Interpretation on the Working System, Quota and Rated Value of Electric Motors
1、 Work system
1. The definition of work system: It indicates a series of load conditions that the motor is subjected to, including starting, no-load, stopping, and energy interruption, as well as their duration and sequence.
Among them, no-load refers to the rotating state of the motor with zero power output.
Full load: refers to the state in which the motor operates at its rated capacity.
Shutdown and power-off: Refers to the state where the motor is in a state of no motion and no electrical or mechanical energy input.
2. The types of work systems: Work systems can be divided into several types: continuous, short-term, periodic, or non periodic.
Periodic work system includes one or more constant loads with a specified duration, and the motor does not reach thermal stability during load operation; The load and speed in non periodic work systems usually vary within the allowable operating range. The codes for work schedules are generally represented by S1~S10. Below are a few types of work schedules that we commonly use.
3. S1 working system: continuous working system; Keep running at a constant load until it reaches thermal stability.
4. S2 working system: short-term working system; Running at a constant load for a given period of time, if the motor does not reach thermal stability within that time, it will shut down and cut off energy, and the time will be sufficient for the motor to cool down again.
After S2, the duration of the work schedule should be marked, with priority given to 10, 30, 60, or 90 minutes.
5. S3 working system: intermittent cycle working system; Operate according to a series of identical work cycles, each cycle including a period of constant load operation time and a period of shutdown and power-off time, and the motor does not reach thermal stability during load operation.
After S3, the load duration rate tP/(tP+tR) should be marked
2、 Quota and rated value
1. Quota refers to a set of rated values and operating conditions.
The categories of quotas include: continuous work quota corresponding to S1 work system
The short-term work schedule corresponds to the S2 work system
The set amount of periodic work corresponds to the S3~S8 work system
The non periodic work schedule corresponds to the S9 work system
The work schedule for discrete constant load corresponds to the S10 work schedule
2. Rated value refers to various numerical values that characterize the normal operating state of a motor, such as power, voltage, current, frequency, speed, etc. that we see on the nameplate, all of which are called rated values. (Can you briefly introduce the regulations and calculations for frequency, voltage, speed, etc.)
3. Operating conditions
Site conditions: (1) Altitude not exceeding 1000m
(2) The maximum ambient air temperature shall not exceed 40 degrees Celsius
(3) The minimum ambient air temperature is greater than minus 15 degrees Celsius
(4) The water temperature of the cooling medium should be greater than 5 degrees and less than 25 degrees
Electrical conditions: (5) The power supply meets the standard requirements
(6) The waveform of voltage and current requires symmetry
(7) The voltage variation during operation is less than ± 5%, and the frequency variation is less than ± 1%
