How Do Flameproof Variable Frequency Drives Change the Motor Speed?

  •  shreeelectric
  • 17 Nov

Electric motors with Flameproof variable frequency drives (VFDs) have become more popular in recent decades. The advantages are obvious: Flameproof VFD-equipped systems function more effectively, consume less energy, enable more accurate control, and lower maintenance costs.

VFD adoption has been slower when a motor is in an environment with flammable materials, gases, or liquids. Many customers have decided to operate their hazardous-duty or explosion-proof motors directly from a power supply in order to reduce environmental concerns.

That is beginning to change. Motors that employ starters must be cycled on and off manually to maximise energy consumption and reduce demand. This puts strain on motors and other mechanical devices while also increasing system output peaks.

The FVF Drive panel may do these and other duties with less dramatic variation by adjusting motor speed automatically, increasing motor life and boosting system efficiency. VFDs may eliminate the requirement for gear trains, belts, and gearboxes since they regulate a process at particular speeds.

As the industry learns more about the appropriate use of Variable Frequency Drive panel on motors in hazardous locations, many are reconsidering their use. However, not all VFDs are made equal in these instances. Before adding one to a new or current application, it is critical to undertake a system evaluation to understand the difficulties of your application. Then, choose a remedy that is both safe and in accordance with existing rules.

Crucial Aspects To Remember When FVF Drive Panel Change The Motor Speed

A variable frequency drive regulates the speed of an alternating current motor by altering the frequency supplied to the motor.

1.    Confirm That The Application’s Motor Is Approved For Use With A FVF Drive Panel In A Hazardous Environment

A hazardous-duty or explosion-proof motor can only be used with a VFD if it is clearly marked on the nameplate. Because VFDs employ a pulse width modulated (PWM) waveform to turn power on and off thousands of times per second, they may adjust motor speed. This fast cycling generates harmonics, which can generate additional heat inside the motor’s windings. You need a motor that can run at moderate speeds without overheating and survive larger voltage spikes, which are both critical in flammable environments. When studying the nameplate, check for two items to validate that your motor is allowed for usage with a VFD:

  • Identifying the motor as inverter duty-rated and confirming that the inverter rating is appropriate for the motor’s use.
  • Verify that the inverter duty rating is sufficient for the motor to be used in the anticipated hazardous area.

2.    Ascertain That The Motor Will Be Used Within The Speed Restrictions Specified On The Nameplate

The least speed at which the application may safely run should be used to design an inverter duty motor for a hazardous environment. For both constant torque (CT) and variable torque (VT) applications, inverter duty-rated motors often provide speed range information (found on the motor nameplate). CT applications, which include moving solids (e.g., a conveyor), have more restricted ranges on a given motor than VT applications, which include fans, pumps, and other applications that move air or water.

A motor’s operating range is described as a ratio that compares its maximum and minimum capacity. For example, a motor with a 10:1 ratio that operates nominally at 1,800 rpm can also run safely at 180 rpm. Because a VFD can impact ratio, the motors they control are tested for agency approval at various speeds and loads to ensure that the combinations’ effects do not invalidate any motor protections.

3.    Place The Vfd Where It Will Provide The Most Benefit At The Lowest Expense

A VFD can be installed within or outside the hazardous environment boundaries in which your motor is housed. Both have pros and cons. Choosing the best site requires effort, including a rigorous cost-benefit study of several choices.

For example, a drive positioned near a motor in a dangerous area will necessitate an explosion-proof casing and other safeguards. This additional cost is avoided when the VFD is positioned away from potentially hazardous settings. Any cost savings, however, will be outweighed by the additional cost of the wiring required to link the motor and VFD.

Motor load reactors or sine wave filters may be necessary to buffer VFD output depending on the horsepower and length of the motor cables — unless the VFD is co-located. Also, please note that the shaft grounding rings may be required to prevent early bearing failures. Therefore, they must be internally fitted to a hazardous-rated motor operated in a hazardous environment. Other filtering choices may be suggested by your drive or motor manufacturer to further reduce danger.

4.    Consider Environmental Dangers While Installing A VFD System

VFD installation criteria for hazardous-duty or explosion-proof motors are similar to those for general-purpose motors. The distinction lies in the repercussions that might occur when proper installation procedures are not followed or motor certification requirements are incorrect for the use of these inverter duty motors.

The motor must be grounded back to the drive, and the cabling, conduit, and filter must be properly sized and fitted.

Wrapping Up

While hazardous situations provide difficulties for the usage of VFD-controlled inverter duty motors, they may be overcome with proper design, product selection, and installation. The efficiency, productivity, and other advantages of these VFD systems will open up new avenues for usage in these contexts.