跳至主要内容

Interpretation of the standard of motor working system

1. Interpretation of the standard of motor working system
The operating system of the motor indicates the permissible cycle time of the motor under different loads.The classification of the working system of the motor is the description of the load bearing condition of the motor, which includes the starting, electric braking, no-load, break-energy stopping and the duration and sequence of these stages. Iec60034-1 divides the working system into 10 categories.
(1) continuous operation, S1.Continuous running S1 is an operation with constant load that lasts long enough to achieve thermal equilibrium.
(2) short run, S2.A short run is a run with a load that is too short to achieve thermal balance.The interval (no voltage applied on the motor) is very long, which has actually reduced the motor temperature to the temperature of the cooling medium. The recommended duration of short operation is 10min, 30min, 60min and 90min.
(3) start intermittent operation with no influence on temperature, S3.Intermittent running of S3 involves running a continuous sequence with the same time interval.Each interval includes a zone constant load time and an interval time.These times, neither load time nor cooling time, are sufficient to achieve thermal equilibrium within the time interval, and it is assumed that the peak current at startup has no significant effect on heating.
(4) start intermittent operation with influence on temperature, S4.Intermittent operation S4 involves operations consisting of continuous sequences with the same time interval.Each interval includes a starting time, a time with constant load, and an interval time.
These times are not enough to achieve thermal balance within this time interval. In this operation, the motor either stops naturally after power failure or is stopped by mechanical brakes, so the windings hardly generate additional heating.
(5) intermittent operation with influence on temperature by starting and braking, S5.Intermittent running of S5 involves a continuous sequence of operations with the same time interval.Each interval includes starting time, time with constant load, braking time and intermittent time.None of this time is enough to achieve thermal equilibrium in that interval.In this operation, braking is achieved by electricity (e.g. reverse current).
(6) continuous operation with discontinuous load, S6.Continuous running S6 involves running a continuous sequence with the same time interval.Each interval includes time with constant load and idling time.These times, either at load or at cooling, are insufficient to achieve thermal equilibrium within that interval.
(7) uninterrupted operation with starting and braking, S7.Running S7 uninterrupted involves running a sequence of consecutive sequences with the same time interval.Each interval includes a starting time, a time with constant load, and an electric braking time (for example through a reverse current).None of this time is enough to achieve thermal equilibrium in that interval.This operation does not stop, the motor is actually always under the action of the voltage.
(8) continuous operation with variable speed, S8.An uninterrupted run of S8 involves a run consisting of a continuous sequence with the same time interval.Each interval includes a constant load time with one of its velocities and a constant load time with other velocities directly connected to it.Pole - changing asynchronous motor is an example of this mode of operation.
(9) duty system S9 with aperiodic changes in load and speed.The load and speed of the system vary aperiodic within the permissible range, including frequent overloads, which can exceed the base load by a wide margin.
(10)Discrete constant load and rotational speed working system S10.The duty system consists of a specific number of discrete loads (or equivalent loads)/speeds (if possible) and each combination of loads/speeds should last long enough to achieve thermal stability of the motor.The minimum load value in a working cycle can be zero (no load or stop and break).

2, some other provisions on the work system
In addition to the corresponding code S1~S10 as a symbol, the work system type shall also meet the following requirements:
● for S2 working system, the working time should be added after S2.
● S3 and S6 work schedule shall be followed by load duration rate.For example, s2-60min, s3-25%, s6-40%.
● for S4 and S5 working system, load duration rate, motor's moment of inertia and load's moment of inertia should be added after the code number.
● for S7 working system, the moment of inertia of the motor and the load should be added after the code number to calculate the value of the motor shaft.
● for S10 duty system, the nominal value of corresponding load and its duration should be marked after the code.


评论

发表评论

此博客中的热门博文

The general tests of electric motors：2

2. Determination of dc resistance of winding: 1) Significance of dc resistance measurement: The dc resistance of the windings in cold state is one of the main parameters of three-phase asynchronous motors. By comparing the measured value of the resistance of the windings with the design value, it is possible to check whether the windings have broken wires and short-circuit between turns, whether the welding parts have virtual welding or open welding, whether the contact points have bad contact and other phenomena. 2) Dc resistance measurement method: Measuring the dc resistance of the motor should be done when the winding is cold. First, place the motor indoors for a period of time, and measure the temperature of the motor winding end or core with a thermometer. At this time, the measured temperature is the actual temperature of the winding in the cold state. If the temperature of the winding end or core cannot be measured, the temperature of the housing may be substituted
发表评论
阅读全文

Comparison of structure motor with internal rotor and external rotor

In general, the stator of the motor is on the outside and the rotor is on the inside. In a conventional brush dc motor, the stator field is on the outside and the rotor armature is on the inside. Brushless dc motor appeared, so that the rotating armature from the inside to the outside, from the rotor into a stator; And the original stationary stator permanent magnet went inside, and from the stator become the rotor. This kind of structure is called an "internal rotor structure". In practical use, sometimes in order to meet the special technical requirements of some electromechanical, the motor stator armature is made inside, and the rotor with permanent magnet is made outside. We call this structure "external rotor structure", or "internal stator structure". In the design of brushless dc motor, the external rotor structure and the internal rotor structure have their own advantages and disadvantages. The differences in motor characteristics between the
发表评论
阅读全文

Traction motor for electric vehicle： induction motor, permanent magnet motor, who is the future direction?

In the era of fuel cars, we often hear the battle between natural inspirations and turbocharged engines. And in the era of electric cars, there is also a clear debate between electric motors. After the test of the market, there are two kinds of mainstream electric motors on the market at present, one is induction motor (also known as asynchronous ac motor), the other is permanent magnet motor. Induction motor is a kind of motor which has the rotor rotation powered by magnetic torque created by the physical interaction of stator winding magentic field and the induction current generated rotor magnetic field. Tesla Model S and Model X are representatives of induction motor applications. The permanent magnet motor mainly refers to the permanent magnet synchronous motor, and the biggest difference with the induction motor in structure is that the rotor is permanent magnet structure, rather than wound by the electric coil. Which is better, the induction motor or the permanent mag
发表评论
阅读全文