Today the VFD could very well be the most common kind of output or load for a control program. As applications become more complicated the VFD has the ability to control the velocity of the electric motor, the direction the motor shaft can be turning, the torque the engine provides to a load and any other engine parameter which can be sensed. These VFDs are also available in smaller sized sizes that are cost-effective and take up less space.
The arrival of advanced microprocessors has allowed the VFD works as an exceptionally versatile device that not only controls the speed of the engine, but protects against overcurrent during ramp-up and ramp-down conditions. Newer VFDs provide ways of braking, power increase during ramp-up, and a number of handles during ramp-down. The biggest financial savings that the VFD provides is usually that it can make sure that the motor doesn’t pull extreme current when it starts, so the overall demand factor for the whole factory can be controlled to keep the domestic bill as low as possible. This feature only can provide payback more than the cost of the VFD in under one year after purchase. It is essential to keep in mind that with a normal motor starter, they’ll draw locked-rotor amperage (LRA) when they are starting. When the locked-rotor amperage takes place across many motors in a manufacturing facility, it pushes the electrical demand as well high which often outcomes in the plant paying a penalty for every one of the electricity consumed through the billing period. Since the penalty may become as much as 15% to 25%, the cost savings on a $30,000/month electric bill can be used to justify the purchase VFDs for practically every motor in the plant even if the application might not require operating at variable speed.
This usually limited the size of the motor that could be managed by a frequency and they weren’t commonly used. The earliest VFDs utilized linear amplifiers to regulate all aspects of the VFD. Jumpers and dip switches were used provide ramp-up (acceleration) and ramp-down (deceleration) features by switching larger or smaller sized resistors into circuits with capacitors to make different slopes.
Hope you enjoyed this write-up, to find out more on Variable Speed Gear Motor see our site.