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How does Hz affect motor speed?
V/Hz control maintains a constant ratio between voltage (V) and frequency (Hz). Varying the voltage frequency affects both the motor speed and the strength of the magnetic field. When the frequency is increased (for higher motor speed), the magnetic field decreases, and lower torque is produced.
How does a VFD work on a fan?
A VFD is a motor controller that can adjust the motor speed and thereby change the fan speed. This allows the fan user to adjust airflow by either decreasing or increasing the motor’s speed.
What kind of control would you use on a VFD to maintain temperature with a fan?
For a VFD-equipped supply fan, the fan speed can be modulated to maintain the space temperature set point, whereas the cooling and heating coil valves are used to control the supply air temperature (SAT).
Can you put a VFD on a belt drive fan?
VFD on belt drive is no problem. in fact, the softstart of a VFD will save many belts.
Can you have a VFD on a belt drive fan?
Is VFD and VSD same?
A variable frequency drive (VFD) refers to AC drives only and a variable speed drive (VSD) refers to either AC Drives or DC Drives. VFDs vary the speed of an AC motor by varying the frequency to the motor. VSDs referring to DC motors vary the speed by varying the voltage to the motor.
Is it OK to use a Low Speed VFD fan?
The low speed of a VFD is there to use. The thermal capability of the fan to cool is limited by the low speed. Install an appropriately rated fan or blower and the motor will be OK. By the way the V/F should take care of the lower frequency.
What happens when the frequency of a VFD increases?
When a VFD increases frequency above 60 hertz, HP and torque do a complete flip flop. HP remains at 100 percent, and torque decreases as frequency increases. The torque reduction occurs because motor impedance increases with increasing frequency.
Can a TEFC motor run a Low Speed VFD?
The fan on a TEFC motor will be turning too slowly to provide any significant cooling capacity for the heat generated. This is not new nor does it apply only to AC VFD. DC motors which can have high torque and low speeds and also wound rotor motors have the same limitations. The low speed of a VFD is there to use.
How does a VFD affect horsepower and torque?
How a Variable Frequency Drive or VFD relates to horsepower and torque. My January 2013 Pumps & Systems’ column focused on the reduction in motor horsepower (HP) as frequency is reduced by a variable frequency drive (VFD).