YZR 、 YZ Series Lifting And Metallurgical Applications

The YZR and YZ series three-phase asynchronous motors are specialized motors designed for various types of metallurgical, lifting machinery and other similar equipment. They feature high overload capacity and mechanical strength, and are suitable for frequent starting, braking and equipment with significant vibration and shock under short-time or intermittent periodic duty. The power ratings and installation dimensions of the motors comply with the IEC recommended standards and are similar to the Japanese JEM1202 and German DIN42681 standards, with most being interchangeable. The motors can operate normally at an altitude not exceeding 1000 meters. The insulation classes of the motors are divided into F and H grades: F grade is suitable for general locations where the ambient air temperature does not exceed 40°C; H grade is suitable for metallurgical locations where the ambient air temperature does not exceed 60°C. Both types of motors have the same parameters. The protection class for general locations is IP44, and for metallurgical locations, it is IP54.

The rated frequency of the motors is 50Hz and the rated voltage is 380V. The YZR series are wound rotor motors, conforming to the JB/T10105-1999 standard, while the YZ series are squirrel cage rotor motors, conforming to the JB/T10104-1999 standard.

(1) Electric motors are suitable for intermittent periodic operation. Depending on the nature of the load, the operating regimes of electric motors are classified as follows:

1.Short-time operation (S2): The motor operates at a constant load for a given period of time and then stops and is de-energized for a period of time to cool down to within 2K of the ambient temperature.

2.Intermittent periodic operation (S3): The motor operates in a series of identical operating cycles, each consisting of a period of constant load operation and a period of stoppage and de-energization, both of which are too short to allow the motor to reach a thermal steady state, and the starting current of each cycle has no significant effect on the temperature rise.

3.Intermittent periodic operation including starting (S4): The motor operates in a series of identical operating cycles, each consisting of a starting period, a period of constant load operation, and a period of stoppage and de-energization, all of which are too short to allow the motor to reach a thermal steady state.

4.Intermittent periodic operation including electric braking (S5): The motor operates in a series of identical operating cycles, each consisting of a starting period, a period of constant load operation, a period of rapid electric braking, and a period of stoppage and de-energization, all of which are too short to allow the motor to reach a thermal steady state.

5.When selecting an electric motor, all starting and braking conditions should be converted into equivalent starting times per hour, and the motor rating should be determined based on this equivalent starting time. Examples of conversion are shown in the table below.

6.Conversion methods:

(1) If the motor speed at the end of a point start does not exceed 25% of the rated speed, four point starts are equivalent to one starting.

(2) One electric braking (braking to 1/3 of the rated speed) is equivalent to 0.8 starts.

(3) The reference operating regime of the motor is S3-40%, and the data for the delivery state is given on the motor nameplate. If the user does not specify the operating regime, only the data for the reference operating regime is given on the motor nameplate. When the motor needs to operate under an operating regime other than S2-S5, it should be negotiated with the manufacturer.