Buying the perfect fit for your VFD application can be quite confusing considering the many variables attached to every system and your application. Below are certain suggestions and tips that will make your buying task less daunting and enable you to obtain the right fit.
Know Your Requirements
Before you go into the process of buying it is essential to gather data about your motor system. This pertains to the horsepower, voltage, service factor, RPM, full load amps (FLA) and whether the motor is inverter duty rated or not. Other data pertains to the requirements of your application like what are the speed range required, whether variable torque or constant torque is needed and any other specific enclosure needs. Once you have all this data at your end, comparing the features of various drives to decide the perfect fit becomes much easier.
Use the Collected Data Rightly
You can start to shortlist your selection by first understanding the horsepower of the load as other variables can be used for sizing the VFDs further on. Next the comparison of your motor’s FLA and VFD’s amp ratings will help you to reduce the shortlist still further. It is always wise to purchase a VFD with a slightly greater amp rating initially as that proves beneficial in the long run with regards to the functionality and reliability. Ascertaining the type of load required by your application is important. If centrifugal driven equipment is involved like a pump or a fan then variable torque drive is suitable as that will give maximum energy savings. If the application requires constant torque levels for all speeds like in case of conveyors, punch presses, positive displacement pumps then VFD dealers will assure you that constant torque variable frequency drives are more suitable.
It is necessary to ensure that the motor is not run at speeds lesser than 20% of the stated maximum allowable speed. At the same time the motor should not be run at speeds exceeding 20% of the rated speed. Get to know from the motor manufacturer the allowable speed range of your motor.
The control method involved in your application also decides the type of VFD to be purchased. Under the 2 wire control a single switch is involved to run the drive while under a 3-wire control two switches are needed to run the drive. An industrial application on a process or conveyor control will opt for the two switch drive while HVAC applications opt for a one switch drive.
Special enclosure needs refer to the environment in which the drive operates and this aspect too forms an important consideration in the selection process. As far as voltage is concerned it is essential to match the motor and VFD voltage with the voltage available on the site. Variable Frequency drive dealers will advise you on this aspect or send one specialist from their end to ascertain your needs perfectly.
Another component that forms the foundation of all electric motor system is the geared motors; more information on this can be obtained from gear dealers including inline helical gear dealers.