What is a unit with a variable frequency?
The engine speed is used to control the variable frequency on the AC. Although it is more expensive in the first cost than a fixed speed engine, this type of system can provide cost savings by reducing public service expenditure and increasing the service life of the device. Power units with variable frequency systems change the engine voltage and frequency to increase or reduce pump flow. The result is an alternating current of a similar nature to AC supplied by usefulness, but with the ability to increase and reduce voltage and frequency. When connected to the pump, the engine drive engine can provide a variable frequency control without the use of control valve systems. It is ineffective to lower the pump at one speed and reduce flow flows. These systems are used in widea range of industries. Some chemical processes have narrow acceptable temperature limits for product quality. Different product flows can provide faster temperature settings than changing heat or cooling source.
water cooling towers have a high variability of water flow for the cooling of the process. During colder weather, less water flow is required and the system with variable speed can maintain the desired temperatures at much lower costs. Engine control with regulatory organs of the system temperature allows increasing water flow necessary for cooling.
Another advantage of variable speed motors is the ability to start. Start the motors connected to a constant voltague quickly and there are voltages on the engine with sudden pressure changes. Starting the engine with a frequency variable allows the motor to slowly increase the speed and there is a lower voltage. Less stress canlead to longer life life and reduce costs.
Most electric motors are cooled with fans connected to the engine drivers. One of the disadvantages of variable frequency drive systems is the loss of the fan cooling at lower speeds. This type of system can also cause further heating of the engine winding. In a warm climate, installation of engine temperature sensors or auxiliary fans may be required to prevent the engine overheating.
frequency variable motors can have a higher noise level than a constant speed engine. The frequency has a slightly different form of alternating wool than AC supplied by the tool. This can cause vibration of the engine winding, resulting in noise that can increase with lower motor frequencies and speeds.