#MotorTalkMonday – direct on-line vs. variable frequency drive
When it comes to controlling motors, direct on-line starters and variable frequency drives are two of the most common approaches. Below, we have listed some of the key differences between the two.
Direct on-line (DOL):
• Motor receives full voltage instantly when started.
• Simple and inexpensive.
• Very high inrush current (6–8 times the rated current).
• Full torque available immediately.
With a Variable Frequency Drive (VFD):
• Voltage and frequency ramp up gradually.
• Soft starting — reduced inrush current.
• Torque can be controlled precisely.
• Improved energy efficiency, especially under partial loads.
The choice between a DOL starter and a VFD can largely depend on the specific requirements of your application. If you are interested in learning more or deciding if the switch to a VFD is the right move for you, click here to read more about the benefits of adding a drive or give us a call to discuss more! While we do not directly sell drives at the Tulsa district office, we can surely point you in the right direction!
