The most important consideration when choosing a Variable Frequency Drive (VFD) is to know the type of load that is being applied to the motor because it will determine the size and cost of the VFD. The VFD must have sufficient current capability so that the motor can produce the required torque for the load.
How do I choose a VFD for my motor?
Thus, the rule of thumb for sizing the single phase input on a three-phase drive is to use a VFD rated for 2 times the FLA of the motor. For example if your motor is a 10 HP motor with a FLA of 28 amps, then you would need to select a VFD with an amp rating of 56 amps which ends up being around 20 HP.
What factors should be considered while selecting VFD for an application?
Read below to learn more about the six factors you should be considering when choosing a VFD.
- Full Load Amperage. The first step in this process is making sure the drive can handle the motors current demands. …
- Overload. …
- Application Type. …
- Altitude. …
- Temperature. …
- Carrier Frequency.
How do you tell if a motor is rated for a VFD?
Three major factors should be considered when determining if a motor is compatible with a VFD: the motor winding insulation, motor bearings and pump operating speed range.
Can I put a VFD on any motor?
Output voltages are available for VFDs to match almost any existing motor voltage. However, very few, if any, VFDs have a direct 13,800-volt output for very high-voltage motors. For these cases, using a step-up transformer on the output of the VFD is often necessary to match the motor voltage.
What are the types of VFD?
The main three types of VFD are VSI, CSI, and PWM.
- VSI type VFDs. VSI stands for Voltage-source inverter. This is the most common type of variable frequency driver. …
- CSI type VFDs. CSI stands for current source inverter. …
- PWM type VFDs. This is an improved and modified version of VSI type VFDs.
Can a VFD damage a motor?
VFDs can wreck motor windings.
VFDs control motors with a simulated sine wave known as pulse width modulation (PWM). The problem is that peak voltages created by the VFD can often get high enough to break through motor insulation and short out motor windings.
How is VFD load calculated?
- ((Synchronous Speed – Rated Full Load Speed) / (Synchronous Speed)) * 100% = Slip Rating.
- ((1800RPM-1750RPM) / 1800RPM) * 100%= (50RPM/ 1800RPM) * 100%
- (50RPM/ 1800RPM) * 100%= . 027 * 100%
- . 027 * 100% = 2.7%
- Slip Rating = 2.7%
How much can you overspeed a motor with a VFD?
Motors generally have to withstand 10 % overspeed. But it in no way means many motors cannot withstand much higher over speeds.
How long does a VFD last?
The Short Answer
Most manufacturers will admit the typical life expectancy is about 7-12 years … but there are many factors at play. VFD components like fans and capacitors have a finite life and starting at about 5 years, these components can start to fail and will need to be replaced.
Who makes the best VFD?
I know I need a VFD, but which manufacturer is best?
- Lenze AC Tech. These variable frequency drives are popular for their NEMA 4X indoor and outdoor vfd options. …
- Fuji Electric. Known for their high-quality FRENIC series of variable frequency drives. …
- Delta Industrial Automation. Delta drives are available from ¼ to 475hp in 115 to 575V. …
- GE Industrial Solutions.
What is constant torque?
Constant torque loads require the same amount of torque at low speeds as at high speeds. Torque remains constant throughout the speed range, and the horsepower increases and decreases in direct proportion to the speed. … With constant torque loads, the torque is not a function of speed.
How do you know if a motor is inverter duty?
Motor insulation systems that are rated for inverter use will be specified on the motor nameplate (or a sticker). These systems should have wire rated for a minimum of 1600 volt spikes, F or H class insulation, and will be processed with 100% sold resin in a vacuum pressure impregnation (VPI) system.
Can you put a VFD on any 3 phase motor?
It is not advisable to operate a single motor with a variable frequency drive. While it is technically possible, the disadvantages far outweigh any benefits that you might expect. In a majority of cases, it is less expensive to upgrade to a 3 phase motor for use with a VFD.
When would you use a VFD?
So, energy savings, intelligent motor control and reduction of peak-current drawn are three great reasons to choose a VFD as the controller in every motor-driven system. The most common uses of a VFD are for control of fans, pumps and compressors, and these applications account for 75% of all drives operating globally.