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.
Do you need a special motor 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. … The manufacturer should be consulted directly for determining the winding insulation of a specific motor.
Can a VFD damage a motor?
Shaft currents induced by VFDs can lead to motor failures. Without some form of mitigation, shaft currents travel to ground through bearings, causing pitting, fusion craters, fluting, excessive bearing noise, eventual bearing failure, and subsequent motor failure. This is not a small problem.
Can you put a VFD on a 2 speed motor?
It is doable to set up a VFD to work with the 2 speed motor and switch motor connections and VFD settings using a rotary switch. … VFDs do work with older motors, but you are usually limit in the variable speed range that the motor will maintain constant torque and I would not run it above the base speed.
How do you select a VFD for a motor?
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.
26 февр. 2018 г.
How much can you overspeed a motor with a VFD?
With the use of Variable Frequency Drives (VFD), motors can be run at higher than 60 Hz, known as an overspeed condition, typically as direct drive fan wall/plenum fans (per NIH DRM 6.2. 4.2, the maximum operating speed is 90 Hz).
Does a VFD replace a motor starter?
VFD does essentially replace a motor starter in applications where they are used, there still can be control schemes where a contactor may be used to interrupt power – typically only for occasional shut down situations and not as a routine control method – VFD’s don’t play well with contactors in the circuit, total …
Can VFD causing motor vibration?
Understanding Motor Bearing Currents
Circulating bearing currents—related to the use of VFDs—are primarily caused by the speed of the inverter switching in the output stage of a VFD. … When the fluting becomes severe enough, bearings can fail, which causes increased motor vibration.
What motors are compatible with VFD?
If the Motor is pre-EPAct (1992), it should be run on VFDs only with careful consideration. Motors made during that time were not made for VFD use, but if they are VFD rated, will be okay. Class F insulation or higher is suitable for VFD use, but VFDs may have no more than a 2:1 Constant Torque ratio.
How does 2 speed electric motor work?
Two Speed, Two Winding
The two winding motor is made in such a manner that it is really two motors wound into one stator. One winding, when energized, gives one of the speeds. When the second winding is energized, the motor takes on the speed that is determined by the second winding.
How does a Dahlander motor work?
A Dahlander motor achieves different speeds by switching the configuration of the electrical windings, indirectly adding or removing poles and thus varying the rotor speed. The poles can be varied at a ratio of 1:2 and thus the speed can be varied at 2:1.
Can you oversize a VFD?
An oversized VFD can be used for a smaller HP motor. The advantage of this application is that if the motor requirements increase, the VFD may be large enough to still handle the increased load.
How many motors can a VFD control?
With one VFD per motor, each motor can be controlled separately and run at a different speed. This is not so when running multiple motors from one VFD. Second, running multiple motors from one VFD creates a single point of failure.
Why we use VFD for motor?
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.