Three Factors Determine The Motor Power

 

Three Factors Determine the Motor Power:

 

1) The heating and temperature rise of the motor are the most important factors determining the motor power;

2) Allow short-term overload capacity;

3) For asynchronous squirrel cage motors, starting capacity must also be considered.

 

 

First, the specific production machinery calculates and selects the load power according to the heating, temperature rise and load requirements of the Xi'an Simo motor, and the motor pre-selects the rated motor power according to the load power, working system and overload requirements. After the rated power of the motor is pre-selected, the heating, overload capacity and starting capacity verification when necessary are also required.

 

If one of the items is unqualified, the motor must be reselected and rechecked until all items are qualified. Therefore, the duty system is also one of the necessary requirements. If there is no requirement, the most common S1 duty system will be used by default; motors with overload requirements also need to provide overload multiples and corresponding running time; when asynchronous squirrel cage motors drive large inertia loads such as fans, the load's inertia and starting resistance torque curves are also required to verify the starting capacity.

 

The above selection of rated power is based on the standard ambient temperature of 40℃. If the ambient temperature of the motor changes, the rated power of the motor must be corrected. According to theoretical calculations and practice, when the ambient temperature is different, the motor power can be roughly increased or decreased according to the following table.

 

Therefore, the ambient temperature also needs to be provided in areas with harsh climates. For example, in India, the ambient temperature needs to be calibrated at 50°C. In addition, high altitude will also affect the motor power. The higher the altitude, the greater the motor temperature rise and the smaller the output power. And the motor used at high altitude also needs to consider the impact of corona phenomenon.

 

 

Regarding the motor power range of motors currently on the market, here are some data for your reference.

 

DC motor: ZD9350 (grinding machine) 9350kW

Asynchronous motor: squirrel cage type YGF1120-4 (blast furnace fan) 28000kW

Wound type YRKK1000-6 (raw mill) 7400kW

Synchronous motor: TWS36000-4 (blast furnace fan) 36000kW (test unit reaches 40000kW)

 

Rated voltage of the motor

The rated voltage of Xi'an Simo motor refers to the line voltage under rated working mode.

The selection of the rated voltage of the motor depends on the power supply voltage of the power system to the enterprise and the size of the motor capacity.

The selection of AC motor voltage level mainly depends on the power supply voltage level of the place of use. Generally, the low voltage network is 380V, so the rated voltage is 380V (Y or △ connection), 220/380V (△/Y connection), 380/660V (△/Y connection). When the power of low-voltage motor increases to a certain level (such as 300KW/380V), the current is limited by the bearing capacity of the wire and it is difficult to increase, or the cost is too high.

 

It is necessary to increase the voltage to achieve high power output. The high-voltage power grid supply voltage is generally 6000V or 10000V, and there are also 3300V, 6600V and 11000V voltage levels abroad. The advantages of high-voltage motors are high power and strong impact resistance; the disadvantages are large inertia, and it is difficult to start and brake.

 

The rated voltage of the DC motor should also match the power supply voltage. Generally, it is 110V, 220V and 440V. Among them, 220V is the commonly used voltage level, and high-power motors can be increased to 600~1000V. When the AC power supply is 380V and powered by a three-phase bridge thyristor rectifier circuit, the rated voltage of the DC motor should be 440V. When powered by a three-phase half-wave thyristor rectifier power supply, the rated voltage of the DC motor should be 220V.