, safety creepage distance, protection class, type of cooling etc.