The main purpose of a variable frequency drive is to control the speed of electric motors in Lethbridge with precision. This makes it possible for motor speeds to be increased and decreased while the connected load is maintained at the desired speed and the energy consumed is minimized. For those who are looking to extend the lifespan of the equipment and reduce the cost of maintaining electric motors in Lethbridge, here are some of the main benefits of a variable frequency drive.
Reduced Starting Current
When you start AC electric motors in Lethbridge, using power drawn directly from the line, it may use up to 7 to 8 times the motor’s full load current to startup both the motor and the connected load. This huge current will flex the windings of the motor and produce so much heat that it can drastically reduce the lifespan of the electric motor. But when a VFD starts up a motor with zero voltage and frequency, the voltage and frequency build up gradually and magnetizes the motor windings. This usually requires just a maximum of 70 percent of the full load current. Invariably, this will extend the motor life.
Fewer Power Line Fluctuations or Surges
When you start an AC motor directly from line current, the demand for 600 percent of the motor’s maximum load current puts a huge drain on the main power distribution system. When the supply voltage drops, depending on the motor’s size and the total capacity of the distribution system, the voltage drop will make other sensitive equipment on the same connection trip off. This equipment includes sensors, computers, contactors and proximity switches. Using a variable frequency drive will prevent this common voltage drop because the motor starts at zero voltage and then gets ramped up gradually.
Lower Power Demand at Startup
Power is proportional to the product of voltage and current. This means that the amount of power required to start up an AC motor directly from the line voltage is much higher than what is required with a VFD. The major challenge here is that many distribution systems across the world are at their limit at certain times called “peak hours”. At this time, industrial consumers who start their electric motors will be charged for surges in power consumption. But this can easily be eliminated by using a VFD.
Variable torque loads, like pump loads and centrifugal fans that are operated using a variable frequency drive will cut down energy consumption. These components have a variable torque load such that horsepower is proportional to the cube of speed and torque. So if the speed of the fan is reduced by half, the horsepower required to run the fan is reduced a cube of half which is one-eighth. This means that if a VFD is controlling a motor connected to a pump which runs at less than full speed the energy consumption will be significantly lower than what will be consumed by a motor running at full speed during the same time interval.
Those are some of the main reasons why you need to install and maintain variable-frequency drives when you use electric motors in Lethbridge. A VFD saves a lot of energy, prolongs motor lifespan, and makes motor control more intelligent.