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How to choose a right VFD according to your application ?

According to the load characteristics, we divide the application into constant torque applications and non-constant torque applications.What is a constant torque application? What is a non-constant torque application? I will explain it carefully .

Constant torque occasions: Fan pump, HVAC, conveyor , textile winding.As the name suggests, the load in constant torque is the torque characteristic that the load has been relatively constant or has little change during operation. The most obvious feature of this type of device is that the current fluctuations are small or no fluctuations in a short time.

For example,when we use the VFD for clean water pumps such as irrigation pumps, fire control pumps, water treatment pumps, etc. Since the liquid density in the pump is constant during operation of this type of pump, the current of the motor is substantially constant. This type of load does not require high performance of theVFD, and often only requires basic PID functions. I recommend that you use a pump-specific VFD. For example, Delta’s CP2000 series ,MS300 series, E series are perfect for these functions. Relatively high performance versions of these types of VFD are not only perfect for the functions required in these applications, but also economic. If we can solve our coustomer’s needs with less cost, this is the service that Zhangjiagang Haina Automation Equipment Co., Ltd. will provide to customers.

when It is used in the textile industry such as spinning frame, roving frame, winder, yarn doubling machine, etc. Although these types of equipment have little change in torque during operation, textile equipment requires quickly motor acceleration capability. If the motor starts for a long time, the yarn produced will not meet the production standard until the motor reaches the target speed. This type of equipment is characterized by constant torque, but it also requires the iVFD to have a certain torque change during use. These devices require a very powerful starting torque for the motor, which requires the Specialized optimization software of the VFD to do this. The starting curve of the fan pump type and the HVAC professional type VFD cannot achieve the application effect in these occasions. These applications usually require a high-performance version of the VFD, such as Delta’s C2000 and CH2000 series.

Non-constant torque occasions: pulverizer, mud pump, steel drawing equipment, elevator lifting industry

The current of this type of equipment varies greatly during operation. As we all know. The current magnitude is an important indicator of motor torque. In the rated voltage state, if the running current of the motor is large, the torque of the motor will be correspondingly large. If the current of the device changes greatly, this will be a rigorous test for the VFD. A motor that does not operate at a constant torque requires the VFD to have considerable compensation capability.In this case, we recommend that the customer select a four-quadrant frequency converter (“What is a four-quadrant VFD”). The Delta C2000 is the ideal solution to this problem. Delta C2000 series inverters not only have advanced four-quadrant operation functions, but also optimize the software, which is very suitable for occasions with variable loads.

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