# Technology Support

### MOTOR TERMINOLOGY

Rating
Rating is specification of the operating limit of motor, including motor's output power, voltage, current, frequency, torque and rpm, etc. In terms of temperature rise, there are two types, continuous rating and short period rating.
Synchronous RPM
Motor frequency and poles can decide motor rpm. Reference formula is as follows:
Ns = ( 120 x f ) / P
Ns：Synchronous rpm (rpm)
120：Constant
f：Frequency
P：Poles
Rated Torque
The torque at rated rpm is the rated torque.

Continuous Rating and Short-Period Rating
Continuous rating refers to continuous operation of the motor under rated output; short-period rating refers to motor running at rated output within a specified period of time.
Output Power
Indicated the power that can be performed by a motor within a unit time. The power performed by the motor is determined by rpm and torque. Reference formula is as below:
Output (Kw) = ( T x N ) / 97400
T：Torque (Kg.cm)
N：RPM
1HP：0.746Kw
Starting Torque
The torque is produced instantly when motor is started. The motor will not start in case a load is larger than such a torque.
Slip
One of the methods to indicate rpm, reference formula as below:
S = ( Ns - N ) / Ns
S：Slip
Ns：Synchronous rpm ### SELECTION OF MOTOR

01
General Introduction of Speed Reducer Series Calculation of Reduction Gear Ratio
Customers choose the most appropriate reduction gear ratio according to their requirement to match output rpm of gear reducer with the rpm of operating machines. (AAC)
i = Nm / Ng or 1 / i = Ng / Nm
i：Gear ratio
Ng：Output Speed of gear reducer (rpm)
Nm：Motor running speed (rpm)

02
Torque Calculation Formula of Direct Link Speed Reducer
Customer choose the most appropriate model to suit the machine's output torque of the speed reducer. (Constant torque)
Tg = Tm x i x η
Tg：Reducer output torque
Tm：Motor output torque
i：Ratio
η：Speed reducer transmission efficiency